Image forming apparatus

Abstract

To provide an image forming apparatus capable of suppressing deterioration of workability around a feeding unit by a simple structure.SOLUTION: An image forming apparatus includes: an apparatus body; a sheet conveyance path; a cover member; a conveyance unit; a sheet tray; a first sheet feeding part; and a feeding unit. The sheet conveyance path is formed inside the apparatus body. The cover member is rotatably supported around a lower end part with respect to the apparatus body and opens / closes the apparatus body. The conveyance unit is provided inside the cover member and is rotatably supported between an open position opening the sheet conveyance path and a close position. The first sheet feeding part has a feeding unit. The conveyance unit has a swing guide which is supported so that the lower end part can swing to the apparatus body, is arranged at a first position facing the feeding unit at the close position and configuring a part of the sheet conveyance path, and is arranged at a second position away from the feeding unit at the open position.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to an image forming apparatus such as a copying machine, a printer, a facsimile machine, and a multifunction machine thereof.

Background Art

[0002] Conventionally, an image forming apparatus including a device main body, a sheet tray on which sheets are stacked, and a feeding unit that feeds the sheets in the sheet tray to the downstream side is known (Patent Document 1). The sheet tray of Patent Document 1 is inserted and removed in the horizontal direction and is detachably provided on the device main body. The feeding unit is provided on the downstream side in the mounting direction of the sheet tray (the insertion direction with respect to the device main body). The feeding unit includes a pair of conveying rollers configured to include a feed roller and a retard roller, and feeds the sheets stacked on the sheet tray to the downstream side.

[0003] The retard roller is rotatably supported at the downstream end in the mounting direction of the sheet tray and moves along with the insertion and removal of the sheet tray. The retard roller faces the feed roller when the sheet tray is mounted on the device main body.

[0004] Such an image forming apparatus further includes a cover member that is supported on the side portion of the device main body so as to be openable and closable with respect to the device main body, and a conveying unit provided inside the cover member. The cover member constitutes the side surface of the device main body. The cover member is rotatably supported about a rotation fulcrum provided at the lower portion of the device main body, and is capable of operating in an open direction (a direction away from the device main body) and a closed direction (a direction approaching the device main body) with respect to the device main body. The conveying unit is supported so as to be rotatable about a rotation support shaft provided at the lower portion of the device main body, and is rotatably supported between an open position away from the device main body and a closed position approaching the device main body. The conveying unit is engageable with the cover member, and when the cover member is operated in the open direction with the cover member and the conveying unit engaged, the conveying unit moves to the open position.

[0005] Between the conveyance unit and the apparatus main body, there is a sheet conveyance path for conveying the sheet, which extends in the vertical direction (a direction perpendicular to the mounting direction). Along the sheet conveyance path, there are provided a secondary transfer roller for transferring the toner image onto the sheet and a fixing device for fixing the toner image transferred onto the sheet to the sheet. During the process of passing through the sheet conveyance path, it is possible to form an arbitrary image on the sheet. The above-described pair of conveyance rollers is also provided so as to face the sheet conveyance path, and the feed roller faces the wall surface on the side closer to the cover member among the wall surfaces constituting the sheet conveyance path.

[0006] Here, when performing the process of paper jam (hereinafter referred to as "jam process") occurring in the sheet conveyance path or when performing maintenance work on the fixing device, the secondary transfer roller, the feeding unit, etc., as described above, the conveyance unit is moved to the open position to expose a part of the sheet conveyance path to the outside of the apparatus main body (see FIG. 2 of Patent Document 1).

[0007] In addition, among the above-described image forming apparatuses, there are those in which an optional unit for accommodating sheets can be mounted at the lower part of the apparatus main body. The apparatus main body of such an image forming apparatus is provided with a carry-in port for carrying in the sheets discharged from the optional unit. The carry-in port opens on the lower surface of the apparatus main body and communicates with the sheet conveyance path.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0009] In an image forming apparatus capable of attaching an option unit to the lower part of the apparatus main body as described above, a sheet conveyance path extends to the lower part of the apparatus main body. Further, a sheet tray is inserted into the lower part inside the apparatus main body, and a feeding unit is also provided at a relatively lower position in the apparatus main body. Further, the rotation fulcrum of the cover member and the rotation support shaft of the conveyance unit are located in the lower part of the apparatus main body and are at a position relatively close to the feeding unit. For this reason, even when the cover member is opened together with the conveyance unit, the opposing interval between the feeding unit and a part of the wall surface of the sheet conveyance path is difficult to expand, and a working space around the feeding unit cannot be secured, resulting in deterioration of workability such as jam processing and maintenance work around the feeding unit.

[0010] Therefore, in view of the above problems, an object of the present invention is to provide an image forming apparatus capable of suppressing deterioration of workability around a feeding unit with a simple configuration.

Means for Solving the Problems

[0011] To achieve the above object, a first configuration of the present invention includes an apparatus main body, a sheet conveyance path, a cover member, a conveyance unit, a sheet tray, and a first sheet feeding unit. The apparatus main body has an image forming unit inside. The sheet conveyance path is formed inside the apparatus main body and extends vertically along the side surface of the apparatus main body. The cover member is rotatably supported with respect to the apparatus main body about the lower end portion and opens and closes the inside of the apparatus main body. The conveyance unit is provided inside the cover member and is rotatably supported between an open position for opening the sheet conveyance path and a closed position for closing it. The sheet tray is loaded with sheets. The first sheet feeding unit is provided at the lower part of the apparatus main body, and the sheet tray is detachably attached thereto. The first sheet feeding unit has a feeding unit for feeding the sheets stacked on the sheet tray. The conveyance unit has a swing guide. The swing guide is swingably supported by the apparatus main body at the lower end portion, is disposed at a first position facing the feeding unit and constituting a part of the sheet conveyance path in the closed position, and is disposed at a second position separated from the feeding unit in the open position.

Effects of the Invention

[0012] According to the first configuration of the present invention, when the cover member is opened together with the conveyance unit, the swing guide moves to a second position separated from the feeding unit, so that the facing interval between the feeding unit and the swing guide expands, securing a working space around the feeding unit and suppressing deterioration of workability. Further, the swinging operation of the swing guide accompanying the operation of the cover member is not due to a complicated configuration such as a link mechanism, but is due to a simple configuration by its own weight.

[0013] Therefore, it is possible to provide an image forming apparatus capable of suppressing deterioration of workability around the feeding unit with a simple configuration.

Brief Description of the Drawings

[0014]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Embodiments for Carrying Out the Invention

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a cross-sectional view showing the schematic configuration of the image forming apparatus 100 of the present invention. An option unit 101 is connected below the image forming apparatus 100 to constitute an image forming unit 105. In the present embodiment, the image forming apparatus 100 is a four-color tandem type color copying machine that performs image formation by arranging four photosensitive drums 1a, 1b, 1c, and 1d corresponding to four different colors (magenta, cyan, yellow, and black) in parallel.

[0016] Inside the apparatus main body 40 of the image forming apparatus 100, four image forming units Pa, Pb, Pc, and Pd are arranged in order from the left side in FIG. 1. These image forming units Pa to Pd are provided corresponding to images of four different colors (magenta, cyan, yellow, and black), and form magenta, cyan, yellow, and black images sequentially through the steps of charging, exposure, development, and transfer respectively.

[0017] The above-described photosensitive drums 1a to 1d that carry visible images (toner images) of each color are respectively arranged in these image forming units Pa to Pd. Further, an intermediate transfer belt 8 that rotates in the counterclockwise direction in FIG. 1 is provided adjacent to each of the image forming units Pa to Pd. After the toner images formed on these photosensitive drums 1a to 1d are sequentially transferred onto the intermediate transfer belt 8 that moves while contacting each of the photosensitive drums 1a to 1d, they are transferred onto the papers P1 and P2 (sheets) at once by the secondary transfer roller 9, and further, after being fixed on the papers P1 and P2 by the fixing device 15, they are discharged from the image forming apparatus 100. While rotating the photosensitive drums 1a to 1d in the clockwise direction in FIG. 1, an image forming process for each of the photosensitive drums 1a to 1d is executed.

[0018] A first sheet feeding unit 60 is provided at the lower part of the apparatus main body 40. A second sheet feeding unit 61 is provided below the first sheet feeding unit 60. The first sheet feeding unit 60 is formed inside the apparatus main body 40. The second sheet feeding unit 61 is formed inside an option unit 101 described later. Inside the first sheet feeding unit 60, a paper cassette 16 (sheet tray) for accommodating the paper P1 is stored. The first sheet feeding unit 60 has an opening formed in one side surface in the horizontal direction of the apparatus main body 40 (here, the left side surface shown in FIG. 1) (not shown). The paper cassette 16 can be inserted into and removed from the apparatus main body 40 in the horizontal direction, that is, it can be mounted and removed, through this opening. Hereinafter, the horizontal direction in which the paper cassette 16 is inserted and removed is referred to as the mounting direction.

[0019] The image forming apparatus 100 has a paper inlet 44 that opens on the bottom surface (the surface located at the lowermost part of the apparatus main body 40 and facing downward). A paper conveyance path 14 (sheet conveyance path) is connected to the paper inlet 44 so as to extend upward from the opening edge of the paper inlet 44. At an intermediate position of the paper conveyance path 14, a registration roller pair 13, the above-described secondary transfer roller 9, and a fixing device 15 are provided in order from the bottom. Further, the paper conveyance path 14 branches into two at a branch portion 17 (sheet inversion portion) located on the downstream side of the fixing device 15. One of the branched paper conveyance paths 14 communicates with the outside of the apparatus main body 40 via a discharge roller pair 18. The other of the branched paper conveyance paths 14 is connected to a reverse conveyance path 21 (back surface conveyance path). The reverse conveyance path 21 extends downward from the branch portion 17 and merges with the paper conveyance path 14 at a position upstream of the secondary transfer roller 9.

[0020] An option unit 101 capable of accommodating paper P2 therein is attached to the lower part of the image forming apparatus 100. The option unit 101 includes the second sheet feeding unit 61 described above. The second sheet feeding unit 61 has an opening formed in one side surface in the horizontal direction of the option unit 101 (here, the left side surface shown in FIG. 1) (not shown). Similar to the first sheet feeding unit 60, a paper cassette 16 (sheet tray) for accommodating paper P1 is housed inside the second sheet feeding unit 61. The paper cassette 16 is detachable from the option unit 101 in the mounting direction from an opening (not shown).

[0021] The option unit 101 has a discharge port 46 for discharging the paper P2 housed therein. In a state where the option unit 101 is attached to the image forming apparatus 100, the paper inlet 44 of the paper conveyance path 14 is adjacent to the discharge port 46 in the paper conveyance direction (here, the vertical direction). The paper inlet 44 receives the paper discharged from the discharge port 46.

[0022] On the downstream side in the mounting direction of the first sheet feeding unit 60 (the front side in the direction in which the paper cassette 16 is inserted into the apparatus main body 40), an upper feed guide 62 that forms a part of the wall surface of the paper conveyance path 14 is formed. The upper feed guide 62 extends from the internal space of the first sheet feeding unit 60 toward the downstream side in the paper conveyance direction. A feed unit 41 is provided on the upper feed guide 62. The paper cassette 16 mounted in the first sheet feeding unit 60 is connected to the paper conveyance path 14 via the feed unit 41. The feed unit 41 feeds the sheets P1 accommodated in the paper cassette 16 one by one to the paper conveyance path 14.

[0023] The feed unit 41 has a pickup roller 43 and a pair of conveyance rollers 42. The pickup roller 43 is provided so as to face the sheet P1 in the paper cassette 16 in the vertical direction and is in contact with the upper surface of the stack of sheets P1 in the paper cassette 16. By rotating in the counterclockwise direction shown in FIG. 1, the pickup roller 43 conveys the uppermost sheet P1 of the stack of sheets P1 to the downstream side.

[0024] The pair of conveyance rollers 42 is provided on the downstream side of the pickup roller 43. The pair of conveyance rollers 42 is a pair of rotating rollers composed of a feed roller 42a (feeding roller) and a retard roller 42b. The pair of conveyance rollers 42 feeds the sheet P1 conveyed by the pickup roller 43 one by one to the paper conveyance path 14. As a result, even when a plurality of sheets P1 are fed simultaneously by the pickup roller 43, the sheets P1 can be handled by the pair of conveyance rollers 42, so that only the uppermost one sheet in the paper cassette 16 can be conveyed.

[0025] FIG. 2 is a perspective view showing the upper feed guide 62. FIG. 3 is a cross-sectional view around the paper conveyance path 14 and the reverse conveyance path 21 in the image forming apparatus 100 of FIG. 1. A feed holder 63 is attached to and supported by the upper feed guide 62. The feed holder 63 has a pair of side wall portions 69 facing each other in the sheet width direction (the depth direction of the paper surface in FIGS. 1 and 3). The central axes of the feed roller 42a and the pickup roller 43 are supported so as to span between the pair of side wall portions 69. That is, the feed roller 42a and the pickup roller 43 are rotatably supported by the feed holder 63. The feed holder 63 is detachable from the upper feed guide 62 from the side of the paper conveyance path 14 (the side of the cover member 33 to be described later) (see FIG. 1).

[0026] With the paper cassette 16 attached to the first sheet feeding unit 60 and the feed holder 63 attached to the upper conveyance guide, the feed roller 42a faces the retard roller 42b and constitutes the conveyance roller pair 42.

[0027] A lower feed guide 64 is provided at the end of the first sheet feeding unit 60 on the side of the paper conveyance path 14 in the mounting direction (the innermost part in the mounting direction). The lower feed guide 64 faces the upper feed guide 62 in the vertical direction and extends from the internal space of the first sheet feeding unit 60 toward the downstream side in the paper conveyance direction.

[0028] As shown in FIGS. 1 and 3, a facing wall 67 rising upward from the bottom of the paper cassette 16 is formed at the end of the lower feed guide 64 on the side of the paper conveyance path 14 in the mounting direction. The facing wall 67 faces the swing guide 45 to be described later in the mounting direction with the paper conveyance path 14 interposed therebetween.

[0029] On the downstream side of the conveying roller pair 42, a registration roller pair 13 is provided. The sheet P1 fed into the sheet conveying path 14 by the feeding unit 41 is conveyed to the secondary transfer roller 9 after the skew is corrected and the timing with image formation is adjusted by the registration roller pair 13. Also, the sheet P2 carried in from the carry-in port 44 is also conveyed to the secondary transfer roller 9 by the registration roller pair 13. Since the modes of image formation on the sheet P1 and the sheet P2 conveyed by the registration roller pair 13 are both common, hereinafter, only the mode of image formation on the sheet P1 will be described, and the description of the sheet P2 will be omitted.

[0030] A sheet made of a dielectric resin is used for the intermediate transfer belt 8, and a mainly seamless belt is used. The intermediate transfer belt 8 and the secondary transfer roller 9 are rotationally driven at the same linear speed as the photosensitive drums 1a to 1d by a belt drive motor (not shown). Also, on the downstream side of the secondary transfer roller 9, a blade-shaped belt cleaner 19 for removing toner and the like remaining on the surface of the intermediate transfer belt 8 is disposed.

[0031] Next, returning to FIG. 1, the image forming units Pa to Pd will be described. Around and below the rotatably arranged photosensitive drums 1a to 1d, charging devices 2a, 2b, 2c, and 2d for charging the photosensitive drums 1a to 1d, an exposure unit 5 for performing exposure based on image data on each of the photosensitive drums 1a to 1d, developing devices 3a, 3b, 3c, and 3d for developing the electrostatic latent images formed on the photosensitive drums 1a to 1d with toner, and cleaning devices 7a, 7b, 7c, and 7d for collecting and removing the developer (toner) remaining after the transfer of the toner image on the photosensitive drums 1a to 1d are provided.

[0032] The image reading unit 23 is composed of a scanning optical system equipped with a scanner lamp that illuminates the document during copying and a mirror that changes the optical path of the reflected light from the document, a condenser lens that condenses the reflected light from the document to form an image, a CCD sensor that converts the formed image light into an electrical signal, etc. (none of which are shown in the figure), and reads the document image and converts it into image data.

[0033] When performing the copy operation, the image reading unit 23 reads the image data of the document and converts it into an image signal. On the other hand, the surfaces of the photosensitive drums 1a to 1d are uniformly charged by the charging devices 2a to 2d, and then light is irradiated based on the image data by the exposure unit 5 to form an electrostatic latent image corresponding to the image data on each of the photosensitive drums 1a to 1d. The developing devices 3a to 3d are provided with developing rollers (developer carriers) arranged opposite to the photosensitive drums 1a to 1d, and each is filled with a two-component developer containing toners of magenta, cyan, yellow, and black colors in a predetermined amount.

[0034] When the ratio of the toner in the two-component developer filled in each of the developing devices 3a to 3d falls below the specified value due to the formation of the toner image described later, the developer is replenished from the containers 4a to 4d to each of the developing devices 3a to 3d. The toner in this developer is supplied onto the photosensitive drums 1a to 1d by the developing devices 3a to 3d and electrostatically adheres to form a toner image corresponding to the electrostatic latent image formed by the exposure of the exposure unit 5.

[0035] Then, by applying a predetermined transfer voltage between the primary transfer rollers 6a to 6d and the photoreceptor drums 1a to 1d by the primary transfer rollers 6a to 6d, the magenta, cyan, yellow, and black toner images on the photoreceptor drums 1a to 1d are primarily transferred onto the intermediate transfer belt 8. These four-color images are formed with a predetermined positional relationship determined in advance for a predetermined full-color image formation. The primary transfer rollers 6a to 6d are rotationally driven at the same linear speed as the photoreceptor drums 1a to 1d and the intermediate transfer belt 8 by a primary transfer drive motor (not shown). Thereafter, in preparation for the subsequent formation of a new electrostatic latent image, the toner remaining on the surfaces of the photoreceptor drums 1a to 1d is removed by the cleaning devices 7a to 7d.

[0036] The intermediate transfer belt 8 is stretched over the driven roller 10 and the driving roller 11. When the intermediate transfer belt 8 starts to rotate counterclockwise as the driving roller 11 rotates by the belt driving motor, the sheet P1 is conveyed from the registration roller pair 13 to the nip portion (secondary transfer nip portion) of the secondary transfer roller 9 provided adjacent to the intermediate transfer belt 8 at a predetermined timing, and the toner image of the full-color image is secondarily transferred onto the sheet P1 at the nip portion. The sheet P1 onto which the toner image has been transferred is conveyed to the fixing device 15 via the sheet conveyance path 14.

[0037] The sheet P1 conveyed to the fixing device 15 is heated and pressurized when passing through the nip portion (fixing nip portion) of the fixing roller pair 15a. At this time, the toner image is fixed on the surface of the sheet P1, and a predetermined full-color image is formed. The sheet P1 on which the full-color image has been formed has its conveyance direction sorted by the branching portion 17 branched in a plurality of directions. When an image is formed only on one side of the sheet P1, it is discharged onto the discharge tray 20 provided on the upper surface of the apparatus main body 40 by the discharge roller pair 18 as it is.

[0038] On one hand, when forming images on both sides of the paper P1, the paper P1 passes through the fixing device 15, and a part of the paper P1 with a full-color image formed on the surface is once protruded from the discharge roller pair 18 to the outside of the apparatus main body 40. Then, the discharge roller pair 18 is rotated reversely to feed this paper P1 into the branch portion 17 and divert it to the reverse conveyance path 21 by the branch portion 17. The paper P1 that has passed through the reverse conveyance path 21 and reached the confluence portion with the paper conveyance path 14 is re-conveyed to the secondary transfer roller 9 with the image surface being reversed. Then, the next image formed on the intermediate transfer belt 8 is transferred by the secondary transfer roller 9 to the back surface (the surface where no image is formed) of the paper P1. Then, after the paper P1 is conveyed to the fixing device 15 and the toner image is fixed, it is discharged to the discharge tray 20 by the discharge roller pair 18.

[0039] FIG. 4 is a cross-sectional view of the image forming apparatus 100 with the cover member 33 opened. FIG. 5 is a cross-sectional view of the image forming apparatus 100 with the cover member 33 opened together with the conveyance unit 35 and the conveyance unit 35 being in the open position S2. Note that FIG. 5 shows a state where the paper cassette 16 is removed from the apparatus main body 40.

[0040] As shown in FIGS. 3 to 5, a cover member 33 is provided on the side portion of the apparatus main body 40. The cover member 33 constitutes the side surface of the image forming apparatus 100 and is rotatably supported at a fulcrum 33a located at the lower part of the apparatus main body 40. A conveyance unit 35 is disposed inside the cover member 33. The conveyance unit 35 is rotatably supported between the closed position S1 (see FIGS. 3 and 4) with respect to the apparatus main body 40 and the open position S2 (see FIG. 5) about a support shaft 35a located at the lower part of the apparatus main body 40.

[0041] An engagement mechanism (not shown) is provided between the conveyance unit 35 and the cover member 33. With the conveyance unit 35 and the cover member 33 engaged by this engagement mechanism, it is possible to rotate the cover member 33 together with the conveyance unit 35. At this time, the cover member 33 rotates about the fulcrum 33a, and the conveyance unit 35 rotates about the support shaft 35a, respectively.

[0042] As shown in FIG. 3, when the conveyance unit 35 is in the closed position S1, a part of the conveyance surface of the paper conveyance path 14 is formed between the conveyance unit 35 and the apparatus main body 40. Further, when the conveyance unit 35 is in the closed position S1 and the cover member 33 is closed, a reverse conveyance path 21 is formed between the conveyance unit 35 and the cover member 33. The reverse conveyance path 21 extends downward along the side surface of the image forming apparatus 100 from the branch portion 17, curves in a substantially C shape, and merges with the paper conveyance path 14 at a position upstream of the secondary transfer roller 9 and the registration roller pair 13. The inner surface of the cover member 33 forms a part of one conveyance surface of the reverse conveyance path 21, and the outer surface of the conveyance unit 35 forms the other conveyance surface of the reverse conveyance path 21.

[0043] With the conveyance unit 35 arranged in the closed position S1, by rotating only the cover member 33 about the fulcrum 33a in the opening direction with respect to the apparatus main body 40 (the direction away from the apparatus main body 40), the reverse conveyance path 21 is widely exposed (see FIG. 4). Further, by rotating the cover member 33 together with the conveyance unit 35 in the opening direction, the conveyance unit 35 moves away from the apparatus main body 40 to the open position S2, and the paper conveyance path 14 is widely exposed (see FIG. 5). As a result, access to the feeding unit 41 is possible from the cover member 33 side.

[0044] A swing guide 45 is provided at the lower part of the conveyance unit 35 (see FIG. 3). The swing guide 45 is provided so as to be adjacent to the paper inlet 44 in the paper conveyance direction (here, the vertical direction), and constitutes a part of the wall surface of the paper conveyance path 14. The swing guide 45 is supported so as to be rotatable about the fulcrum 47. The swing guide 45 is arranged at the first position S3 facing the feeding unit 41 in the mounting direction when the cover member 33 is closed. The swing guide 45 constitutes a part of the inner wall of the paper conveyance path 14, and guides the paper P2 carried in from the paper inlet 44 to the downstream side of the paper conveyance path 14.

[0045] A bypass path 66 is formed at a position between the swing guide 45 and the opposing wall 67 in the paper conveyance path 14. The bypass path 66 extends upward from the paper inlet 44. The paper P2 carried in from the paper inlet 44 is guided through this bypass path 66 to the paper conveyance path 14.

[0046] The swing guide 45 is provided with a weight portion 48 at a position below the fulcrum 47 so that the center of gravity is biased downward. Due to this weight portion 48, as the swing guide 45 rotates around the support shaft 35a of the conveyance unit 35, the swing guide 45 swings around the fulcrum 47 by its own weight. That is, since the center of gravity of the swing guide 45 is biased downward by the weight portion 48, when the cover member 33 is operated in the opening direction together with the conveyance unit 35, the swing guide 45 rotates downward in the counterclockwise direction shown in the figure around the fulcrum 47 and moves to the second position S4 which is at a position separated from the feeding unit 41. On the contrary, when the open cover member 33 is operated in the closing direction (the direction approaching the apparatus main body 40) together with the conveyance unit 35 located at the open position S2, the swing guide 45 rotates by its own weight around the fulcrum 47 and moves from the second position S4 toward the first position S3 so as to approach the feeding unit 41.

[0047] The broken line portion in Fig. 5 shows the virtual position of the swing guide 45 assuming that the swing guide 45 did not rotate when the cover member 33 was opened together with the conveyance unit 35. As shown in the figure, as the swing guide 45 rotates and moves from the position of the broken line portion to the position of the solid line portion (the second position S4), the interval between the feed roller 42a of the feeding unit 41 and the swing guide 45 has widened. That is, compared with the interval between the feeding unit 41 and the swing guide 45 when the swing guide 45 did not rotate, the interval between the swing guide 45 at the second position S4 and the feeding unit 41 has become wider. As a result, the width of the bypass path 66 has also widened (not shown in the figure).

[0048] An urging member 49 is provided between the cover member 33 and the swing guide 45. The urging member 49 can adopt a configuration including a helically formed coil spring 50 and a contact portion 51 provided at the tip of the coil spring 50. The contact portion 51 can be a member made of a general resin material such as silicon resin or PP resin.

[0049] When the cover member 33 is operated in the closing direction together with the transport unit 35 and the cover member 33 is closed with respect to the apparatus main body 40, the weight portion 48 of the swing guide 45 and the contact portion 51 come into contact with each other. For this reason, the swing guide 45 is urged toward the feed unit 41 by the elastic force of the coil spring 50 and is positioned at the first position S3 facing the feed unit 41. When the cover member 33 is operated in the opening direction together with the transport unit 35 and the transport unit 35 is at the open position S2, the contact portion 51 is separated from the swing guide 45 (see FIG. 5). For this reason, the swing guide 45 rotates to the second position S3 by its own weight without being urged by the urging member 49.

[0050] As described above, when the cover member 33 is closed and the swing guide 45 at the first position S3 is opened together with the cover member 33 and the transport unit 35, it moves to the second position S4 by its own weight. Since the second position S4 is a position separated from the feed unit 41, the distance between the feed unit 41 and the swing guide 45 increases, and the workability around the feed unit 41 such as the replacement operation of the feed roller 42a is improved. Further, the swinging operation of the swing guide 45 accompanying the operation of the cover member 33 does not require a complicated configuration such as a link mechanism and is due to a simple configuration by its own weight. Therefore, it is possible to provide an image forming apparatus capable of suppressing the deterioration of the workability around the feed unit 41 with a simple configuration.

[0051] Also, as described above, when the cover member 33 is closed, the contact portion 51 of the biasing member 49 contacts the weight portion 48 of the swing guide 45, and the biasing member 49 biases the swing guide 45 toward the first position S3. Therefore, when the cover member 33 is closed, the swing guide 45 is pressed against a positioning portion (not shown) in the apparatus main body 40 and appropriately moves to the first position S3. Further, when the cover member 33 is opened together with the conveyance unit 35, the biasing member 49 separates from the swing guide 45 and stops biasing the swing guide 45, and the swing guide 45 rotates by its own weight. Therefore, by adopting the configuration including the biasing member 49 described above, when the cover member 33 is opened, the swing guide 45 rotates to the second position S4 by its own weight, and when the cover member 33 is closed, the swing guide 45 is positioned at the position of the first position S3, and with a simple configuration, more appropriate positioning of the rotation of the swing guide 45 can be achieved.

[0052] In addition, the present invention is not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the above-described embodiment, the swing guide 45 and the carry-in port 44 are configured by separate members, and the swing guide 45 is arranged adjacent to the carry-in port 44. However, the swing guide 45 can be configured to form a part of the carry-in port 44. In this case, the lower end portion of the swing guide 45 is located at the lowermost portion of the apparatus main body 40 and forms a part of the opening edge of the carry-in port 44. By doing so, as the cover member 33 rotates, the portion of the paper conveyance path 14 facing the feeding unit 41 is separated from the feeding unit 41 over a relatively wide range. Therefore, the working space around the feeding unit 41 becomes wider, and it is possible to suitably suppress the deterioration of workability.

[0053] Further, as the configuration of the biasing member 49, the one including the coil spring 50 and the contact portion 51 has been described. However, a configuration may be adopted in which the contact portion 51 is not provided and the coil spring 50 directly contacts the swing guide 45. By doing so, the structure of the biasing member 49 becomes simple, and an increase in manufacturing cost can be suppressed.

Industrial Applicability

[0054] The present invention can be used in image forming apparatuses such as copiers, printers, facsimiles, and their multifunction machines. By using the present invention, when the cover member is opened, the distance between the feeding unit and the swing guide is expanded, and a working space around the feeding unit can be secured. Therefore, it is possible to provide an image forming apparatus capable of suppressing the deterioration of workability around the feeding unit with a simple configuration.

Explanation of Signs

[0055] 14 Paper conveyance path (sheet conveyance path) 16 Paper cassette (sheet tray) 17 Branch portion (sheet inversion portion) 21 Inversion conveyance path (back surface conveyance path) 33 Cover member 35 Conveyance unit 40 Apparatus main body 41 Feeding unit 42 Pair of conveyance rollers 42a Feed roller (feeding roller) 44 Loading port 45 Swing guide 49 Biasing member 60 First sheet feeding portion 61 Second sheet feeding portion 62 Upper feeding guide 63 Feeding holder 64 Lower feeding guide 66 Bypass path 67 Opposing wall 100 Image forming apparatus P1, P2 Paper (sheet) Pa~Pd Image forming portion S1 Closed position S2 Open position S3 First position S4 Second position

Claims

1. An apparatus main body having an image forming unit therein; A sheet conveyance path formed inside the apparatus main body and extending vertically along a side surface of the apparatus main body; A cover member rotatably supported about a lower end portion with respect to the apparatus main body and opening and closing the inside of the apparatus main body; A conveyance unit provided inside the cover member and rotatably supported between an open position for opening the sheet conveyance path and a closed position for closing the sheet conveyance path; A sheet tray on which sheets are stacked; A first sheet feeding unit provided at a lower portion of the apparatus main body and to which the sheet tray is detachably attached; A biasing member provided on the cover member; Comprising: The first sheet feeding unit has a feeding unit for feeding the sheet stacked on the sheet tray; The conveyance unit has a lower end portion swingably supported by the apparatus main body; The conveyance unit has a swing guide that supports an upper end portion thereof so that a lower end portion thereof swings with respect to the conveyance unit; The swing guide is in a first position that faces the feeding unit and forms a part of the sheet conveyance path when the conveyance unit is in the closed position, and is in a second position spaced apart from the feeding unit when the conveyance unit is in the open position; The biasing member abuts against the swing guide and biases the swing guide toward the first position when the conveyance unit is in the closed position, and is separated from the swing guide when the conveyance unit is in the open position. An image forming apparatus characterized by this.

2. A sheet reversing unit connected to a downstream side of the image forming unit and reversing a conveyance direction of the sheet on which an image is formed by the image forming unit; The image forming apparatus according to claim 1, further comprising: a back conveyance path formed between the conveyance unit and the cover member and receiving the sheet reversed by the sheet reversing unit and re-feeding the sheet to the sheet conveyance path.

3. The feeding unit has a pickup roller that abuts against an upper surface of the sheet stacked on the sheet tray and feeds the sheet, a feeding roller that feeds the sheet fed from the pickup roller downstream, and a feeding holder that supports the pickup roller and the feeding roller and is detachable from the apparatus main body from the cover member side. The image forming apparatus according to claim 1 or 2, characterized in that the feeding holder is accessible from the cover member side in a state where the swing guide is disposed at the second position.

4. comprising a second sheet feeding unit stacked below the first sheet feeding unit, wherein the first sheet feeding unit has an upper feeding guide on which the feeding holder is supported, and a lower feeding guide positioned below the upper feeding guide; wherein the lower feeding guide has an opposing wall that opposes the swing guide at a lower end portion of the conveying unit; The image forming apparatus according to claim 3, wherein the swing guide forms a bypass path for guiding the sheet fed from the second sheet feeding unit to the sheet conveyance path between the opposing wall at the closed position.

Images