JP6172009B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus that forms an image on a sheet.

  For example, in the invention described in Patent Document 1, in order to reduce noise generated from a plate made of a metal plate to which an electric motor is fixed, a portion of the plate that vibrates with the largest amplitude with vibration of the electric motor. A large number of through holes are provided.

JP 2009-9016 A

  However, in the invention described in Patent Document 1, since a large number of through holes are provided in the plate, the plate cannot function as a sound insulating wall. That is, the noise generated on one side of the plate passes through the through hole and reaches the other side of the plate.

  In view of the above points, an object of the present invention is to reduce noise with a novel configuration different from the invention described in Patent Document 1.

  In order to achieve the above object, the present invention provides an electric motor (23) and a metal plate plate (21) to which the electric motor (23) is fixed in an image forming apparatus for forming an image on a sheet. The plate (21) having a through hole (21A) penetrating the plate (21), and a position shifted in a direction perpendicular to the plate surface of the plate (21) with respect to the through hole (21A). A cover part (21B) formed by bending a part of a metal plate, and the cover part (21B) projected on a virtual plane parallel to the plate surface is projected on the virtual plane It is located in the made through-hole (21A).

  Accordingly, in the present invention, the resonance region of the plate (21) is shifted by the through hole (21A) provided in the plate (21) and the occurrence of resonance is suppressed, so that the plate (21) vibrates with a large amplitude. This can be suppressed.

  Furthermore, even if the plate (21) is vibrated by the electric motor (23), the area where the plate (21) pushes the air is reduced, so that the vibration of the air is reduced and noise can be reduced.

  And since the cover part (21B) projected on the virtual surface is located in the through hole (21A) projected on the virtual surface, at least a part of the through hole (21A) becomes the cover part (21B). And covered. For this reason, it can suppress that the noise generated on one side of the plate (21) passes through the through hole (21A) and reaches the other side of the plate (21).

As described above, in the present invention, it is possible to reduce the noise accompanying the vibration of the plate (21) and the noise passing through the through hole (21A) and reaching the other side of the plate (21).
Incidentally, the reference numerals in parentheses for each of the above means are examples showing the correspondence with the specific means described in the embodiments described later, and the present invention is indicated by the reference numerals in the parentheses of the above respective means. It is not limited to specific means.

1 is a central sectional view of an image forming apparatus according to an embodiment of the present invention. It is a perspective view showing the relation with electric motors 23, such as frame 20 and plate 21, in a 1st embodiment of the present invention. It is a figure which shows the positional relationship etc. of the electric motor 23, cover part 21B, etc. in 1st Embodiment of this invention. It is AA sectional drawing of FIG. (A) And (b) is a figure which shows the cover part 21B which concerns on 2nd Embodiment of this invention. (A) And (b) is a figure which shows the cover part 21B which concerns on 3rd Embodiment of this invention.

  The “embodiment of the invention” described below shows an example of the embodiment. In other words, the invention specific items described in the claims are not limited to the specific means and structures shown in the following embodiments.

In this embodiment, the present invention is applied to a monochrome image forming apparatus. Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In addition, the arrow etc. which show the direction attached | subjected to each figure were described in order to make it easy to understand the relationship between each figure, and this invention is not limited to the direction attached | subjected to each figure. Absent. At least one member or part described with at least a reference numeral is provided, except where “plurality”, “two or more”, and the like are omitted.

(First embodiment)
1. Outline of Image Forming Apparatus As shown in FIG. 1, an image forming unit 5 that forms an image on a sheet is accommodated in a housing 3 of the image forming apparatus 1. The image forming unit 5 is an electrophotographic system having a developing cartridge 7, a photosensitive drum 8, an exposure device 9, a fixing device 11, and the like.

  A discharge port 3 </ b> A and a discharge tray 3 </ b> B are provided at the top of the housing 3. The discharge port 3A is a portion where a sheet on which an image is formed is discharged. The discharge tray 3B is a placement unit on which the sheet discharged from the discharge port 3A is placed.

  The developing cartridge 7 includes a developing roller 7A, a storage portion 7B, and the like. The photosensitive drum 8 carries a developer image. The charger 8A charges the photosensitive drum 8. The exposure device 9 exposes the charged photosensitive drum 8. Thereby, an electrostatic latent image is formed on the photosensitive drum 8.

  The developing roller 7A supplies the developer stored in the storage unit 7B to the photosensitive drum 8. As a result, a developer image is formed on the photosensitive drum 8. A transfer unit 13 is disposed at a position facing the photosensitive drum 8.

  The transfer unit 13 transfers the developer image carried on the photosensitive drum 8 to a sheet. The fixing device 11 directly or indirectly heats the developer transferred to the sheet, and fixes the developer image on the sheet.

  The first feeder mechanism 15 sends out the sheets placed on the paper feed tray 17 one by one toward the image forming unit 5 side. The second feeder mechanism 19 sends out the sheets placed on the multipurpose sheet feeding tray (not shown) one by one toward the image forming unit 5 side.

  The paper feed tray 17 is detachably attached to the apparatus main body below the image forming unit 5 in the apparatus main body. The apparatus main body refers to a portion that is not disassembled by the user, such as the housing 3 and the frame 20 (see FIG. 2).

  As shown in FIG. 2, the frame 20 includes a pair of plate-like members 20A and 20B formed of resin or metal. The pair of plate-like members 20A and 20B are connected by at least one connecting frame 20C in a state of being spaced apart from each other. The image forming unit 5 and the paper feed tray 17 are disposed between the pair of plate-like members 20A and 20B.

  An electric motor 23 is disposed on either one of the pair of plate-like members 20A and 20B (in this embodiment, the plate-like member 20A). The electric motor 23 is disposed on the opposite side of the image forming unit 5 across the plate-like member 20A, that is, between the frame 20 and a side cover (not shown).

  The side cover is a member that covers a side surface of the frame 20 and constitutes a part of the housing 3 and constitutes an external design surface of the image forming apparatus 1. For this reason, the electric motor 23 will be in the state covered with the side cover.

  The electric motor 23 is assembled and fixed to a plate 21 made of a metal plate such as SPCC or SECC. The electric motor 23 is provided with a motor flange (not shown) for assembly. The electric motor 23 is assembled and fixed to the plate 21 with screws (not shown) through the motor flange.

  As shown in FIG. 3, the outer shape of the plate 21 is formed in a polygonal shape (in this embodiment, a rectangular shape), and is fixed to the frame 20 (the plate-like member 20A) with a fastening member such as a screw 25A. Has been.

  As shown in FIG. 4A, the output shaft 23A of the electric motor 23 protrudes toward the frame 20 side. A rotating body 23B for transmitting a driving force such as a gear or a pulley is assembled to the output shaft 23A. The rotating body 23B according to the present embodiment is a gear.

  A gear train 23C is provided between the plate 21 and the frame 20 to transmit the driving force generated by the electric motor 23 to the photosensitive drum 8, the heating roller 11A (see FIG. 1) of the fixing device 11, and the like. .

2. As shown in FIG. 4A, the cover 21 for reducing vibration is provided with at least one through hole 21A (9 in this embodiment) penetrating the plate 21 in the thickness direction. A part of each through hole 21A is covered with a cover portion 21B as shown in FIG.

  That is, as shown in FIG. 4A, each cover portion 21 </ b> B is displaced in a direction perpendicular to the plate surface 21 </ b> C of the plate 21 (left and right direction in the present embodiment) with respect to the through hole 21 </ b> A. Is provided. For this reason, as shown in FIG. 3, the cover part 21B projected on the virtual surface parallel to the plate surface 21C is located in the through hole 21A projected on the virtual surface.

  The cover portion 21B according to the present embodiment is formed by cutting and raising a part of the metal plate constituting the plate 21 and bending it into a substantially L shape, as shown in FIG. 4 (a). is there. For this reason, as shown in FIG. 3, the cover portion 21 </ b> B is accommodated in the inner edge of the through hole 21 </ b> A and covers a part of the through hole 21 </ b> A.

  As shown in FIG. 4A, the cover portion 21B is located on the opposite side of the image forming portion 5 with the plate 21 interposed therebetween. That is, the image forming unit 5 is provided on one side of the plate 21 and the cover unit 21B is provided on the other side of the plate 21.

  In the present embodiment, the boundary portion 21D between the cover portion 21B and the plate 21 is located closer to the electric motor 23 than the tip 21E of the cover portion 21B, and the boundary portion 21D is a cover portion as shown in FIG. It is located vertically above the tip 21E of 21B.

  And as shown in FIG.4 (b), the horizontal direction dimension W1 in the boundary part 21D among the cover parts 21B is a dimension larger than the vertical dimension W2 of the cover part 21B. Note that the vertical direction refers to the direction from the boundary 21D toward the tip 21E. The horizontal direction is a direction perpendicular to the vertical direction and the thickness direction.

3. Features of the Image Forming Apparatus According to the Present Embodiment In this embodiment, since the resonance region of the plate 21 is shifted by the through hole 37 provided in the plate 21 and the resonance with the electric motor 23 is suppressed, the plate 21 is It is possible to suppress vibration with a large amplitude.

  Further, even if the plate 21 is vibrated by the electric motor 23, the area where the plate 21 pushes the air is reduced, so that the vibration of the air is reduced and noise can be reduced.

  As shown in FIG. 3, since at least a part of the through hole 37 is covered with the cover portion 21 </ b> B, noise generated on one side of the plate 21 passes through the through hole 37 and the other side of the plate 21. It can suppress reaching the side.

  Therefore, in this embodiment, the noise accompanying the vibration of the plate 21 and the noise passing through the through hole 37 and reaching the other side of the plate 21 can be reduced. Note that it is effective to provide the through hole 21A and the cover portion 21B in a portion of the plate 21 that is likely to be displaced with the largest amplitude due to the vibration of the electric motor 23.

  As shown in FIG. 4, the boundary 21 </ b> D between the cover 21 </ b> B and the plate 21 is positioned closer to the electric motor 23 than the tip 21 </ b> E of the cover 21 </ b> B, so that the tip 21 </ b> E is closer to the electric motor 23. The vibration generated by the electric motor 23 is easily transmitted to the cover portion 21B. For this reason, it is expected that the viscous friction between the cover portion 21B and the air increases with the vibration of the cover portion 21B, and the vibration of the plate 21 is attenuated.

  As shown in FIG. 3, the boundary portion 21D between the cover portion 21B and the plate 21 is located on the upper side in the vertical direction from the tip 21E of the cover portion 21B. For this reason, in this embodiment, since the upper side in the vertical direction of the through hole 21A is closed, the noise emitted from the through hole 21A is difficult to diffuse upward in the vertical direction.

  At this time, since the position of the user's ear is usually positioned on the upper side in the vertical direction from the image forming apparatus 1, the noise emitted from the through hole 21A is difficult to reach the user's ear. Can be reduced.

  Since the horizontal dimension W1 of the cover part 21B is larger than the vertical dimension W2, the natural frequency of the cover part 21B can be increased as compared with the case where the horizontal dimension W1 is smaller than the vertical dimension W2. Therefore, since the resonance of the cover portion 21B can be suppressed, the generation of new noise due to the resonance of the cover portion 21B can be suppressed.

(Second Embodiment)
The cover portion 21B according to the first embodiment has a flat plate shape, but the cover portion 21B according to the present embodiment is a portion facing at least the through hole 21A in the cover portion 21B as shown in FIG. Is curved. Incidentally, the vertical dimension W2 shown in FIG. 5A means a length measured in the vertical direction along the curved cover portion 21B.

  And the cover part 21B has the 1st inclination part 21F and the 2nd inclination part 21G, and is curving so that it may become convex in the shift | offset | difference direction of the cover part 21B, as shown in FIG.5 (b). That is, the cover portion 21B is convex toward the side cover side so that the boundary portion 21H between the first inclined portion 21F and the second inclined portion 21G becomes the top of the curve.

  The first inclined portion 21F is a portion connected to the boundary portion 21D in the cover portion 21B, and is inclined with respect to the plate surface 21C so as to be separated from the through hole 21A toward the tip 21E side, that is, the boundary portion 21H. It is a part. The second inclined portion 21G is a portion that extends from the boundary portion 21H to the tip 21E side of the first inclined portion 21F, and is a portion that is inclined in the direction opposite to the first inclined portion 21F with respect to the plate surface 21C.

  Thereby, in this embodiment, it becomes possible to reflect so that the noise (sound wave) which collided with the cover part 21B through the through-hole 21A may be diffused in various directions. Therefore, it is possible to reduce the noise actually heard by the user.

Furthermore, in this embodiment, since the cover part 21B is curved so as to be convex in the shifting direction of the cover part 21B, the cover part 21B can be easily formed.
In addition, although the 1st inclination part 21F and 2nd inclination part 21G which concern on this embodiment are comprised by the so-called two-dimensionally curved curved surface curved only in the vertical direction, this embodiment is the cover part 21B. It only needs to be curved as a whole.

  Therefore, for example, when the first inclined part 21F and the second inclined part 21G are configured by flat inclined surfaces, or the first inclined part 21F and the second inclined part 21G are curved in the vertical direction and the horizontal direction. A so-called three-dimensional curved surface may be used.

(Third embodiment)
This embodiment is a modification of the second embodiment. That is, as shown in FIG. 6A, the covering portion 21B according to the present embodiment is a so-called three-dimensionally curved curved surface (for example, a spherical shape) in which the covering portion 21B is curved in the vertical direction and the horizontal direction. It is configured.

  Thereby, in this embodiment, since the rigidity of the cover part 21B can be improved, it can suppress that the cover part 21B resonates and a new noise is generated, and noise (sound wave) that collides with the cover part 21B. Can be reflected so as to diffuse in various directions.

In addition, in the cover part 21B which concerns on this embodiment, although the site | part corresponded to the 2nd inclination part 21G is not provided, you may provide the 2nd inclination part 21G similarly to 2nd Embodiment.
(Other embodiments)
In the second and third embodiments, the cover portion 21B is curved so as to be convex in the displacement direction of the cover portion 21B, but the present invention is not limited to this, and the displacement direction of the cover portion 21B The cover portion 21B may be curved so as to be convex in the opposite direction.

  In the above-described embodiment, the through hole 21A and the cover portion 21B are provided in a portion of the plate 21 that is likely to be displaced with the largest amplitude due to the vibration of the electric motor 23. However, the present invention is limited to this. Instead, other portions, for example, near the centroid of the plate 21 may be provided. The centroid is a position where the area moments are balanced on the plate surface of the plate 21.

  In the above-described embodiment, the plurality of through holes 21A and the plurality of cover portions 21B are provided. However, the present invention is not limited to this, and for example, one through hole 21A and one cover portion 21B may be provided. .

  In the above-described embodiment, the cover portions 21B are provided in all the through holes 21A. However, the present invention is not limited to this. For example, the through holes 21A in which the cover portions 21B are not provided, and the cover portions 21B. 21 A of through-holes provided with may be mixed.

  The electric motor 23 according to the above-described embodiment supplies driving force to a rotating body such as the photosensitive drum 8, but the present invention is not limited to this. For example, the polygon of a scanning exposure device is used. An electric motor that rotates the mirror may be used.

  Although the plate 21 according to the above-described embodiment has a rectangular shape, the present invention is not limited to this, and may be, for example, a triangular shape, a concave polygon, or a shape surrounded by a smooth curve. May be.

  The image forming unit 5 according to the above-described embodiment is a monochrome electrophotographic method, but the present invention is not limited to this, and is a color electrophotographic or ink jet type image forming unit 5. Also good.

  Further, the present invention is not limited to the above-described embodiment as long as it matches the gist of the invention described in the claims. Therefore, you may combine at least 2 embodiment among 1st-3rd embodiment. That is, the cover part 21B according to the first to third embodiments may be mixed.

DESCRIPTION OF SYMBOLS 1 ... Image forming apparatus 3 ... Housing | casing 3A ... Discharge port 3B ... Discharge tray 5 ... Image formation part 7 ... Developing cartridge 7A ... Developing roller 7B ... Storage part 8 ... Photosensitive drum 8A ... Charger 9 ... Exposure device 11 ... Fixing device DESCRIPTION OF SYMBOLS 11A ... Heating roller 13 ... Transfer part 15 ... 1st feeder mechanism 17 ... Paper feed tray 19 ... 2nd feeder mechanism 20 ... Frame 20A ... Plate-shaped member 20C ... Connection frame 21 ... Plate 21A ... Through-hole 21B ... Cover part 21C ... Plate surface 21D ... Boundary portion 21E ... Tip 21F ... First inclined portion 21G ... Second inclined portion 21H ... Boundary portion 23 ... Electric motor 23A ... Output shaft 23B ... Rotating body 23C ... Gear train 37 ... Through hole W1 ... Horizontal dimension W2 ... Vertical dimension

Claims (9)

In an image forming apparatus for forming an image on a sheet,
An electric motor;
A plate made of a metal plate to which the electric motor is fixed, and a plate having a through hole penetrating the plate;
A cover portion provided at a position shifted in a direction perpendicular to the plate surface of the plate with respect to the through hole, wherein the cover portion is formed by bending a part of the metal plate. ,
The image forming apparatus according to claim 1, wherein the cover portion projected onto a virtual surface parallel to the plate surface is located in the through hole projected onto the virtual surface.   The image forming apparatus according to claim 1, wherein at least a portion of the cover facing the through hole is curved. The covering portion is
A first inclined portion connected from a boundary portion with the plate, the first inclined portion inclined with respect to the plate surface so as to be separated from the through hole toward the tip side, and from the first inclined portion 3. The image forming apparatus according to claim 2, wherein the image forming apparatus includes a second inclined portion that reaches the leading end side and is inclined in a direction opposite to the first inclined portion with respect to the plate surface.   The image forming apparatus according to claim 2, wherein the cover is curved in a spherical shape.   The image forming apparatus according to claim 2, wherein the cover portion is curved so as to be convex in a shift direction of the cover portion. An image forming unit for forming an image on a sheet;
The image forming apparatus according to claim 1, wherein the image forming unit is provided on one side of the plate, and the cover unit is provided on the other side of the plate. When the direction from the boundary between the cover and the plate toward the tip of the cover is the vertical direction, and the direction perpendicular to the vertical direction and the thickness direction is the horizontal direction,
The image forming apparatus according to claim 1, wherein a horizontal dimension of the covering portion is larger than a vertical dimension.   8. The image forming apparatus according to claim 1, wherein a boundary portion between the cover portion and the plate is positioned above the front end of the cover portion in the vertical direction.   The image forming apparatus according to claim 1, wherein a boundary portion between the cover portion and the plate is located closer to the electric motor than a tip end of the cover portion.

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