Image forming apparatus

Abstract

The invention provides an image forming apparatus. The image forming apparatus includes: an image forming section; a discharge port configured to discharge the recording medium on which the image is formed by the image forming portion; a wall portion in which the discharge port is provided; a bottom portion on which the recording medium is to be stacked; the upper part is opposite to the bottom part; a side portion provided along a discharge direction of the recording medium; a discharge space defined by at least the wall portion, the bottom portion, the upper portion, and the side portion, and accommodating the recording medium discharged from the discharge port; a plurality of through holes provided at least in any of the wall portion, the bottom portion, the upper portion, and the side portion; and a sound absorbing material covering the plurality of through holes on the side opposite to the discharge space.

Description

Technical Field

[0001] The present disclosure relates to an image forming apparatus including a sound absorbing material. Background Art

[0002] In recent years, image forming devices such as copiers have become widely popular and installed in various usage environments. Therefore, quietness during operation, which has a relatively low priority in the prior art, has also become increasingly important. At the same time, in office equipment, as the printing speed increases, the sounds generated inside the device (such as driving sounds, paper sounds, and fan sounds) also tend to increase, so noise reduction is now an important issue. In particular, the discharge space in the body (discharge recording medium accommodating space) for accommodating recording media formed with images is always an open space, so that the user can immediately remove the recording medium. The sound generated inside the device is output from the discharge port, thereby leaking to the outside of the image forming device.

[0003] In order to solve such a problem, Japanese Patent Application Laid-Open No. 2017-156766 proposes a technology in which a sound absorbing unit using a Helmholtz resonator is provided on the upper surface of an in-body discharge space for accommodating a recording medium having an image formed by an image forming unit.

[0004] However, in recent years, it is desired to further reduce the size of the image forming apparatus, and the space for installing the sound absorbing unit using the Helmholtz resonator in the image forming apparatus is limited. The shape of the Helmholtz resonator is like a container with a narrow port, so it is necessary to ensure a space for setting the cavity part in the Helmholtz resonator. This space causes the size of the main body of the image forming apparatus to increase. In addition, the size of the sound absorbing hole used as the sound absorbing part is smaller than the size of the internal cavity part, so the number of sound absorbing holes that can be arranged is limited by the size of the cavity part. Summary of the invention

[0005] According to one aspect of the present disclosure, an image forming device includes: an image forming portion, which is configured to form an image on a recording medium; a discharge port, which is configured to discharge the recording medium on which the image is formed by the image forming portion; a wall portion, in which the discharge port is arranged; a bottom portion, on which the recording medium discharged from the discharge port is to be stacked; an upper portion, which is arranged to be opposite to the bottom portion; a side portion, which is arranged along a discharge direction of the recording medium discharged from the discharge port; a discharge space, which is defined by at least the wall portion, the bottom portion, the upper portion and the side portion, wherein the discharge space accommodates the recording medium discharged from the discharge port; a plurality of through holes, which are arranged in at least any of the wall portion, the bottom portion, the upper portion and the side portion; and a sound absorbing material, which is arranged to cover the plurality of through holes on a side opposite to the discharge space relative to a portion of at least the wall portion, the bottom portion, the upper portion and the side portion in which the plurality of through holes are arranged.

[0006] Further features of the present disclosure will become apparent from the following description of exemplary embodiments with reference to the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 is a perspective view of the image forming apparatus according to the first embodiment.

[0008] Figure 2 is a sectional view of the image forming apparatus according to the first embodiment.

[0009] Figure 3 1 is a perspective view of the exhaust space in the machine body in the first embodiment.

[0010] Figure 4 is a sectional view of the image forming apparatus given when the discharge tray in the first embodiment is viewed from above.

[0011] Figure 5 1 is a schematic diagram for illustrating the back side of the in-body discharge cover in the first embodiment.

[0012] Fig. 6A , Figure 6B and Figure 6C Schematic diagram of the perforated surface of the in-body discharge cover in the first embodiment.

[0013] Figure 7 2 is a cross-sectional view of the perforated surface of the in-body discharge cover and the sound absorbing sheet in the first embodiment.

[0014] Figure 8 is a perspective view for illustrating an in-body exhaust space of an image forming apparatus according to another embodiment.

[0015] Fig.9A , Fig. 9B and Fig. 9C It is a figure for showing the in-body exhaust cover and the sound absorbing sheet in another embodiment.

[0016] Fig.10 is a sectional view of an image forming apparatus according to a second embodiment.

[0017] Fig.11 is a sectional view of an image forming apparatus according to a third embodiment. DETAILED DESCRIPTION

[0018] Modes for carrying out the present disclosure will now be described with reference to the drawings.

[0019] [First embodiment]

[0020] Now, an image forming device 1 according to a first embodiment is described with reference to the accompanying drawings. The sound absorbing unit of the first embodiment is used in, for example, the image forming device 1 described later, but is not always limited to this mode. Hereinafter, embodiments of the present disclosure will be illustratively described in detail with reference to the accompanying drawings. However, the sizes, materials, and shapes of the components described in the following embodiments and their relative positions may be appropriately changed according to the configuration and various conditions of the device to which the present disclosure is applied. Therefore, unless specifically described, it is not intended to limit the scope of the present disclosure to only these exemplary embodiments.

[0021] (Image Forming Apparatus)

[0022] Figure 1 is a perspective view of the image forming apparatus 1 according to the first embodiment. Figure 2 : is a cross-sectional view of the image forming apparatus 1 according to the first embodiment. The image forming apparatus 1 according to the first embodiment is an in-body discharge type image forming apparatus. In the image forming apparatus 1 according to the first embodiment, the side on which the user stands when operating the operation unit 10 is referred to as the "front", and the side opposite thereto is referred to as the "back". In addition, the left side viewed from the front is referred to as the "left", and the right side viewed from the front is referred to as the "right". Therefore, Figure 2 A cross section of the image forming apparatus 1 is shown when the image forming apparatus 1 is viewed from the front.

[0023] Reference Figure 1 and Figure 2 The image forming apparatus 1 includes a document reading section (reader) 41, a sheet feeding section 42, a sheet conveying section 43, an image forming section 44, a fixing section 45, and an operation section 10. The image forming section 44 includes four photosensitive drums 6Y, 6M, 6C, and 6K for forming a toner image. Figure 2, each of the photosensitive drums 6Y, 6M, 6C, and 6K rotates clockwise. Around the photosensitive drums 6Y, 6M, 6C, and 6K, charging devices 8Y, 8M, 8C, and 8K, developing devices 4Y, 4M, 4C, and 4K, and cleaners 7Y, 7M, 7C, and 7K are arranged, respectively. The photosensitive drums 6Y, 6M, 6C, and 6K, the charging devices 8Y, 8M, 8C, and 8K, the developing devices 4Y, 4M, 4C, and 4K, and the cleaners 7Y, 7M, 7C, and 7K form image forming units 3Y, 3M, 3C, and 3K as process cartridges, respectively. The image forming units 3Y, 3M, 3C, and 3K form an image forming portion 44 serving as an image forming portion.

[0024] Above the image forming section 44, an intermediate transfer belt 14 serving as an intermediate transfer unit is arranged so as to contact the photosensitive drums 6Y, 6M, 6C, and 6K. The intermediate transfer belt 14 is stretched by a driving roller 62 and two driven rollers 63 and 65. Figure 2 , the intermediate transfer belt 14 rotates counterclockwise. The primary transfer rollers 5Y, 5M, 5C, and 5K are arranged to face the photosensitive drums 6Y, 6M, 6C, and 6K, respectively, across the intermediate transfer belt 14. The primary transfer rollers 5Y, 5M, 5C, and 5K form primary transfer sections between the intermediate transfer belt 14 and the photosensitive drums 6Y, 6M, 6C, and 6K, respectively. Above the intermediate transfer belt 14, toner replenishing sections 32Y, 32M, 32C, and 32K for supplying toners of respective colors to the developing devices 4Y, 4M, 4C, and 4K are arranged.

[0025] The image forming unit 3Y forms a yellow toner image, the image forming unit 3M forms a magenta toner image, the image forming unit 3C forms a cyan toner image, and the image forming unit 3K forms a black toner image. The structures of the image forming units 3Y, 3M, 3C, and 3K are basically the same, so the image forming unit 3Y is described below. The surface of the photosensitive drum 6Y is uniformly charged by the charging device 8Y. The exposure unit 15 irradiates the uniformly charged surface of the photosensitive drum 6Y with light modulated based on the yellow image signal, thereby forming a latent image on the surface of the photosensitive drum 6Y. The developing device 4Y develops the latent image formed on the surface of the photosensitive drum 6Y with the yellow toner supplied from the toner replenishing section 32Y, thereby forming a yellow toner image on the photosensitive drum 6Y.

[0026] As the photosensitive drum 6Y rotates, the yellow toner image reaches the primary transfer portion where the photosensitive drum 6Y and the intermediate transfer belt 14 abut against each other. A primary transfer bias is applied from a circuit board (not shown) to the primary transfer roller 5Y disposed opposite to the photosensitive drum 6Y, so that the primary transfer roller 5Y transfers the yellow toner image formed on the surface of the photosensitive drum 6Y to the intermediate transfer belt 14. Similarly, the magenta, cyan, and black toner images formed on the surfaces of the photosensitive drums 6M, 6C, and 6K are sequentially transferred to the intermediate transfer belt 14 by the primary transfer rollers 5M, 5C, and 5K.

[0027] A sheet S, which serves as a recording medium accommodated in a sheet feeding portion 42 serving as a feeding unit, is fed by a pickup roller 67, and is separated one by one by a separation feeding portion 16 to be fed to a registration roller 9. The registration roller 9 starts conveying the sheet S in synchronization with the timing of the transfer of the toner image onto the intermediate transfer belt 14, and conveys the sheet S to a secondary transfer portion T2 formed between a secondary transfer roller 28 and the intermediate transfer belt 14. The secondary transfer roller 28 transfers the toner image formed on the intermediate transfer belt 14 onto the sheet S at the secondary transfer portion T2. ​​The sheet S to which the toner image is transferred is conveyed to a fixing portion 45. The fixing portion 45 applies heat and pressure to the sheet S, thereby causing the toner to melt and mix to be fixed on the sheet S, so that a color image is formed on the sheet S. The sheet S to which the image is formed is discharged to a discharge tray 19 by a discharge roller 18 provided downstream of the fixing portion 45. The discharge roller 18 includes a discharge port 181 for discharging the sheet S.

[0028] The image forming device 1 can operate in a single-sided printing mode in which an image is formed on one surface of a sheet S and in a double-sided printing mode in which an image is formed on both surfaces of the sheet S. In the single-sided printing mode, the sheet S on which an image is formed on one surface of the sheet S as described above is discharged to the discharge tray 19 by the discharge roller 18. In the double-sided printing mode, the sheet S on which an image is formed on one surface (first surface) is conveyed to the reverse conveying path 21 by the reverse rotation of the discharge roller 18. The sheet S is re-conveyed to the secondary transfer section T2 by the reverse conveying roller 17 arranged in the reverse conveying path 21. In the secondary transfer section T2, the toner image is transferred to the back side (second surface) of the sheet S. The sheet S is conveyed to the fixing section 45, and the toner image is fixed to the back side of the sheet S, so that a color image is formed. The sheet S on which images are formed on both surfaces is discharged to the discharge tray 19 by the discharge roller 18.

[0029] (Exhaust space in the machine body)

[0030] Next, refer to Figure 3 The in-body discharge space SP serving as the discharge space of the image forming apparatus 1 according to the first embodiment is described. Figure 31 is a perspective view of the in-machine discharge space SP in the first embodiment. In the image forming apparatus 1, the document reading section 41 is arranged above the discharge tray 19 on which the sheets S discharged from the discharge port 181 are to be stacked. An in-machine discharge space SP portion to accommodate the sheets S discharged from the discharge port 181 is formed between the discharge tray 19 and the document reading section 41. In the image forming apparatus 1, the image forming section 44 is arranged below the in-machine discharge space SP. In the image forming apparatus 1, the in-machine discharge cover 11 is arranged on the back side of the in-machine discharge space SP. In the image forming apparatus 1, the discharge port surface (wall portion) 20 formed with the discharge port 181 is arranged on the right side of the in-machine discharge space SP. The in-machine discharge space SP is defined by at least four surfaces, including: the discharge tray 19 serving as a bottom surface (bottom), the discharge port surface 20, the lower surface 41a of the document reading section 41 serving as an upper surface (upper portion), and the in-machine discharge cover 11 serving as a side surface (side portion).

[0031] Figure 4 1 is a cross-sectional view of the image forming apparatus 1 when the discharge tray 19 in the first embodiment is viewed from above. The sheets S discharged from the discharge port 181 are stacked on the discharge tray 19 in the in-body discharge space SP. The in-body discharge cover 11 serving as a perforated plate is provided on the back side of the in-body discharge space SP. Figure 4 The arrow indicates the discharge direction A of the sheet S discharged from the discharge port 181. The in-machine discharge cover 11 forms a side surface (side portion) disposed along the discharge direction A of the in-machine discharge space SP.

[0032] The sound-absorbing sheet (sound-absorbing material) 12 is arranged to abut on the back side of the in-body discharge cover 11. The in-body discharge cover 11 and the sound-absorbing sheet 12 form a sound-absorbing device 13 for absorbing the sound output from the discharge port 181. The sound-absorbing sheet 12 is formed by a sheet-like member having sound-absorbing properties (such as ethylene-propylene rubber (EPDM) foam or polyurethane foam, glass wool material made of glass fiber, or mineral rock wool material). However, for example, a plate-like, block-like or cotton-like sound-absorbing material can be used instead of the sound-absorbing sheet 12. A plurality of sound-absorbing holes 111 are formed in the in-body discharge cover 11. The plurality of sound-absorbing holes 111 are a plurality of through holes that pass through the in-body discharge cover 11. The plurality of sound-absorbing holes 111 are all covered with the sound-absorbing sheet 12 on the back side of the in-body discharge cover 11. In this case, the phrase "the plurality of sound absorbing holes 111 are covered with the sound absorbing sheet 12 on the back side of the in-body discharge cover 11" means that the in-body discharge cover 11 and the sound absorbing sheet 12 are adjacent to each other, and when viewed from a direction orthogonal to the in-body discharge cover 11, the plurality of sound absorbing holes 111 and the sound absorbing sheet 12 overlap each other. A portion of the main body operation sound output from the discharge port 181 enters the sound absorbing sheet 12 through the sound absorbing holes 111, and when the sound is greatly diffused in the sound absorbing sheet 12, part of the sound energy is converted into heat energy. Therefore, the sound leaking to the outside of the device body is reduced.

[0033] The plurality of sound absorbing holes 111 and the sound absorbing sheet 12 covering the holes may be provided in the entire area of ​​the in-body discharge cover 11, or may be provided in a portion of the in-body discharge cover 11. The plurality of sound absorbing holes 111 and the sound absorbing sheet 12 covering the holes may be provided in a plurality of portions of the in-body discharge cover 11. In addition, the plurality of sound absorbing holes 111 and the sound absorbing sheet 12 covering the holes may be provided in a portion of the in-body discharge cover 11 on the side opposite to the discharge port 181 with respect to the center position of the discharge direction A of the plate S. When the plurality of sound absorbing holes 111 and the sound absorbing sheet 12 covering the holes are provided near the opening portion of the in-body discharge space SP, the sound propagating from the in-body discharge space SP to the user may be reduced.

[0034] In the first embodiment, the in-body discharge cover 11 and the sound absorbing sheet 12 are in contact with each other. When the in-body discharge cover 11 and the sound absorbing sheet 12 are in contact with each other, the vibration of the in-body discharge cover 11 is reduced by the sound absorbing sheet 12. Therefore, by utilizing the contact between the in-body discharge cover 11 and the sound absorbing sheet 12, more effective noise reduction of the image forming device 1 can be achieved. In the first embodiment, the sound absorbing sheet (sound absorbing material) 12 is set to abut against the in-body discharge cover 11, but the sound absorbing sheet 12 can be arranged to be separated from the in-body discharge cover 11.

[0035] Generally speaking, it is preferable that the sound absorbing sheet 12 is thicker because the thicker sound absorbing sheet 12 can adapt to the sound of a wider frequency band, so it is likely to obtain a noise reduction effect. In the first embodiment, in order to obtain a high effect at a low cost, a sound absorbing sheet 12 with a thickness of "5mm" formed of EPDM-type foam is used. When an EPDM-type or polyurethane-type sound absorbing sheet 12 is used, it is difficult to obtain a noise reduction effect when the sound absorbing sheet 12 is compressed. In view of the above, the sound absorbing sheet 12 is installed between the in-body discharge cover 11 and the wall surface of the device body to prevent the sound absorbing sheet 12 from being compressed.

[0036] The exhaust space SP in the machine body is not limited to Figure 3 and Figure 4 shown. Figure 8 1 is a perspective view for illustrating an in-body discharge space SP1 of an image forming apparatus 101 according to another embodiment. In the image forming apparatus 101, the in-body discharge space SP1 is formed so that a user standing in front of the operation portion 10 and the discharge port 181 face each other. The in-body discharge space SP1 of the image forming apparatus 101 may be defined by five surfaces, including: a discharge tray 19 as a bottom surface, a discharge port surface 20, a lower surface 41a of the document reading portion 41 serving as an upper surface (which is disposed opposite to the discharge tray), a left side surface 22, and a right side surface 23. In this case, the sound absorbing device 13 formed by the in-body discharge cover 11 and the sound absorbing sheet 12 may be provided only on the left side surface (side surface) 22, may be provided only on the right side surface (the other side surface) 23, or may be provided on both the left side surface 22 and the right side surface 23.

[0037] (Discharge cover inside the machine body)

[0038] Next, refer to Figure 5 The in-body discharge cover 11 in the first embodiment will be described. Figure 5 : is a schematic diagram for illustrating the back side of the in-body discharge cover 11 in the first embodiment. The in-body discharge cover 11 in the first embodiment includes a perforated surface (perforated wall surface portion) 112, a sound absorbing sheet bonding surface 113, and a main body mounting portion 114. One or two or more sound absorbing holes 111 are formed in the perforated surface 112. A hole 114a that allows a screw to pass through is formed in each of the main body mounting portions 114. The screw is passed through the hole 114a to be screwed into a screw hole formed in the main body of the image forming device 1. Therefore, the in-body discharge cover 11 is fixed to the main body of the image forming device 1. At this time, in order to prevent the sound absorbing sheet 12 from being compressed, a gap for arranging the sound absorbing sheet 12 is formed between the in-body discharge cover 11 and the main body of the image forming device 1.

[0039] An adhesive member (such as an adhesive, glue, or double-sided tape) for mounting the sound absorbing sheet 12 on the in-body discharge cover 11 is applied to the sound absorbing sheet adhesive surface 113. The sound absorbing sheet adhesive surface 113 may be installed with a fastening member (such as a screw or a bolt) to mount the sound absorbing sheet 12 to the in-body discharge cover 11. In the first embodiment, the sound absorbing sheet 12 is bonded to the in-body discharge cover 11 using a double-sided tape having a pressure-sensitive adhesive property. However, when the double-sided tape closes even part of the sound absorbing hole 111, the noise reduction effect obtained by the sound absorbing hole 111 is reduced compared to the case where the sound absorbing hole 111 is not closed. In view of the above, the double-sided tape bonds the sound absorbing sheet 12 to the sound absorbing sheet adhesive surface 113 (the area indicated by the hatching) where the sound absorbing hole 111 is not formed, in other words, the area outside the area where the sound absorbing hole 111 is formed.

[0040] The discharge cover 11 in the machine body is not limited to Figure 5 For example, the in-body discharge cover 11 may be configured to hold the sound absorbing sheet 12 without using an adhesive member. Fig.9A , Fig. 9B and Fig. 9C It is a diagram for illustrating an in-body discharge cover 201 and a sound absorbing sheet 202 in another embodiment. Fig.9A 2 is a perspective view of an in-body discharge cover 201 equipped with a sound absorbing sheet 202. In the in-body discharge cover 201, a hook portion (engagement portion) 203, a stopper portion 204, a boss 205, a center protrusion 206, and a lower protrusion 207 are provided. Fig. 9B 2 is a front view of the sound absorbing sheet 202. Slit portions (joined portions) 208 penetrating the sound absorbing sheet 202 are formed at the upper left and upper right portions of the sound absorbing sheet 202. Fig. 9C is along Fig.9A A cross-sectional view taken along the line IXC-IXC. Fig. 9C As shown, the hook portion 203 of the in-body discharge cover 201 is inserted into the slit portion 208 of the sound absorbing sheet 202, so that the sound absorbing sheet 202 is hung on the hook portion 203. In this way, the sound absorbing sheet 202 is supported by the in-body discharge cover 201 in the form of being hung by the hook portion 203. When the in-body discharge cover 201 is mounted on the main body of the image forming apparatus 1, at least one of the hook portion 203, the anti-detachment portion 204, the boss 205, the central protrusion 206, and the lower protrusion 207 of the in-body discharge cover 201 abuts against the main body of the image forming apparatus 1. In this way, a gap for arranging the sound absorbing sheet 202 is formed between the in-body discharge cover 201 and the main body of the image forming apparatus 1, so that the sound absorbing sheet 202 is prevented from being compressed.

[0041] The hook-shaped portion 203 provided in the in-body discharge cover 201 is not limited to Fig. 9CThe slit portion 208 provided in the sound absorbing sheet 202 is not limited to the shape shown in the figure, but only requires a joint portion such as a protrusion. Fig. 9B The shape shown is only required to be an engaged portion (such as a hole, a recessed portion or a through hole) engaged with an engaging portion provided in the in-body discharge cover 201.

[0042] As described above, in order to reduce the sound output from the in-body exhaust space SP to the outside of the image forming device 1, it has been considered to provide a silencing mechanism in the in-body exhaust space SP. For example, a Helmholtz resonator used as a silencing mechanism is included in the in-body exhaust space SP, so that the sound output from the in-body exhaust space SP to the outside of the image forming device 1 is reduced. However, recently, it is desired to further reduce the size of the image forming device 1, and the space in which the Helmholtz resonator can be installed in the in-body exhaust space SP is limited. Specifically, if the frequency of the operating sound in the device is "500Hz", since the speed of sound in the air is "about 331,000mm / s", it is necessary to install a Helmholtz resonator with a depth of about "50mm". However, the latest image forming device 1 does not have such a large space to install a Helmholtz resonator of this size.

[0043] In view of the above, in the first embodiment, the following configuration is proposed: the sound is reduced by holding the sound absorbing sheet 12 having a thickness of "5 mm" on the internal discharge cover 11 having a thickness of about "3 mm". In this way, the sound output from the internal discharge space SP to the outside of the image forming apparatus 1 can be reduced while suppressing the increase in the size of the main body. Figure 4 As shown, in the first embodiment, the depth (distance) L of the gap between the in-body discharge cover 11 and the main body of the image forming apparatus 1 in which the sound absorbing sheet 12 is arranged is set to about 6 mm in consideration of the thickness of the double-sided tape. Therefore, according to the first embodiment, the space for arranging the sound absorbing device 13 can be greatly reduced compared to the case where the Helmholtz resonator is installed.

[0044] (Piercing wall surface)

[0045] Next, refer to Fig. 6A , Figure 6B and Figure 6C The configuration in the perforated surface 112 of the in-body discharge cover 11 is described. Fig. 6A , Figure 6B and Figure 6C 1 is a schematic diagram of the perforated surface 112 of the in-body discharge cover 11 in the first embodiment. Fig. 6AAs shown, each of the sound absorbing holes 111 formed in the perforated surface 112 is an elongated circular hole whose radius "d" is "1.5 mm or more and 6 mm or less", and whose width "w" is "3 mm or more and 30 mm or less". It is not required that all the sound absorbing holes 111 have the same hole diameter. When the radius "d" of the sound absorbing hole 111 is less than 1.5 mm, the strength of the mold for molding the in-body discharge cover 11 with resin becomes weak. Therefore, the radius "d" is set to be 1.5 mm or more. At the same time, when the radius "d" is greater than 6 mm, that is, the diameter is greater than 12 mm, since the width of an adult's finger is generally greater than 12 mm, the finger of the user who takes out the sheet S stacked in the in-body discharge space SP may enter the sound absorbing hole 111 by mistake. Therefore, the radius "d" is set to be 6 mm or less. In the first embodiment, all the sound absorbing holes 111 are set to: the radius "d" is "3 mm" and the width "w" is "20 mm".

[0046] The shape of the sound absorbing hole 111 is not limited to an elongated circular hole, and Figure 6B As shown, it can be a circular hole 121 with a radius "d" of 1.5 mm or more and 6 mm or less. Figure 6C As shown, the sound absorbing hole 111 may be a quadrilateral hole 131, one side of which is greater than 1.5 mm and less than 30 mm. When one side is greater than 30 mm, the strength and rigidity of the internal discharge cover 11 may not be maintained. However, as long as the strength and rigidity can be maintained to the extent that the internal discharge cover 11 will not be bent even if it is pressed from the outside, one side may be greater than 30 mm. In addition, it is preferred that the sound absorbing holes 111 as elongated circular holes, circular holes 121 or quadrilateral holes 131 are uniformly dispersed and arranged. In the first embodiment, the sound absorbing holes 111 as elongated circular holes, circular holes 121 or quadrilateral holes 131 are arranged at intervals "a" of 8 mm. In the portion of the internal discharge cover 11 that may contact the sheet S discharged from the discharge port 181, the sheet S may be stuck by the quadrilateral hole 131, so the shape of the sound absorbing hole 111 is preferably an elongated circular hole or a circular hole 121.

[0047] Figure 7 FIG. 1 is a cross-sectional view of the perforated surface 112 and the sound absorbing sheet 12 of the in-body discharge cover 11 in the first embodiment. Figure 7As shown, the sound absorbing hole 111 is inclined toward the discharge port 181 at an inclination angle θ relative to the surface of the in-body discharge cover 11. In the first embodiment, the sound absorbing hole 111 is inclined 30 degrees (θ=30 degrees) relative to the surface of the in-body discharge cover 11 in the direction of the discharge port 181. However, the inclination angle θ of the sound absorbing hole 111 relative to the surface of the in-body discharge cover 11 is not limited to 30 degrees. The inclination angle θ may be any angle, but it is preferred to set the inclination angle θ within a range of less than 45 degrees because the discharge port 181 and the in-body discharge cover 11 are arranged substantially at right angles when the main body of the image forming device 1 is observed from the upper side. In this case, the main body operation sound output from the discharge port 181 is likely to enter the sound absorbing hole 111, so the noise reduction effect can be further enhanced.

[0048] It is desirable that the percentage of the area occupied by the plurality of sound absorbing holes 111 relative to the surface area of ​​the portion of the main body (main body portion) corresponding to the perforated surface 112 and the plurality of sound absorbing holes 111 (the total area of ​​the back side of the main body in-body discharge space SP) is "35% or more". The reason for this is that when the percentage of the area occupied by the plurality of sound absorbing holes 111 is less than 35%, an effective sound absorbing effect cannot be obtained. When the percentage of the area occupied by the plurality of sound absorbing holes 111 is greater than 50%, generally speaking, the rigidity of the in-body discharge cover 11 made of resin is significantly reduced, and thus the effective rigidity of the in-body discharge cover 11 cannot be obtained. Therefore, the percentage of the area of ​​the plurality of sound absorbing holes 111 relative to the area of ​​the perforated surface 112 and the plurality of sound absorbing holes 111 (the total area of ​​the back side of the in-body discharge space SP) is preferably "35% or more and 50% or less". In the first embodiment, considering the processability of the sound absorbing holes 111 relative to the in-body exhaust cover 11 and the rigidity of the in-body exhaust cover 11, the percentage of the area occupied by the multiple sound absorbing holes 111 relative to the area of ​​the perforated surface 112 and the multiple sound absorbing holes 111 is greater than 35% and less than 50% per unit area.

[0049] As described above, according to the first embodiment, the following in-body discharge cover 11 is used, in which a plurality of sound absorbing holes 111 are formed and these sound absorbing holes 111 are covered with the sound absorbing sheet 12. Therefore, the main body operation sound output from the discharge port 181 can be reduced using a smaller space. That is, when a part of the main body operation sound output from the discharge port 181 passes through the sound absorbing hole 111 to diffuse in the sound absorbing sheet 12, part of the sound energy is converted into heat energy, so that the main body operation sound is reduced. In this way, according to the first embodiment, without using a Helmholtz resonator as in the prior art, a larger noise reduction effect can be obtained using a smaller space, so that the increase in the main body size of the image forming device 1 can be suppressed. According to the first embodiment, the size of the image forming device 1 can be prevented from increasing, and the propagation of the sound generated in the device and output from the discharge port to the outside of the device can be reduced. In the first embodiment, the sound absorbing structure formed by the sound absorbing sheet 12 and the in-body discharge cover 11 including the plurality of sound absorbing holes 111 is arranged on the back of the in-body discharge space SP. Therefore, the sound reflected at the back side toward the front side of the image forming apparatus 1 (the side where the user who operates the operation portion 10 stands) can be reduced, and thus this configuration is suitable for the user.

[0050] [Second embodiment]

[0051] Next, refer to Fig.10 The second embodiment is described. The configuration of the second embodiment is different from that of the first embodiment in that an in-body discharge cover 211 is provided at the upper portion of the in-body discharge space SP. However, the other configurations are similar to those of the first embodiment, and thus similar configurations are denoted by similar reference numerals to omit detailed description thereof.

[0052] Fig.10 is a cross-sectional view of an image forming apparatus 1 according to a second embodiment. Fig.10 As shown, the image forming device 1 has a structure in which an in-body discharge cover 211 having a plurality of sound absorbing holes 111 is provided on the upper side of the in-body discharge space SP. The in-body discharge cover 211 in the second embodiment defines the upper surface of the in-body discharge space SP. A sound absorbing device 213 formed by the in-body discharge cover 211 and the sound absorbing sheet 212 is mounted to the outer surface (lower surface) of the bottom plate (lower part) of the original reading section 41. In the second embodiment, the sound absorbing sheet (sound absorbing material) 212 is provided to abut against the in-body discharge cover 211, but the sound absorbing sheet 212 may be arranged to be separated from the in-body discharge cover 211.

[0053] When the sound absorbing holes 111 are covered with the sound absorbing sheet 212, part of the main body operation sound output from the discharge port 181 enters the sound absorbing sheet 212 through the sound absorbing holes 111. When the sound is greatly diffused in the sound absorbing sheet 212, part of the sound energy is converted into heat energy, so that the sound is reduced. The percentage of the area occupied by the plurality of sound absorbing holes 111 relative to the total area of ​​the bottom plate (lower surface) of the document reading unit 41 is preferably "35% or more and 50% or less".

[0054] The plurality of sound absorbing holes 111 and the sound absorbing sheet 212 may be provided in the entire region of the in-body discharge cover 211, or may be provided in a portion of the in-body discharge cover 211. The plurality of sound absorbing holes 111 and the sound absorbing sheet 212 may be provided in a plurality of portions of the in-body discharge cover 211. In addition, the plurality of sound absorbing holes 111 and the sound absorbing sheet 212 may be provided in a portion of the in-body discharge cover 211 on one side provided at the center position of the operation portion 10 relative to the direction orthogonal to the discharge direction A of the recording medium. According to the second embodiment, the size of the image forming apparatus 1 can be prevented from increasing, and the propagation of the sound generated in the apparatus and output from the discharge port to the outside of the apparatus can be reduced.

[0055] [Third embodiment]

[0056] Next, refer to Fig.11 The third embodiment is described. The configuration of the third embodiment is different from that of the first embodiment in that an in-body discharge cover 311 is provided in the discharge tray 19 serving as the bottom surface (bottom) of the in-body discharge space SP, and an in-body discharge cover 411 is provided in the discharge port surface 20 serving as the wall portion. However, other configurations are similar to those of the first embodiment, and thus similar configurations are denoted by similar reference numerals to omit detailed description thereof.

[0057] Fig.11 is a cross-sectional view of an image forming apparatus 1 according to a third embodiment. Fig.11As shown in FIG. 1 , the image forming apparatus 1 has a configuration in which an in-body discharge cover 311 including a plurality of sound absorbing holes 111 is provided on the lower side of the in-body discharge space SP, and an in-body discharge cover 411 including a plurality of sound absorbing holes 111 is provided in the wall portion where the discharge port 181 is provided. The in-body discharge cover 311 in the third embodiment defines the lower surface of the in-body discharge space SP. A sound absorbing device 313 formed by the in-body discharge cover 311 and the sound absorbing sheet 312 is mounted to the discharge tray 19 serving as a sheet stacking surface. In the third embodiment, the sound absorbing sheet (sound absorbing material) 312 is provided to abut against the in-body discharge cover 311, but the sound absorbing sheet 312 may be arranged to be separated from the in-body discharge cover 311. In the case where the sound absorbing holes 111 of the in-body discharge cover 311 are covered with the sound absorbing sheet 312, a part of the main body operation sound output from the discharge port 181 enters the sound absorbing sheet 312 through the sound absorbing holes 111. When sound is widely diffused in the sound absorbing sheet 312 , part of the sound energy is converted into heat energy, so that the sound is reduced. The percentage of the area occupied by the plurality of sound absorbing holes 111 relative to the total area of ​​the discharge tray 19 is desirably “35% or more and 50% or less”.

[0058] The in-body discharge cover 411 in the third embodiment defines the wall portion of the in-body discharge space SP. The sound absorbing device 413 formed by the in-body discharge cover 411 and the sound absorbing sheet 412 is mounted to the discharge port surface 20 formed with the discharge port 181. In the third embodiment, the sound absorbing sheet (sound absorbing material) 412 is set to abut against the in-body discharge cover 411, but the sound absorbing sheet 412 can be arranged to be separated from the in-body discharge cover 411. In the case where the sound absorbing hole 111 of the in-body discharge cover 411 is covered with the sound absorbing sheet 412, a part of the main body operation sound output from the discharge port 181 enters the sound absorbing sheet 412 through the sound absorbing hole 111. When the sound is greatly diffused in the sound absorbing sheet 412, part of the sound energy is converted into heat energy, so that the sound is reduced. The percentage of the area occupied by the plurality of sound absorbing holes 111 relative to the total area of ​​the discharge port surface 20 is expected to be "35% or more and 50% or less". In the third embodiment, both the in-machine body discharge covers 311 and 411 are disposed in the in-machine body discharge space SP, but only one of the in-machine body discharge cover 311 and the in-machine body discharge cover 411 may be disposed.

[0059] The sound absorbing structure may be arranged in any member facing the discharge space SP in the machine body. For example, the sound absorbing structure (sound absorbing device 313) may be arranged in the sheet stacking surface (discharge tray 19) (see Fig.11 ). In addition, a sound absorbing structure (sound absorbing device 413) may be arranged in the discharge port surface 20 forming the discharge port 181 (see Fig.11 ). In addition, the sound absorbing structure (sound absorbing device 13) may be arranged in the side surface of the exhaust space SP in the machine body (see Figure 4). In addition, the sound absorbing structure (sound absorbing device 213) may be arranged in the upper surface of the exhaust space SP in the machine body (see Fig.10 ).

[0060] The sound absorbing structure may be arranged in a plurality of surfaces facing the in-body discharge space SP. For example, the sound absorbing structure may be arranged in both the bottom plate of the manuscript reading section 41 and the back side of the in-body discharge space SP. In addition, the sound absorbing structure may be arranged in the bottom plate of the manuscript reading section 41, the back side of the in-body discharge space SP, and the sheet stacking surface (discharge tray 19). In addition, the sound absorbing structure may be arranged in the bottom plate of the manuscript reading section 41, the back side of the in-body discharge space SP, the sheet stacking surface (discharge tray 19), and the discharge port surface 20 forming the discharge port 181.

[0061] Even if a sound absorbing structure formed of the sound absorbing sheet 12 and the in-body discharge cover 11 including a plurality of sound absorbing holes 111 is mounted as a kit (ie, as an optional unit) to a portion facing the discharge space of the image forming apparatus, noise reduction can be achieved.

[0062] While the present disclosure has been described with reference to exemplary embodiments, it is to be understood that the present disclosure is not limited to the disclosed exemplary embodiments.The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An image forming device, comprising: an image forming section configured to form an image on a recording medium; a discharge port configured to discharge the recording medium on which the image is formed by the image forming section; a wall portion in which the discharge port is disposed; a bottom portion on which the recording medium discharged from the discharge port is to be stacked; an upper portion disposed opposite to the bottom portion; a side portion disposed along a discharge direction of the recording medium discharged from the discharge port; a discharge space defined by at least the wall portion, the bottom portion, the upper portion, and the side portion, wherein the discharge space accommodates the recording medium discharged from the discharge port; a plurality of through holes provided in at least any of the wall portion, the bottom portion, the upper portion, and the side portion; and A sound absorbing material is provided to cover the plurality of through holes on a side opposite to the discharge space with respect to at least a portion of the wall portion, the bottom portion, the upper portion, and the side portion in which the plurality of through holes are provided.

2. The image forming apparatus according to claim 1, in, The plurality of through holes are provided in the side portion, and The sound absorbing material is disposed on a side opposite to the discharge space with respect to the side portion.

3. The image forming apparatus according to claim 2, wherein: The plurality of through holes are provided in a portion of the side portion.

4. The image forming apparatus according to claim 2, wherein: A percentage of an area occupied by the plurality of through holes relative to an area of ​​the side portion is 35% or more and 50% or less per unit area.

5. The image forming apparatus according to claim 1, in, The plurality of through holes are provided in the upper portion, and The sound absorbing material is disposed on a side opposite to the discharge space with respect to the upper portion.

6. The image forming apparatus according to claim 5, further comprising an operation portion to be operated by a user, in, The plurality of through holes are provided in a portion of the upper portion on a side where the operation portion is provided.

7. The image forming apparatus according to claim 1, further comprising another side portion disposed opposite to the side portion, in, The plurality of through holes are provided in the other side portion, or in both the side portion and the other side portion, wherein the sound absorbing material is disposed on a side opposite to the exhaust space relative to the other side portions, and Wherein, in a case where the plurality of through holes are provided in the side portion, the sound absorbing material is provided on a side opposite to the discharge space with respect to the side portion.

8. The image forming apparatus according to any one of claims 1 to 7, wherein: The sound absorbing material has a sheet shape.

9. The image forming apparatus according to any one of claims 1 to 7, in, The sound absorbing material is formed into a sheet shape having any one of EPDM-based foam or polyurethane-based foam, glass wool material, and rock wool, and The sound absorbing material abuts against at least the portion of the wall portion, the bottom portion, the upper portion, and the side portion where the plurality of through holes are provided.

10. The image forming apparatus according to any one of claims 1 to 7, wherein: The plurality of through holes have circular holes with a radius of 1.5 mm to 6 mm, or elongated circular holes with a radius of 1.5 mm to 6 mm and a width of 3 mm to 30 mm.

11. The image forming apparatus according to any one of claims 1 to 7, wherein: The plurality of through holes have quadrilateral holes with a side of 1.5 mm or more and 30 mm or less.

12. The image forming apparatus according to any one of claims 1 to 7, wherein: The plurality of through holes are inclined toward the wall portion.

13. The image forming apparatus according to any one of claims 1 to 7, wherein: The sound absorbing material is bonded to a portion among the wall portion, the bottom portion, the upper portion, and the side portion by an adhesive member.

14. The image forming apparatus according to any one of claims 1 to 7, in, A portion of the wall portion, the bottom portion, the upper portion and the side portion is provided with a joint portion, The sound absorbing material is provided with a joined portion, and The engaged portion of the sound absorbing material is engaged with the engaging portion of a portion of the wall portion, the bottom portion, the upper portion, and the side portion where the plurality of through holes are provided.

15. The image forming apparatus according to any one of claims 1 to 7, further comprising a reader disposed above the discharge space and configured to read an image of a document, in, The reader includes the upper portion.

16. An image forming apparatus, comprising: an image forming section configured to form an image on a recording medium; a discharge port configured to discharge the recording medium on which the image is formed by the image forming section; a discharge space in which the recording medium discharged from the discharge port is to be accommodated in a stacked state; a member facing the discharge space and defining the discharge space; a plurality of through holes disposed in the member; as well as A sound absorbing material is provided to cover the plurality of through holes on a side of the member opposite to the exhaust space.

17. The image forming apparatus according to claim 16, wherein: The member provided with the plurality of through holes is a side portion provided along a discharge direction of the recording medium discharged from the discharge port.

18. The image forming apparatus according to claim 16, further comprising: a bottom portion on which the recording medium discharged from the discharge port is to be stacked, Wherein, the member provided with the plurality of through holes is arranged to be opposite to the bottom.

19. The image forming apparatus according to claim 16, wherein: The member provided with the plurality of through holes is a bottom portion on which recording media discharged from the discharge port are to be stacked.

20. The image forming apparatus according to claim 16, wherein: The member provided with the plurality of through holes is a wall portion provided with the discharge port.

21. The image forming apparatus according to any one of claims 16 to 20, wherein: The sound absorbing material has a sheet shape.

Images