Image forming apparatus

Abstract

To prevent an inner cover from coming off in transporting an apparatus.SOLUTION: An image forming apparatus includes: a housing; a first cover that is rotatably supported around a first rotary shaft portion relative to the housing and has a placement portion for placing a sheet; a regulation portion that is movably provided relative to the first cover and regulates a position of the sheet placed on the first cover; and a second cover that is rotatably supported relative to the housing around a second rotary shaft portion different from the first rotary shaft portion and covers an upper portion of the sheet placed on the placement portion in a state where the first cover is opened. The regulation portion and the second cover have an engagement portion for engaging with each other at a predetermined position to regulate movement relative to the placement portion. The second cover comes into contact with the regulation portion before the second cover comes off from the housing by regulating the regulation portion with the second cover at the predetermined position in a position at which the first cover and the second cover are closed relative to the housing.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to image forming apparatuses such as copiers, printers, facsimiles, and the like.

Background Art

[0002] Conventionally, there has been known an image forming apparatus having a sheet placement portion for opening an openable outer cover provided on a side surface of the image forming apparatus and placing a sheet inside the outer cover. Patent Document 1 discloses a configuration including a rotatable inner cover in order to prevent adhesion of dust or the like to the sheet surface placed on the outer cover. Further, the outer cover and the inner cover each have a rotation shaft portion for opening and closing at both axial ends, and are rotatably supported with respect to the housing of the image forming apparatus main body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, weight reduction and workability of image forming apparatuses have been demanded, and the inner cover needs to be thinned and the assemblability to the housing needs to be simplified. On the other hand, in the transportation of the image forming apparatus main body, as the weight of the apparatus becomes lighter, there are more risks of collision during apparatus transportation and dropping of the apparatus. In this case, when the inner cover and the outer cover are closed, there is a risk that the rotation shaft portion of the inner cover comes off from the support portion of the housing due to an impact caused by a collision or dropping.

[0005] Therefore, an object of the present invention is to reduce the detachment of the inner cover from the support portion of the apparatus main body even when the outer cover and the inner cover are in a closed position with respect to the apparatus main body.

Means for Solving the Problems

[0006] An image forming apparatus according to one aspect of the present invention comprises a housing; a first cover supported so as to be openable and rotatable with respect to the housing and rotatable about a first pivot axis, and having a mounting portion on which a sheet is placed; a regulating portion provided so as to be movable with respect to the first cover and regulating the position of the sheet placed on the mounting portion; and a second cover supported so as to be openable and rotatable with respect to the housing and rotatable about a second pivot axis different from the first pivot axis, and covering the upper part of the sheet placed on the mounting portion when the first cover is open, wherein the regulating portion has engaging portions that engage with each other at a predetermined position to restrict movement with respect to the first cover, and the second cover abuts against the regulating portion before the second pivot axis of the second cover disengages from the housing when the regulating portion is restricted by the engaging portions to the first cover at the predetermined position and the first cover is closed with respect to the housing. [Effects of the Invention]

[0007] According to the present invention, it is possible to reduce the detachment of the inner cover from the pivot shaft support during the transportation of the device. [Brief explanation of the drawing]

[0008] [Figure 1] Cross-sectional view of the image forming apparatus in Embodiment 1 [Figure 2] External view of the image forming apparatus in Embodiment 1 with the outer cover in the closed position. [Figure 3] External view of the image forming apparatus in the open position of the outer cover in Embodiment 1 [Figure 4] Partial detail view of the outer cover in the open position in Embodiment 1 [Figure 5] A partial cross-sectional view (a) and a perspective view (b) of the outer cover in the closed position in Embodiment 1. [Figure 6] Partial detail view of the regulatory section and outer cover in Embodiment 1 [Figure 7] A partial cross-sectional view (a) and a perspective view (b) of the outer cover in the closed position in Embodiment 2. [Modes for carrying out the invention]

[0009] The embodiments for carrying out the invention will be described in detail below with reference to the drawings.

[0010] [Embodiment 1] <Image forming apparatus> Figure 1 is a schematic cross-sectional view of the image forming apparatus 100 according to this embodiment. The image forming apparatus 100 includes a feeding unit 101 at the bottom for feeding sheets, an image forming unit 102 in the middle for forming images on the sheets, and a discharge unit 103 at the top for discharging the sheets on which images have been formed.

[0011] The image forming apparatus 100 of this embodiment is an electrophotographic full-color printer equipped with yellow, magenta, cyan, and black image forming units Pa, Pb, Pc, and Pd along an intermediate transfer belt 15. The image forming apparatus 100 can receive image data from an external device (not shown), such as a USB memory stick or a personal computer, and form a toner image on a recording material P based on the received image data. Various types of sheet materials can be used as the recording material P, such as plain paper, cardboard, rough paper, textured paper, coated paper, plastic film, or cloth.

[0012] In this embodiment, the intermediate transfer section 60 is provided below the image forming sections Pa to Pd. The intermediate transfer section 60 is configured such that an endless intermediate transfer belt 15 is stretched over a plurality of rollers (31, 32, 33) and rotates and moves in the direction of arrow R1. A secondary transfer outer roller 16 is provided at a position opposite the roller 31 that stretches the intermediate transfer belt 15, and forms a secondary transfer section N2 that transfers the toner image carried on the intermediate transfer belt 15 to the recording material P. The secondary transfer section N2 is a transfer nip section formed by the roller 31 and the secondary transfer outer roller 16, and the toner image is secondary transferred onto the recording material P in response to, for example, the application of a secondary transfer voltage to the secondary transfer outer roller 16 by a power supply (not shown).

[0013] Next, the image forming process by which the image forming apparatus 100 forms a four-color full-color image will be described. However, the four image forming sections Pa to Pd of the image forming apparatus 100 have substantially the same configuration except for the difference in development color. Therefore, the black image forming section Pd will be described here, and the other image forming sections Pa to Pc will be omitted from the description.

[0014] The image forming unit Pd has a photosensitive drum 10d as a photoreceptor. The photosensitive drum 10d is rotated in the direction of arrow R2 by a drum drive motor (not shown). A charging device 11d, a developing device 12d, a primary transfer roller 14d, and a cleaning device 13d are provided around the photosensitive drum 10d.

[0015] When the operation of image formation is started, the surface of the rotating photosensitive drum 10d is uniformly charged by the charging device 11d. Next, the surface of the charged photosensitive drum 10d is exposed by the laser beam Ld corresponding to the image signal emitted from the exposure device 2. Thereby, an electrostatic latent image corresponding to the image signal is formed on the photosensitive drum 10d. The electrostatic latent image formed on the photosensitive drum 10d is developed into a toner image by the developer accommodated in the developing device 12d. In the case of this embodiment, one exposure device 2 is provided above the image forming units Pa to Pd, and a plurality of photosensitive drums 10a to 10d are exposed by only one exposure device 2. That is, one exposure device 2 is shared by a plurality of image forming units Pa to Pd for exposure.

[0016] The toner image formed on the photosensitive drum 10d is primarily transferred to the intermediate transfer belt 15 at the primary transfer portion N1d formed between the primary transfer rollers 14d arranged sandwiching the intermediate transfer belt 15. At this time, a primary transfer voltage is applied to the primary transfer roller 14d by a power source not shown. The intermediate transfer belt 15 carries the toner image transferred from the photosensitive drum 10d. In addition, the attachments such as toner remaining on the surface of the photosensitive drum 10d after primary transfer are removed by the cleaning device 13d.

[0017] Such operations are sequentially performed in the respective image forming units Pa to Pd of yellow, magenta, cyan, and black, and the four-color toner images are superimposed on the intermediate transfer belt 15. Thereafter, the recording material P accommodated in the cassette 40 is conveyed to the secondary transfer portion N2 in accordance with the formation timing of the toner image. The above is the image forming process for forming an image.

[0018] Next, a sheet conveyance process for transferring the image formed according to the image forming process to the recording material P will be described. Below the image forming apparatus 100, a feeding unit 101 for feeding the recording material P is provided. The feeding unit 101 mainly includes a cassette 40 for accommodating the recording material P, and a feeding roller 901 for feeding the recording material accommodated in the cassette 40. The feeding roller 901 feeds the recording material P placed on the cassette 40 toward the registration roller 902. The registration roller 902 corrects the skew of the recording material P and conveys the recording material P to the secondary transfer unit N2 in synchronization with the toner image on the intermediate transfer belt 15. Then, in response to the application of a secondary transfer voltage by a power source (not shown) to the secondary transfer outer roller 16, the toner image on the intermediate transfer belt 15 is secondarily transferred onto the recording material P.

[0019] Thereafter, the recording material P onto which the toner image has been secondarily transferred is conveyed to the fixing device 50. The fixing device 50 heats and pressurizes the recording material P while conveying it to fix the toner image on the recording material P. The recording material P on which the toner image has been fixed by the fixing device 50 is conveyed upward and loaded onto the discharge tray 5 of the discharge unit 103. The discharge unit 103 has a first roller 71 and a second roller 72 as a pair of conveyance rollers. The first roller 71 and the second roller 72 are in contact with each other to form a discharge nip portion N3 capable of sandwiching and conveying the recording material P, and discharge the recording material P obliquely upward. The image forming apparatus 100 in the present embodiment is configured such that the above-described image forming process and sheet conveyance process interact with each other.

[0020] In addition, in the present embodiment, an image forming unit 300 for forming a toner image on the recording material P is configured by the above-described image forming portions Pa to Pd, the intermediate transfer portion 60, the secondary transfer outer roller 16, and the like. Then, the above-described exposure device 2, image forming unit 300, fixing device 50, feeding roller 901, registration roller 902, discharge unit 70, and cassette 40 are accommodated in the image forming apparatus 100 and attached to a housing constituting the frame of the image forming apparatus.

[0021] <Opening / Closing and Support Configuration of Cover> Next, the opening and closing configuration of the cover in this embodiment will be described with reference to Figures 1, 2, and 3. As shown in Figures 2 and 3, the outer cover 108 provided on the side of the image molding apparatus 100 can be opened forward to access the feeding unit 101. When the outer cover 108 is closed, it is in an upright position and covers the feeding unit 101. When the outer cover 108 is open, it is in a nearly horizontal position.

[0022] When the image forming apparatus 100 is not in use or during transport, the outer cover 108 is closed as shown in Figure 2. The outer surface of the outer cover 108 is the exterior surface of the image forming apparatus 100. On the other hand, the inner surface of the outer cover 108 is the mounting section 102 on which the sheet P is placed. When the outer cover 108 is open and in a horizontal position, the top surface of the outer cover 108 becomes the mounting section 102.

[0023] Furthermore, when using the image forming apparatus 100, if dust or other debris accumulates on the mounting section 102 or on the sheet P placed on the mounting section 102, the dust is transported along with the sheet P. If dust enters the image forming section 102, it may cause problems such as distortion of the image printed on the sheet P. To suppress the occurrence of such problems, a dustproof cover 202, which is an inner cover that covers the mounted sheet P, is provided. The dustproof cover 202 can rotate between a nearly horizontal position that covers the upper surface of the sheet P placed on the mounting section 102 and an upright position when the outer cover 108 is open. When the outer cover 108 is opened from the closed position to the open position, the dustproof cover 202 also moves from the closed position to the open position due to its own weight.

[0024] Next, with reference to Figures 4 and 5, the support configuration for opening and closing the cover of the image forming apparatus 100 will be described. Figure 4 is a detailed view of the outer cover and inner cover in the open position. Figure 5(a) is a cross-sectional view of the inner cover and the vicinity of the outer cover when the outer cover is in the closed position. Figure 5(b) is a perspective view of Figure 5(a). As shown in Figure 5(b), the outer cover 108 has first pivot shafts 109 formed at both ends of the lower edge when it is in an upright position. The first pivot shafts 109 are pivotally supported by engaging with holes (not shown) provided in the housing. Similarly, when the dust cover 202 is in an upright position, second pivot shafts 203 are formed at both ends of the lower edge of the dust cover 202. The second pivot shafts 203 are pivotally supported by engaging with holes (not shown) provided in the housing of the image forming apparatus 100, which are different from the holes into which the first pivot shafts 109 are engaged.

[0025] Furthermore, as shown in Figure 5(a), the second pivot axis 203 of the dust cover 202 is positioned inward in the width direction of the image forming apparatus body compared to the first pivot axis 109 of the outer cover 108. This allows the dust cover 202 to be stored further inside the apparatus than the outer cover 108 when the outer cover 108 is closed. This is because when the operator places the sheet P on the mounting section 102 with the outer cover 108 open, the dust cover 202 is retracted to an upright position. At that time, the part of the dust cover 202 that has rotated must not enter the mounting area of ​​the sheet 106. If the part of the dust cover 202 enters the mounting area of ​​the sheet P, it will hinder the placement of the sheet P. Therefore, the second pivot axis 203 of the dust cover 202 needs to be positioned vertically above the area on which the sheet P is placed. If the second pivot axis 203 of the dust cover 202 is located below the highest point of the area on which the sheet P is placed, then when the dust cover 202 is in an upright position, a portion of the dust cover 202 near its pivot center will intrude into the area on which the sheet P is placed. Also, if the portion of the cover that intrudes into the area on which the sheet P is placed is removed, when the dust cover 202 is in a position to cover the sheet P on which it is placed, the removed portion will not be able to cover part of the sheet P, and the dustproof function will be impaired. Depending on the size of the main body of the device and the size of the mounting section 102, it may be difficult to cover the entire sheet P with a single dust cover 202. In that case, the dust cover 202 may be configured to be divided into two or more sections, one on the front side and one on the rear side in the sheet transport direction D.

[0026] <Restrictive section that controls the rear end of the seat> Figure 4 shows a detailed view of the sheet P when it is set on the mounting section 102 in Figure 3. The mounting section 102 is equipped with a regulating section 200 for regulating the position of the mounted sheet P. The regulating section 200 regulates the side of the rear end in the sheet transport direction D and has the function of suppressing disturbances in the position of the mounted sheet P caused by the operation and vibration of the feed rollers 901 and other components when the device is in use.

[0027] Furthermore, the restricting section 200 is attached to the mounting section 102 of the outer cover 198 and is provided to be movable in the sheet transport direction D and the opposite direction. The restricting section 200 is movable to a position that restricts the rear end of the sheet P, according to the length of the sheet P in the transport direction when it is placed on the mounting section 102. In addition, the restricting section 200 is positioned approximately in the center in the width direction of the sheet P on which it is placed.

[0028] In this embodiment of the image forming apparatus, if the length of the sheet P in the transport direction fits within the size of the main body of the image forming apparatus 100, a cassette-type (not shown) mounting section 102 is used. On the other hand, as in the embodiment, if the transport length of the sheet P does not fit within the size of the main body, the mounting section 102 is provided on the surface of the opened outer cover 108.

[0029] <Mechanism to prevent the inner cover from coming off> Next, with reference to Figures 4, 5, and 6, the mechanism for preventing the inner cover from coming off will be described. In recent years, there has been a demand for lighter image forming apparatuses 100. Therefore, the thickness of the cover members has been made as thin as possible, and the pivot points of the rotating shafts are configured to only engage with each other, without using any special fixing members. On the other hand, in the transportation of the apparatus body, the reduced weight of the apparatus may lead to rougher handling of the cargo during transport, raising concerns about increased impact forces on the apparatus due to collisions or drops.

[0030] In particular, the impact force on the device during transport affects each component within the image forming apparatus 100. During transport, as shown in Figure 2, the outer cover 108 is held in a closed position, and the dust cover 202 is also housed inside the device. In this state, when an impact is applied to the dust cover 202, the central part of the cover flexes due to its own weight, with the pivot points of the second pivot shafts 203 at both ends acting as fulcrums. If the direction of the impact is from the rotation axis of the dust cover 202 toward the cover's rotation end, or in the opposite direction, or in the direction of the rotation axis, the dust cover 202 has high rigidity and flexes little. However, if the direction of the impact is perpendicular to the cover surface of the dust cover 202, the dust cover 202 has low rigidity and flexes easily. When the flexing of the cover exceeds a certain amount, the second pivot shafts 203 detach from their pivot points, and the dust cover 202 falls out of the device.

[0031] Therefore, in this embodiment, when the outer cover 108 is closed, the restricting portion 200 provided on the outer cover 108 is placed at a predetermined position close to the axis of the second pivot shaft 203 of the dust cover 202, thereby suppressing the deflection of the dust cover 202. The predetermined position is not a position that restricts the position of the rear end of the standard paper when a sheet is placed on the cassette. In other words, it is not a position that restricts the rear end of the sheet when standard paper such as A4, A3, B4, or B5 is set on the cassette. That is, it is a position provided to prevent the dust cover 202 from coming off.

[0032] When the outer cover 108 is closed, both the outer cover 108 and the dust cover 202 are in an upright position. As described above, the restricting part 200 is engaged with the mounting part 102 and is movable in the sheet transport direction D. When the outer cover 108 is closed, the direction of movement of the restricting part 200 is the vertical direction of the device. Regardless of the position of the restricting part 200 within its movable range, a gap G is maintained between the dust cover 202 and the restricting part 200 so that the restricting part 200 does not interfere with the dust cover 202 when the outer cover 108 is closed.

[0033] Furthermore, the restricting portion 200 is located approximately in the center of the width of the sheet P. In this embodiment, the dust cover 202 and the restricting portion 200 are arranged in close proximity when the outer cover 108 is closed, and the position of the restricting portion 200 in the vertical direction of the device is approximately the same as the rotation axis of the dust cover 202. Specifically, it is desirable that the rotation centerline A of the dust cover 202 is located between the upstream first surface 200a and the downstream second surface 200b of the restricting portion 200. Also, as mentioned above, even if there are two or more configurations of the dust cover 202, the same effect can be obtained if the upright dust cover 202s are arranged at or below a predetermined distance apart. In other words, the dust cover comes into contact with the restricting portion 200 before the second rotation axis 203 of the dust cover 202 comes off the shaft support of the housing, thereby preventing the dust cover 202 from coming off.

[0034] As shown in Figure 6, within the movable range of the restricting part 200, an engaging part is provided to engage the positions of the restricting part 200 and the outer cover 108 in order to restrict the restricting part 200 to a predetermined position. Specifically, the engaging part is provided on the restricting part 200 with an elastically deformable elastic part 204 and a protruding part 205 that protrudes from the tip of the elastic part 204. In addition, the mounting part 102 is provided with a recessed part 206 which is an engaged part that engages with the shape of the protruding part 205 of the restricting part 200. When the restricting part 200 moves, the protruding part 205 engages with the recessed part 206 of the mounting part 102 at the predetermined position, so that the restricting part 200 is in a position to suppress the bending of the dust cover 202.

[0035] This configuration allows the restricting portion 200 to be restricted at a predetermined position, thereby suppressing the deflection of the dust cover 202. The elastic portion 204, protruding portion 205, and recessed portion 206 described above can be provided in either the restricting portion 200 or the mounting portion 102 to achieve the same effect.

[0036] [Embodiment 2] Next, Embodiment 2 of the present invention will be described. Embodiment 2 differs from Embodiment 1 in the shape of the dust cover 207, but otherwise is substantially the same as Embodiment 1. Figure 7 shows the dust cover 207 of Embodiment 2. Figure 7(a) is a cross-sectional view of the inner cover and the vicinity of the outer cover when the outer cover is in the closed position. Figure 7(b) is a perspective view of Figure 7(a).

[0037] As shown in Figure 7(b), if there is a notch 208 in the longitudinal direction of the centerline of the second rotation shaft 203 of the dust cover 207, the restricting portion 200 will not be effective if it is on the centerline of the second rotation shaft 203. In that case, a mechanism that can be stopped is provided on the outer cover so that it is held in a position facing the contour portion 209 located near the second rotation shaft 203. Specifically, it is desirable that the centerline B of the thickness of the rib of the contour portion 209 is located between the first upstream surface 200a and the second downstream surface 200b of the restricting portion 200.

[0038] This configuration makes it possible to achieve the same effects as in Embodiment 1. [Explanation of Symbols]

[0039] 100 Image forming apparatus 102 Mounting section 108 Outer cover (first cover) 109 First drive shaft section 200 Regulatory Department 202 Dust cover (second cover) 203 Second drive shaft section 204, 205, 206 Engaging parts 204 Elastic part 205 Protrusion 206 Recessed portion (engaged portion)

Claims

1. The casing and A first cover is supported on the housing so as to be openable and rotatable about a first pivot shaft, and has a mounting portion on which a sheet is placed. A regulating unit is provided movably with respect to the first cover and regulates the position of the sheet placed on the aforementioned mounting unit, The housing is supported so as to be openable and rotatable about a second pivot axis different from the first pivot axis, and the second cover covers the upper part of the sheet placed on the aforementioned mounting part when the first cover is open, The restricting portion has engaging portions that engage with each other at predetermined positions in order to restrict movement relative to the first cover. An image forming apparatus characterized in that, when the restricting portion is restricted by the engaging portion to the first cover at a predetermined position, and the second cover contacts the restricting portion before the second pivot shaft portion of the second cover disengages from the housing when the first cover is closed to the housing, the second cover contacts the restricting portion.

2. The image forming apparatus according to claim 1, characterized in that the restricting portion restricts the rear end of the sheet placed on the aforementioned mounting portion.

3. The first pivot shaft portion is provided at both ends of the first cover and is rotatably supported relative to the housing. The image forming apparatus according to claim 1 or 2, characterized in that the second pivot shaft portion is provided at both ends of the second cover and is rotatably supported with respect to the housing.

4. The engaging portion has an elastic portion in which a part of the restricting portion is elastically deformed, and a protruding portion that protrudes from the end of the elastic portion. The image forming apparatus according to any one of claims 1 to 3, characterized in that the mounting portion is provided with an engaging portion that engages with the protruding portion.

5. The regulating portion has a first surface provided on the upstream side in the sheet transport direction, and a second surface provided on the downstream side in the sheet transport direction that contacts the sheet placed on the aforementioned mounting portion. The image forming apparatus according to any one of claims 1 to 4, characterized in that, when the restricting portion is restricted by the engaging portion to the first cover at a predetermined position, and the first cover is in a closed position relative to the housing, the position of the center of the second pivot axis portion is located between the first surface and the second surface in the vertical direction.

6. The image forming apparatus according to any one of claims 1 to 5, characterized in that, when the first cover and the second cover are in a closed position relative to the housing, the distance of the gap provided between the second cover and the restricting portion is smaller than the amount of deflection of the second cover when the second pivot axis portion of the second cover, which is supported by the housing, detaches from the housing.

Images