Image forming apparatus

Abstract

To ensure the necessary amount of intake and exhaust air, while preventing entry of foreign substances from a louver.SOLUTION: An image forming apparatus comprises: a vent hole 26 that is provided in an exterior cover; a cooling fan 22 that generates an air current passing through the vent hole 26; and a louver 21 that has an opening provided in the vent hole 26. The louver 21 has a foreign substance entry prevention louver 21a that is arranged at a position within a predetermined distance from the cooling fan 22, and an intake and exhaust louver 21b that is arranged at a position separated from the cooling fan 22 by the predetermined distance or more. An opening of the foreign substance entry prevention louver 21a is formed smaller than an opening of the intake and exhaust louver 21b.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present invention relates to a louver provided on an exterior cover of an image forming apparatus. [Background technology]

[0002] An image forming apparatus generates heat from the electric circuit boards, fixing unit, and other components installed inside the apparatus. To cool the inside of the apparatus, the image forming apparatus takes in and exhausts outside air. For this purpose, an exterior cover of the image forming apparatus is provided with a vent for intake and exhaust of outside air. A fan for intake and exhaust of outside air is placed inside the image forming apparatus near the vent. Louvers are sometimes installed in the vent to ensure safety (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-64896 Summary of the Invention [Problem to be solved by the invention]

[0004] As image forming devices become faster, the amount of heat generated inside tends to increase. At the same time, image forming devices are becoming smaller. To address this, cooling fans and vents are installed near heat sources such as electrical boards and fusers. Louvers installed in the vents have multiple openings to ensure the necessary amount of intake and exhaust. The area of ​​each opening is configured to be as large as possible. However, expanding the louver openings can allow foreign objects to enter the image forming device. These foreign objects may come into contact with the heat source or cooling fan inside the image forming device. Contact of foreign objects with the heat source or cooling fan can cause the image forming device to malfunction.

[0005] SUMMARY OF THE INVENTION In view of the above-mentioned problems, it is a primary object of the present invention to provide an image forming apparatus that can ensure the necessary amount of intake and exhaust air while preventing foreign matter from entering through the louvers. [Means for solving the problem]

[0006] The image forming apparatus of the present invention comprises an air vent provided in an outer cover, a fan that generates an airflow through the air vent, and louvers having openings provided in the air vent, wherein the louvers include a first louver that is positioned closer to the fan than a predetermined distance, and a second louver that is positioned farther from the fan than the predetermined distance, and the opening of the first louver is configured to be smaller than the opening of the second louver. [Effects of the Invention]

[0007] According to the present invention, it is possible to ensure the necessary amount of intake and exhaust air while preventing foreign matter from entering through the louvers. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is an external perspective view of an image forming apparatus. [Figure 2] FIG. 2 is a diagram illustrating the internal configuration of the image forming apparatus. [Figure 3] FIG. [Figure 4] Enlarged view of the area around the louvers. [Figure 5] Cross-sectional view from above near the louvers. [Figure 6] FIG. 10 is an explanatory diagram of the detailed shape of the foreign object intrusion prevention louver. [Figure 7] Cross-sectional view from above near the louvers. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

[0010] FIG. 1 is a perspective view of the appearance of an image forming apparatus according to this embodiment. The image forming apparatus 1 includes a document reading unit 41, an operation unit 46, a paper feed unit 42, and an output tray 13. The document reading unit 41 is a reader that reads an image from a document. The operation unit 46 is a user interface that has an input interface and an output interface. The input interface is, for example, various key buttons, a touch panel, etc. The output interface is a display, a speaker, etc. A user can make various settings for the image forming apparatus using the operation unit 46.

[0011] The paper feed unit 42 can store multiple sheets. In this embodiment, a configuration in which two paper feed units 42 are provided is illustrated, but the number of paper feed units 42 is not limited to this. Each paper feed unit 42 may store sheets of the same type and size, or may store sheets of different types and sizes. The image forming apparatus 1 prints an image on the sheets stored in the paper feed unit 42 and discharges them to the discharge tray 13.

[0012] 2 is a diagram showing the internal configuration of image forming apparatus 1. Image forming apparatus 1 includes sheet conveying section 43, image forming section 44, and fixing device 45. Sheet S is fed from paper feed unit 42, and while being conveyed to sheet conveying section 43, an image is transferred onto sheet S by image forming section 44, and the image is fixed by fixing device 45.

[0013] The image forming unit 44 includes four image forming units 3, an exposure device 2, four primary transfer units 5, and an intermediate transfer belt 7. Each of the four image forming units 3 includes a photosensitive drum 6. Each image forming unit 3 is a process cartridge having a charger, developer, and cleaner (not shown) around the photosensitive drum 6. Each of the four image forming units 3 forms a different color image on the photosensitive drum 6. In this embodiment, four color images are formed: yellow (Y), magenta (M), cyan (C), and black (K). The intermediate transfer belt 7 is disposed in contact with the top of the four photosensitive drums 6 and is driven counterclockwise in the drawing. The primary transfer units 5 are provided in one-to-one correspondence with the photosensitive drums 6. Each primary transfer unit 5 is disposed opposite its corresponding photosensitive drum 6 across the intermediate transfer belt 7.

[0014] The photosensitive drum 6 is a drum-shaped photosensitive body having a photosensitive layer on its surface. The photosensitive drum 6 rotates clockwise around the drum axis in the figure. The surface of the photosensitive drum 6 is uniformly charged by a charger. An electrostatic latent image is formed on the photosensitive drum 6 by exposing the uniformly charged surface to light by an exposure device 2. The electrostatic latent image is developed by a developer of a predetermined color by a developing device. As a result, a toner image of the predetermined color is formed on the photosensitive drum 6. The developing device is replenished with toner from a toner replenishing unit 12 so that the amount of toner contained therein remains constant.

[0015] As the photosensitive drums 6 rotate, the toner images are transported to a nip portion (the position of the primary transfer portion 5) formed between the photosensitive drums 6 and the intermediate transfer belt 7. The primary transfer portion 5 transfers the toner images on the photosensitive drums 6 to the intermediate transfer belt 7 by applying a predetermined bias voltage. The toner images of each color are transferred from each photosensitive drum 6 to the intermediate transfer belt 7 so as to be superimposed on each other.

[0016] In parallel with image formation by the image forming section 44, the sheet conveying section 43 feeds the sheets S one by one from the paper feeding unit 42. The sheet conveying section 43 has a pickup roller 10, a registration roller 9, a secondary transfer roller 8, a discharge roller 18, and a reverse conveying roller 17.

[0017] A pickup roller 10 is provided for each paper feed unit 42. The pickup roller 10 feeds one sheet S stored in the paper feed unit 42 and conveys it to the registration rollers 9. The registration rollers 9 correct any skew of the sheet S, and then convey the sheet S to a nip portion formed by the secondary transfer roller 8 and the intermediate transfer belt 7. The registration rollers 9 convey the sheet S to the nip portion in accordance with the timing at which the toner images of each color carried by the intermediate transfer belt 7 are conveyed to the nip portion.

[0018] A predetermined bias voltage is applied to the secondary transfer roller 8, which transfers the toner images of each color carried on the intermediate transfer belt 7 all at once onto the sheet S. The secondary transfer roller 8 transports the sheet S onto which the toner images have been transferred to the fuser 45. The fuser 45 has a fuser roller 11a incorporating a heat source and a pressure roller 11b. The fuser 45 fixes the toner images onto the sheet S by sandwiching and transporting the sheet S between the fuser roller 11a and the pressure roller 11b. The fuser 45 heats the sandwiched sheet S with the heat source of the fuser roller 11a and applies pressure to the sheet S with the pressure roller 11b. The toner images melt and mix due to the heat and pressure applied, and are fixed to the sheet S.

[0019] The sheet S with the fixed toner image is discharged to the discharge tray 13 by the discharge rollers 18. In the case of double-sided printing, the sheet S with the image printed on the first side is partially discharged outside the machine by the discharge rollers 18, and then the discharge rollers 18 rotate in the reverse direction to convey the sheet to the reversing conveying rollers 17. This reverses the printed side of the sheet S from the first side to the opposite side, the second side. The reversing conveying rollers 17 convey the sheet S to the registration rollers 9. The toner image is transferred and fixed to the second side of the sheet S conveyed to the registration rollers 9 in the same way as when printing on the first side, and the sheet S is then discharged to the discharge tray 13.

[0020] In the image forming apparatus 1 configured as described above, an exterior cover is provided with an outside air vent to exhaust heat from inside the apparatus. Louvers are provided in the vent to ensure safety. The shape of the louvers in this embodiment will be described with reference to Figs. 3 to 5. Fig. 3 is a perspective view of the louvers of the image forming apparatus 1. The louvers 21 are provided in the exterior cover 20 of the image forming apparatus 1. Although hidden by the louvers 21, a vent is provided in the exterior cover 20 at the position where the louvers 21 are provided. Fig. 4 is an enlarged view of the vicinity of the louvers 21 in Fig. 3. The louvers 21 include foreign object intrusion prevention louvers 21a and intake / exhaust louvers 21b. Fig. 5 is a cross-sectional view from above of the vicinity of the louvers 21.

[0021] A duct 23, a cooling fan 22, and an electric board 24 are arranged near the louver 21 inside the image forming apparatus 1. The electric board 24 is, for example, a control board that controls the operation of each component in the image forming apparatus 1 or a power board that supplies power voltage to each component. The electric board 24 is a heat source. Outside air (e.g., air) is drawn into and exhausted from the exterior cover 20 (inside the machine body) through the vent 26 and the louver 21. The cooling fan 22 has multiple fins and rotates to direct the air drawn in through the vent 26 and the louver 21 toward the electric board 24, thereby cooling the electric board 24. The air that has cooled the electric board 24, along with the heat generated in the electric board 24, is discharged from the louver 21 to the outside of the exterior cover 20 through the duct 23. In this way, the cooling fan 22 generates an airflow that passes through the vent 26.

[0022] The cooling fan 22 may be configured to exhaust heat generated in the electric board 24 through the duct 23, the vent 26, and the louver 21 to the exterior cover 20 (outside the fuselage). In this case, the outside air flowing into the interior of the exterior cover 20 from the louver 21 directly cools the electric board 24. The cooling fan 22 may also be configured with two fans: one fan that blows (takes in) outside air onto the electric board 24, and the other fan that exhausts heat generated in the electric board 24.

[0023] As image forming apparatuses 1 become smaller, the vents 26 and louvers 21 are often positioned near the electrical board 24 and cooling fan 22. In this case, foreign objects such as dust may enter the image forming apparatus 1 through the openings of the louvers 21 and come into contact with the nearby cooling fan 22 or electrical board 24. If a metallic foreign object such as a paper clip enters the interior of the apparatus, contact with the cooling fan 22 may damage the fins of the cooling fan 22, resulting in a decrease in cooling function, or may cause the fins to rattle, resulting in abnormal noise. Similarly, if a metallic foreign object comes into contact with the electrical board 24, it may cause a short circuit or damage. If the electrical board 24 shorts out or is damaged, the image forming apparatus 1 may stop operating. The impact of contact with a metallic foreign object is particularly significant when the electrical board 24 is a power board.

[0024] It is possible to prevent foreign matter from entering by filling the openings of the louver 21 provided near the electrical board 24 and the cooling fan 22. However, in this case, there is a possibility that the amount of intake and exhaust required for cooling may not be ensured. Increasing the rotation speed of the cooling fan 22 to ensure the amount of intake and exhaust would require a more expensive fan. Furthermore, increasing the rotation speed of the cooling fan 22 increases the vibration of the cooling fan 22 itself, and the increased amount of intake and exhaust increases wind noise, resulting in increased noise. For this reason, filling the openings of the louver 21 is not an effective measure to prevent foreign matter from entering.

[0025] It is possible to prevent the intrusion of foreign matter by reducing the area of ​​the opening of louver 21 to a level that prevents foreign matter from entering. However, in this case, the flow resistance increases, making it difficult for air to flow, and there is a possibility that the amount of intake and exhaust air required for cooling cannot be secured. As a result, just as in the case where the opening itself is filled in, it becomes necessary to increase the speed of cooling fan 22, resulting in increased noise. In this way, reducing the area of ​​the opening of louver 21 to a level that prevents foreign matter from entering is not an effective measure for preventing the intrusion of foreign matter.

[0026] In this embodiment, as described above, two types of louvers 21 are provided: foreign object intrusion prevention louvers 21a and intake / exhaust louvers 21b. Foreign object intrusion prevention louvers 21a are louvers that are arranged near the electric board 24 and the cooling fan 22, where there is a high risk of foreign objects intruding. Intake / exhaust louvers 21b are louvers that are arranged at a distance from the electric board 24 and the cooling fan 22, where there is a low risk of foreign objects reaching these components even if they intrude. The opening of foreign object intrusion prevention louver 21a is smaller than the opening of intake / exhaust louvers 21b. The intake / exhaust louvers 21b ensure the amount of intake and exhaust air required for cooling. The foreign object intrusion prevention louvers 21a are arranged so that their distance to the electric board 24, which is a heat source, is shorter than that of intake / exhaust louvers 21b.

[0027] The intake and exhaust louvers 21b are provided on a surface that is not parallel to the airflow direction X of the cooling fan 22. The intake and exhaust louvers 21b are louvers that compensate for the reduced intake and exhaust volume caused by the provision of the foreign object intrusion prevention louvers 21a. For this reason, the intake and exhaust louvers 21b, which have good airflow efficiency, are arranged as perpendicular as possible to the airflow direction X of the cooling fan 22, thereby ensuring the necessary intake and exhaust volume.

[0028] Even when the image forming apparatus 1 is installed against the wall of a building or the like, the amount of intake and exhaust air required for cooling must be ensured. For this reason, the intake and exhaust louvers 21b are arranged at an angle to the airflow direction X of the cooling fan 22. This prevents the opening of the louvers 21 from being blocked even when the exterior cover 20 comes into contact with the wall of a building or the like.

[0029] The airflow effect can be maximized by arranging the intake and exhaust louvers 21b perpendicular to the airflow direction X of the cooling fan 22. The intake and exhaust louvers 21b need to be located close to the electric board 24 and the cooling fan 22 from the surface of the exterior cover 20 so that the opening is not blocked by the wall of the building. If both of these requirements are met, the risk of foreign matter entering through the opening of the intake and exhaust louvers 21b increases, and it becomes impossible to ensure both the required intake and exhaust volume and the function of preventing the intrusion of foreign matter. For this reason, the intake and exhaust louvers 21b are arranged at an angle to the airflow direction X of the cooling fan 22 so that the required intake and exhaust volume can be ensured while maintaining a predetermined distance from the electric board 24 and the cooling fan 22 that reduces the risk of foreign matter entering.

[0030] In this embodiment, the distance at risk of foreign object intrusion is set to within the required distance L of 100 mm from the live parts of the electric board 24 that may short out due to contact with the foreign object. The foreign object intrusion prevention louvers 21a are provided at a position closer than the required distance L from the live parts of the electric board 24. The intake and exhaust louvers 21b are provided at a position farther than the required distance L from the live parts of the electric board 24. Note that in this embodiment, both the cooling fan 22 and the electric board 24 are located near the louvers 21, but the same effect can be achieved with a configuration that includes only the cooling fan 22 or only the electric board 24.

[0031] 6 is an explanatory diagram of the detailed shape of foreign object intrusion prevention louver 21a. The size of each opening of foreign object intrusion prevention louver 21a is 5 mm or less in the diagonal length of the opening, or 1 mm or less in either the vertical or horizontal length of the opening. This size is set to prevent the intrusion of small metallic foreign objects such as clips and necklace chains.

[0032] (Variation) Louvers 21 are provided near heat sources inside image forming apparatus 1 in addition to electric board 24. Here, the heat source will be described using fixing unit 45 as an example. FIG. 7 is a cross-sectional view from above of the vicinity of louvers 21 provided near fixing unit 45. Cooling fan 22 is disposed on the side of fixing unit 45. Cooling fan 22 guides heat generated by fixing unit 45 and water vapor generated when sheet S is heated to ventilation opening 26 via duct 23, and discharges the heat to the outside of the machine via louvers 21 provided in exterior cover 20.

[0033] Control board 25 that controls fixing unit 45 is disposed in a direction different from the airflow direction X of cooling fan 22. Because control board 25 is disposed in this manner, the amount of intake and exhaust by cooling fan 22 is ensured.

[0034] Foreign object intrusion prevention louver 21a is disposed close to cooling fan 22, and intake / exhaust louver 21b is disposed farther away. Intake / exhaust louver 21b is disposed obliquely with respect to the airflow direction X of cooling fan 22. Intake / exhaust louver 21b is disposed at a position at least a predetermined distance away from fuser 45. In this case, unlike electric board 24, no short circuit will occur even if a metallic foreign object comes into contact with fuser 45, so the predetermined distance is shorter than necessary distance L.

[0035] As described above, the louvers 21 include the foreign object intrusion prevention louvers 21a and the intake / exhaust louvers 21b, with the foreign object intrusion prevention louvers 21a being provided near the heat source and the cooling fan 22, and the intake / exhaust louvers 21b being provided away from the heat source and the cooling fan 22. This makes it possible to ensure the necessary amount of intake and exhaust of outside air while preventing foreign objects that have infiltrated through the louvers 21 from affecting the heat source and the cooling fan 22. This maintains the cooling effect of the cooling fan 22.

Claims

1. a ventilation hole provided in the exterior cover; a fan that generates an airflow through the vent; a louver having an opening provided in the ventilation port, the louvers include a first louver arranged at a position closer to the fan than a predetermined distance, and a second louver arranged at a position farther from the fan than the predetermined distance, The opening of the first louver is configured to be smaller than the opening of the second louver. Image forming device.

2. The fan cools a heat source, The distance from the first louver to the heat source is shorter than the distance from the second louver to the heat source.

2. The image forming apparatus according to claim 1.

3. The heat source is an electric substrate.

3. The image forming apparatus according to claim 2.

4. The first louver is disposed at a position closer to the electric board than the predetermined distance.

4. The image forming apparatus according to claim 3.

5. The first louver is disposed within 100 mm of the electric board.

4. The image forming apparatus according to claim 3.

6. The heat source is a fixing device that fixes an image on a sheet.

3. The image forming apparatus according to claim 2.

7. a control board for controlling the fixing unit is disposed in a direction different from the airflow direction of the fan, 7. The image forming apparatus according to claim 6.

8. The opening of the first louver has a diagonal length of 5 mm or less, or either the vertical or horizontal length of the opening is 1 mm or less.

2. The image forming apparatus according to claim 1.

9. The second louver is disposed obliquely with respect to the direction of air blown by the fan.

2. The image forming apparatus according to claim 1.

Images