Sheet feeding device and image forming device

Abstract

To provide a sheet feeding device in which a rotation shaft of an opening / closing member is disposed as close as possible to a device body side while avoiding interference with a holding part of a swing shaft of a receiving stand of a separation member.SOLUTION: A sheet feeding device has: an opening / closing member 67 that can be opened and closed around a rotation shaft 67d relative to a device body 2 and has a loading part on which sheets are loaded in an open state; feeding means that has a sheet feeding member (roller 72) contacting upper surfaces of the sheets loaded in the loading part to feed the sheets, a feeding member (roller 71) contacting upper surfaces of the sheets fed from the sheet feeding member to feed the sheets, and a separation member (bottom plate pad 68) arranged facing the feeding member and separating the sheets one by one; a guide member 74 that guides the sheets fed from feeding means; and a receiving stand 75 that holds a separation member (pad 76) and is swingably supported by the guide member 74, wherein swing shafts 75a and 75b of the receiving stand 75 overlap with the opening / closing member 67 in the open state when viewed from an axial direction.SELECTED DRAWING: Figure 5B

Description

[Technical Field]

[0001] The present invention relates to a sheet feeding device, and an image forming apparatus including the sheet feeding device, such as a copying machine, a facsimile machine, a printer, a printing machine, an inkjet recording apparatus, or a multifunction machine that combines at least two of them. [Background technology]

[0002] Image forming apparatuses such as copiers including PPCs (plain paper copiers), facsimiles, printers, printing presses, inkjet recording apparatuses, etc. generally need to conserve energy and have as small a machine size as possible. For this reason, there has been a trend toward miniaturization of conveying means for conveying and supplying image-forming media or sheet-like recording media (hereinafter also referred to as "sheets"), on which images are formed, from sheet storage means or sheet stacking means for stacking sheets to the image forming apparatus main body.

[0003] The sheet feeding device described in Patent Document 1 has an opening / closing member (manual paper feed tray) on the side of the main body of the image forming apparatus. This opening / closing member is normally stored vertically on the side of the main body so as not to get in the way, but when manual paper feed is performed, it opens outward so that paper can be loaded on the stacking section above the opening / closing member. DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0004] When the opening / closing member is in the vertically stored state, it protrudes outward from the side of the main body by the thickness of the opening / closing member. To reduce this protrusion, it is necessary to position the pivot axis of the opening / closing member as close to the main body as possible.

[0005] However, in addition to the bearing portion that supports the rotation shaft of the opening / closing member, the main body also contains a guide member that guides the paper fed from the opening / closing member, a holder for the swing shaft of the receiving base of the separation member (friction pad), etc. The bearing portion for the swing shaft and the holder for the swing shaft are supported by overhanging guide members.

[0006] Therefore, if the pivot shaft and its bearing of the opening / closing member are to be positioned closer to the main body, the opening / closing member will interfere with the guide member and the holder, making it difficult to position the pivot shaft and its bearing closer to the main body.

[0007] The present invention has been made in consideration of the above circumstances, and its purpose is to position the rotation axis of the opening / closing member as close as possible to the device main body while avoiding interference with the holding portion of the swing axis of the receiving base of the separating member. [Means for solving the problem]

[0008] To achieve the above-mentioned object, the sheet feeding device of the present invention comprises an opening / closing member that can be opened and closed relative to the device main body around a pivot axis and has a stacking section on which sheets are stacked when open, a sheet feeding member that abuts against the upper surface of the sheets stacked on the stacking section to feed the sheets, a feeding member that abuts against the upper surface of the sheets fed from the sheet feeding member to feed the sheets, a separating member that is arranged opposite the feeding member and separates the sheets one by one, a guide member that guides the sheets fed from the feeding means, and a receiving table that holds the separating member and is swingably supported by the guide member, and is characterized in that the swing axis of the receiving table overlaps with the opening / closing member when open when viewed from its axial direction. [Effects of the Invention]

[0009] According to the present invention, the pivot shaft of the opening / closing member can be positioned as close as possible to the device main body while avoiding interference with the holding portion of the pivot shaft of the receiving base of the separating member. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating the configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 2A] FIG. 2 is a perspective view of the opening / closing member in an open state. [Figure 2B] FIG. 2 is a plan view of the opening / closing member in an open state. [Figure 2C] FIG. 2B is an enlarged view of a main part of FIG. 2A. [Figure 2D] 2D is a diagram in which the opening / closing member is omitted from FIG. 2C. [Figure 3A] FIG. 10 is a side view of the opening / closing member during manual paper feeding. [Figure 3B] FIG. 10 is a side view of the opening / closing member when manual paper feeding is stopped. [Figure 3C] FIG. 3B is an enlarged view of a main part of FIG. 3A. [Figure 3D] 10 is a diagram showing the positional relationship between a nip tangent of a feed roller and a swing axis of a receiving table. FIG. [Figure 4A] 2D is a diagram in which the feed shaft, feed roller, pickup roller, and idler gear are omitted from FIG. 2C. [Figure 4B] FIG. 4B is a plan view of FIG. 4A. [Figure 4C] FIG. [Figure 5A] FIG. 10 is a side view of the opening / closing member in a vertically stored state. [Figure 5B] FIG. 5B is an enlarged view of a main part of FIG. 5A. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, an embodiment of the present invention (hereinafter referred to as "embodiment") will be described with reference to the drawings. Components such as members and components having the same function and shape will be given the same reference numerals, and once they have been described, their description will be omitted as appropriate.

[0012] Overall configuration of the copier The overall configuration of a copier 1 as an example of an image forming apparatus will be described with reference to Figure 1. In the following description, "image forming apparatus" refers to an apparatus that forms an image by applying developer or ink to a medium such as paper or an OHP sheet. "Image formation" refers not only to applying meaningful images such as characters or figures to a medium, but also to applying meaningless images such as patterns to a medium. "Sheets" include cardboard, postcards, envelopes, plain paper, thin paper, coated paper (such as coated paper and art paper), tracing paper, OHP sheets, OHP film, fiber, fabric, leather, metal, plastic, glass, wood, ceramics, etc.

[0013] Copier 1 is a monochrome copier that reads an image from the surface of an original and forms a copy image on various sheet-like recording media (hereinafter referred to as "sheets") such as recording paper, transfer paper, paper, transparency film, etc. The dimensions, materials, shapes, relative positions, etc. in the description of each component are examples only, and unless otherwise specified, are not intended to limit the scope of this invention to them.

[0014] The copier 1 has an image forming device main body 2 having an image forming section as an image forming means for performing a predetermined image formation process based on a read original image, a paper feeding device 3 on which the image forming device main body 2 is placed and which supplies sheets S one by one to the device main body 2, and an original reading device 4 attached to the image forming device main body 2 for reading the original image and sending this original image information to the image forming device main body 2.

[0015] An output tray 9 for discharging and stacking sheets that have passed through the image forming apparatus main body 2 is provided at the top of the image forming apparatus main body 2 so as to form a space below the document reading device 4. A sheet transport path R1 (hereinafter also referred to as "transport path R1") for moving sheets S is formed from the paper feed device 3 to the output tray 9. Most of this transport path R1 extends from the paper feed device 3 to the top of the image forming apparatus main body 2, in an approximately vertically upward direction relative to an approximately horizontal line, i.e., in an approximately vertically upward direction, and several sheet transport means composed of pairs of transport rollers or roller pairs are provided on the transport path R1 at predetermined intervals according to the minimum size of sheets S.

[0016] One of these sheet transport means is configured to always continue transporting the sheet S on the transport path R1 by clamping it, etc. Furthermore, the sheet feeding device 3 is provided with a sheet transport device 5 that feeds and transports the sheets S stored in each stage of the sheet feeding device 3 to a pair of registration rollers 21 on the transport path R1. Note that the sheet feeding device 8 that feeds sheets from the manual paper feed unit will be described later with reference to FIGS. 2A and 2B.

[0017] Inside the image forming apparatus main body 2, a photosensitive unit 10 and a fixing device 11 are arranged in this order from the upstream side to the downstream side of the transport path R1 as an image forming section that forms an image. After the photosensitive unit 10 transfers the toner image that it has generated onto the sheet S that is transported from the upstream side to the downstream side on this transport path R1, the fixing device 11 fixes the transferred toner image onto the sheet S, and the sheet S with the fixed toner image is discharged to a paper output tray 9 that is arranged at the end of the transport path R1.

[0018] The photoreceptor unit 10 has a single drum-shaped photoreceptor 10A as an image carrier, and is rotatably supported on a side plate (not shown) inside the image forming apparatus main body 2 around a substantially horizontally disposed rotation axis. The photoreceptor 10A has a well-known cylindrical shape with a predetermined diameter. A rotational driving force is transmitted to the photoreceptor 10A from a driving source such as a motor provided on either the photoreceptor unit 10 side or the image forming apparatus main body 2 side, and the photoreceptor 10A is driven to rotate at a stable, constant speed in the direction indicated by the arrow in the figure.

[0019] Around photoreceptor 10A, in the rotation direction indicated by the arrow in the figure, are arranged developing device 12, transfer device 13, photoreceptor cleaning device 18, static eliminator, and charging device 14. Within the range of one rotation of photoreceptor 10A in the counterclockwise rotation direction, each of these devices 12 to 14 sets a developing position, a transfer position, a cleaning position, a static eliminator position, and a charging position, in that order from upstream to downstream.

[0020] Furthermore, a latent image forming position is set between the charging position and the developing position, and an exposure device 47 for irradiating this latent image forming position with a predetermined laser beam to write an invisible latent image according to image information is disposed diagonally below and slightly spaced from the photosensitive unit 10. Then, the photosensitive member 10A is rotated counterclockwise as predetermined, and the devices 12 to 14 and the exposure device 47 perform predetermined linked cooperative operations in synchronization with the rotation of the photosensitive member 10A, thereby executing a series of image formation processes.

[0021] That is, the developing device 12 has an appropriate known configuration, such as a developing roller that generates a toner brush with toner particles standing radially from its surface. The toner particles on the tip of the toner brush are attached to the latent image that is generated at a predetermined location on the surface of the photoreceptor 10A and moves around the circumference as the photoreceptor 10A rotates, passing through the developing position, thereby making the invisible latent image visible as a monochrome toner image.

[0022] Transfer device 13 is composed of two support rollers 15 and 16 arranged facing each other at a predetermined distance in the approximately vertical direction, and transfer belt 17, an endless belt, stretched between these support rollers 15 and 16. Transfer device 13 transfers the toner image on the outer peripheral surface of photoreceptor 10A to sheet S and transports sheet S with the transferred unfixed toner image downstream of transport path R1. That is, the portion of lower support roller 16 around which transfer belt 17 is wound is pressed against a location approximately diagonally below right of photoreceptor 10A, and the transfer position is set at the point where the surface of photoreceptor 10A and transfer belt 17 come into contact. Furthermore, upper support roller 15 is arranged just before the inlet of fixing device 11.

[0023] Photoconductor cleaning device 18 has either a blade (not shown) configured so that the blade edge at the tip thereof contacts the cleaning position on photoconductor 10A with a predetermined pressure, or a rotating brush that contacts the cleaning position and rotates in response to the rotation of photoconductor 10A, or both. Photoconductor cleaning device 18 removes toner and foreign matter remaining on the surface of photoconductor 10A after transfer.

[0024] The static eliminator is mainly composed of a lamp capable of emitting light of a predetermined intensity. This lamp irradiates the static elimination position with light for static elimination, thereby removing the charge on the surface of the photoreceptor 10A as it passes the static elimination position, and returning the surface potential of the photoreceptor 10A after it passes the transfer position to its initial state.

[0025] The fixing device 11 has a heating roller 31 incorporating an electric heater or the like as a heat source, and a pressure roller 32 disposed substantially horizontally opposite the heating roller 31 and pressed against the heating roller 31. When the heating roller 31 is driven to rotate by a driving source such as a motor (not shown), the pressure roller 32 in contact with the heating roller 31 is also rotated, and a predetermined heating temperature and pressure are maintained at the point where the two rollers 31, 32 come into contact, forming a nip portion for fixing the toner image onto the sheet.

[0026] In the figure, reference numeral 20 denotes a toner storage container such as a toner bottle that contains new or fresh toner, and a toner transport path (not shown) is formed from this toner storage container 20 to the developing device 12. When the developing device 12 consumes its own toner for development and runs short of toner, new toner is replenished from the toner storage container 20 to the developing device 12.

[0027] Below the image forming apparatus main body 2, there is provided a paper feeder 3 that allows a sheet size to be alternatively selected automatically or manually by the user depending on the size of the document to be read. That is, the paper feeder 3 has a plurality of paper feed trays 51, 51 stored and arranged in multiple stages within the paper feeder 3 as sheet storage means, and each paper feed tray 51, 51 is configured to be able to be individually pulled out of the paper feeder 3, so that each paper feed tray 51 can be set with sheets for that tray and replenished with an appropriate number of sheets. Each paper feed tray 51, 51 is loaded with and stores a large number of sheets S of different paper types (sheet types) having various sheet sizes and oriented lengthwise and widthwise relative to the sheet transport direction.

[0028] An opening / closing member 67 that constitutes a manual feed tray is disposed on one side of the device body. The opening / closing member 67 is configured to be able to open and close between a vertical storage position shown by the dashed lines in Fig. 1 and an open position shown by the solid lines, centered on a rotation shaft 67d (see Figs. 3A-3C) at the front end (the left end in Fig. 1).

[0029] A feed roller 71, a pickup roller 72, a friction pad 76, and the like, which serve as manual feeding means, are disposed between the opening / closing member 67 and the image forming apparatus main body 2. Here, the pickup roller 72 is an example of a sheet feeding member that abuts on the upper surface of the sheets stacked on the stacking portion (sheet stacking ribs 83a and 83b described later) of the opening / closing member 67, and feeds out the sheets.

[0030] The feed roller 71 is an example of a feeding member that contacts the upper surface of a sheet fed from a pickup roller 72, which is a sheet feeding member, and feeds the sheet further downstream. The friction pad 76 is an example of a separating member that cooperates with the feed roller 71 to separate the sheets one by one. The friction pad 76 will be described later.

[0031] By this manual feed means, the sheet S set on the opening / closing member 67 is transported via the manual feed path R2 to the image forming apparatus main body 2. The opening / closing member 67, the feed roller 71, the pickup roller 72, and the friction pad 76 constitute a manual feed section (feed means).

[0032] Further, the image forming apparatus main body 2 is provided with a sheet inverting device 42 having an inverting conveying path (hereinafter also referred to as "inverting conveying path") R3 constituting a sheet front / back inverting means for inverting the sheet S on one side of which an image has been formed and fixed in the image forming unit. Here, the apparatus main body is a broad conceptual term including the apparatus main bodies of the image forming apparatus main body 2 and the sheet feeding device 3.

[0033] A plurality of pairs of rollers 66 that are rotationally driven by a driving means (not shown), guide members that are provided opposite to each other, and the like are arranged inside the sheet reversing device 42. The downstream end of the reversing conveying path R3 is connected to the conveying path R1 between the upper sheet conveying means 7' (pair of gripping rollers) and the pair of registration rollers 21, and a junction conveying path (hereinafter also referred to as a "junction conveying path" or a "junction portion") is formed on the downstream side including the connecting portion.

[0034] The configuration of the manual paper feed path R2 will be described in detail later, but it should be noted that both the conveying path R1 and the reverse conveying path R3 are made up of guide members that face each other at a predetermined distance, as shown appropriately.

[0035] The document reading device 4 has a reading device main body 4A that forms its framework, and a contact glass 57 is arranged over a predetermined range on the top surface of this reading device main body 4A. Inside the reading device main body 4A, there is housed reading means that optically reads the document image by scanning a predetermined range on the surface of the contact glass 57, and this reading means is mainly composed of at least a first traveling body 53, a second traveling body 54, an imaging lens 55, and a reading sensor 56 that is, for example, a CCD.

[0036] Furthermore, the document reading device 4 is provided with a document pressing plate 58 on the top surface of the reading device main body 4A, which is configured to be able to open and close between a closed position that covers the contact glass 57 and an open position that opens the contact glass 57. That is, the document pressing plate 58 is formed with dimensions larger in length and width than the contact glass 57, and one end of the document pressing plate 58 is supported on the top surface of the reading device main body 4A by a hinge (not shown) so as to be able to open and close freely.

[0037] ● Operation of the copier Based on the above-described configuration, the operation of the copier 1 will be described. First, when copying an original with the copier 1, the user manually opens the original presser plate 58 of the original reading device 4 from the closed position to the open position, places and sets the original on the contact glass 57, and then manually operates the original presser plate 58 in the closing direction, causing the original presser plate 58 to press down from above on the original set on the contact glass 57. With this operation, the original is brought into close contact with the contact glass 57 and spread out flat, and the original is fixed on the glass 57 so that the surface of the original can be read accurately.

[0038] When the user presses and turns on a start switch provided on an operation screen unit (not shown) that is pre-installed in the copier 1, the reading operation of the document reading device 4 is immediately started, and the first traveling body 53 and the second traveling body 54 are moved by a drive mechanism (not shown). Then, light from a light source of the first traveling body 53 is irradiated onto the document, and the light reflected from the document surface is directed towards the second traveling body 54, and this reflected light is reflected by a mirror of the second traveling body 54 and input to the reading sensor 56 via the imaging lens 55. As a result, the image of the document is photoelectrically converted and read by the reading sensor 56.

[0039] Furthermore, as described above, when the start switch is turned on, photoconductor 10A of photoconductor unit 10 starts to rotate, and an operation of forming a toner image on photoconductor 10A based on the scanned document image is initiated. That is, as photoconductor 10A rotates, predetermined locations on the outer peripheral surface of photoconductor 10A pass through positions set between charging device 14, exposure device 47, developing device 12, transfer device 13, photoconductor cleaning device 18, and static eliminator, and are sequentially charged to a predetermined charge state, a latent image is formed, a visible toner image is formed, and the latent image is transferred to sheet S, after which residual toner is removed and the charged state is released, completing one cycle. The cycle continues for a predetermined period so that a toner image is formed within a predetermined length of the outer peripheral surface in the direction of rotation of photoconductor 10A depending on the size of the image to be formed.

[0040] By pressing the start switch, one sheet S is conveyed to conveyance path R1 via a predetermined sheet conveyance path by the operation of sheet conveyance device 5 attached to the paper feed stage from paper feed tray 51 of the paper feed stage in which sheets S selected automatically or manually in paper feed device 3 are stored. This sheet S is conveyed approximately vertically upward on conveyance path R1 in image forming apparatus main body 2 by conveyance rollers or the like, and the leading edge of sheet S hits a portion immediately before the nip portion of registration roller pair 21 and stops temporarily.

[0041] On the other hand, in the case of manual paper feed, the sheet S set on the opening / closing member 67 is first fed out by the rotation of the manual feed tray pickup roller 72. If multiple fed sheets S are stacked, the sheets S are separated one by one by the feed roller 71 and the friction pad 76 and conveyed to the manual paper feed path R2. The sheet S conveyed to the manual paper feed path R2 is further conveyed to the conveyance path R1, and the leading edge of the sheet S hits a portion immediately before the nip portion of the registration roller pair 21 and stops temporarily.

[0042] The pair of registration rollers 21 then starts rotating at the precise timing that matches the relative movement of the toner image on the rotationally driven photoreceptor 10A, and feeds the stopped sheet S to the transfer position. As a result, the toner image is transferred onto the sheet S by the transfer device 13.

[0043] The sheet S onto which the unfixed monochrome toner image has been transferred is transported to the fixing device 11 by the transfer belt 17 of the transfer device 13, which forms part of the transport path R1, and passes through a nip formed by the fixing device 11. The nip applies a predetermined amount of heat and pressure, fixing the image onto the sheet S. The sheet S with the fixed image is guided by a switching claw 34 toward the transport path R1 leading to the paper discharge tray 9, and is discharged onto the paper discharge tray 9 by each of the discharge rollers 35 to 38, and stacked on the paper discharge tray 9. The user can then remove the sheets stacked on the paper discharge tray 9 from an open area on the front side of the device, between the paper discharge tray 9 and the document reading device 4.

[0044] Furthermore, when the double-sided copy mode is selected by the user's setting input, the sheet S with the image fixed on one side is conveyed to the sheet inverting device 42 side by the switching claw 34. Thereafter, the sheet S is reciprocated on the inverting conveying path R3 by a plurality of pairs of rollers 66 and a guide member (not shown) in the sheet inverting device 42, and the sheet surface is inverted upside down.

[0045] The inverted sheet S is returned to the conveying path R1 from a position located in front of the photosensitive unit 10 via the registration roller pair 21, and is conveyed on this conveying path R1 and led to the transfer position again. Then, after an image is transferred and fixed on the back side of the sheet S, the sheet is finally discharged onto the paper discharge tray 9 by the discharge rollers 35 to 38. Here, the registration roller pair 21 functions as a registration means for correcting the posture of the sheet conveyed by the sheet conveying means 7, 7', the manual feed means, and the sheet inverting device 42.

[0046] ●Details of the sheet feeding device

[0047] 2A and 2B show sheet feeding device 8. This sheet feeding device 8 has a manual paper feed section (opening / closing member 67, feed roller 71, pickup roller 72, friction pad 76) and a guide member 74. Opening / closing member 67 has a pair of left and right arc-shaped arms 67a, 67b. The pair of arc-shaped arms 67a, 67b are slidably inserted into a pair of left and right guide holes formed on the side of main body 2 of copier 1 (the side of sheet inverting device 42).

[0048] A handle hole 67c is formed in the upper end (lower end in FIG. 2B) of the opening / closing member 67. During manual paper feeding, the opening / closing member 67 can be opened from the vertically stored state shown by the dashed line in FIG. 1 by hooking a fingertip on the handle hole 67c as shown by the solid line in FIG.

[0049] With the opening / closing member 67 open, the tip bent portions 67a1, 67b1 of the arcuate arms 67a, 67b engage with the inside of the guide holes on the side of the main body 2. This holds the opening / closing member 67 in the open state shown in Figures 2A and 2B.

[0050] A plurality of sheet stacking ribs 83a and 83b extending in the sheet feeding direction are provided on the upper surface (inner surface of the exterior surface 83) of the opening / closing member 67. The sheet stacking ribs 83a and 83b function as a stacking portion for sheets (particularly the front end portions of the sheets).

[0051] That is, the sheet stacking ribs 83a, 83b are configured so that the leading ends of the sheets stacked on the opening / closing member 67 can be placed on the upper edges of the sheet stacking ribs 83a, 83b. The sheet stacking ribs 83a, 83b reduce friction in the sheet feeding direction and also improve the rigidity of the opening / closing member 67. Conventional sheet feeding devices are not provided with such sheet stacking ribs, and the upper surface of the opening / closing member 67 is often configured as a flat surface.

[0052] A pair of left and right side regulating plates 69 are disposed upstream of the sheet stacking ribs 83a and 83b in the sheet feeding direction. The side regulating plates 69 are slidably movable symmetrically in the left and right directions (arrow directions) in FIG. 2B by a conventionally known moving mechanism using a pinion gear and a rack gear.

[0053] When the opening / closing member 67 is open, the front end of the opening / closing member 67 is adjacent to a guide member 74 on the side of the apparatus main body 2. A feed roller 71 and a pickup roller 72 are disposed on the guide member 74.

[0054] A bottom plate pad 68 is disposed at the front end (downstream end in the sheet feeding direction) of the opening / closing member 67 so as to face the pickup roller 72 (FIGS. 3A-3C). The bottom plate pad 68 can be made of a material with a high friction coefficient, such as urethane rubber (rubber hardness 80°). The bottom plate pad 68 corresponds to a sheet delivery member-side separating member.

[0055] An inclined portion 67f is formed at the front end (at the center in the width direction) of the opening / closing member 67 adjacent to the downstream side of the bottom plate pad 68. The inclined portion 67f lifts the front end of the sheet S transported downstream by the pickup roller 72 toward the feed roller 71.

[0056] 2C, feed roller 71 and pickup roller 72 are supported by a feed shaft 78. The rotation of feed shaft 78 is transmitted to feed roller 71, and the rotation of feed roller 71 is transmitted to pickup roller 72 via an idler gear 79.

[0057] The end of the feed shaft 78 opposite the feed roller 71 is supported by the housing of the copier 1. A drive unit for the feed shaft 78 is connected to this end. The drive unit rotates the feed roller 71 and the pickup roller 72, allowing the sheet S to be fed.

[0058] The feed roller 71, pickup roller 72, and idler gear 79 are rotatably supported by a sheet feed holder 73 serving as a support member. A height detection member provided on the sheet feed holder 73 can detect the presence and height of a sheet placed on the sheet stacking ribs 83a and 83b of the opening / closing member 67.

[0059] Based on the detection result, the pickup roller 72 is configured to move up and down between the lowered position shown in Fig. 3A and the raised position shown in Fig. 3B so as to correspond to the height of the sheet. At the raised position shown in Fig. 3B, sheets can be stacked or added on the opening / closing member 67.

[0060] A rectangular notch 74c is formed in the outer end (front end) of the guide member 74. This notch 74c is located below the pickup roller 72. When the opening / closing member 67 is opened outward about the pivot shaft 67d from the broken line to the position shown by the solid line in FIG. 1 during manual paper feeding, the bottom plate pad 68 at the front end of the opening / closing member 67 can be received in the notch 74c.

[0061] As shown in Figures 4A to 4C, guide member 74 supports receiving table 75 having friction pad 76 so that it can swing up and down. Friction pad 76 is fixed to the upper surface of receiving table 75 with an adhesive or the like. When multiple sheets are fed in a stack between friction pad 76 and feed roller 71, only the topmost sheet is fed downstream by feed roller 71 due to the difference in friction.

[0062] The receiving tray 75 has a pair of left and right swing shafts 75a, 75b. Meanwhile, the guide member 74 has a pair of left and right receiving tray holders 74a, 74b that protrude outward (toward the front). The swing shafts 75a, 75b are rotatably supported by the receiving tray holders 74a, 74b. As shown in FIGS. 4A to 4C, a bottom plate pad 68 is disposed between the pair of left and right swing shafts 75a, 75b in a direction perpendicular to the sheet feeding direction (the left-right direction in the drawings, which is also the direction in which the sheet stacking ribs 83a, 83b are arranged side by side).

[0063] As shown in Fig. 3C, the upper end of a compression coil spring 77 abuts against the underside of receiving table 75. Compression coil spring 77 biases receiving table 75 to rotate clockwise around pivot shafts 75a and 75b (as shown in Fig. 3C) This allows friction pad 76 to be pressed against feed roller 71 substantially perpendicular to the sheet conveyance direction.

[0064] The friction pad 76 can be made of a material with a high friction coefficient, such as urethane rubber (e.g., rubber hardness 80°). The friction pad 76 is pressed against the roller by a compression coil spring 77 at a constant pressure (e.g., 100 g to 250 g / cm). 2 ) to pressurize the feed roller 71, it is possible to maintain good sheet separation properties, good sheet followability, and suppress vibration of the friction pad 76.

[0065] Specifically, the coefficient of friction between the friction pad 76 and the sheet S can be set to be higher than the coefficient of friction between the sheets S themselves, and lower than the coefficient of friction between the feed roller 71 and the sheet S. This makes it possible for two or more sheets S to be separated and fed one by one downstream, even if they enter the nip portion between the friction pad 76 and the feed roller 71.

[0066] ●Position of the swing axis of the support base 3C, the pair of left and right swing shafts 75a, 75b of the receiving table 75 are located in a first recess 67e formed on the inner surface of the opening / closing member 67 at the downstream end in the sheet feeding direction. That is, the swing shafts 75a, 75b of the receiving table 75 overlap with the opening / closing member 67 in the open state when viewed from the axial direction.

[0067] 2C, the swing shafts 75a and 75b of the receiving tray 75 and the receiving tray holders 74a and 74b that support them are located in the space between the sheet stacking ribs 83a (right side) and between the sheet stacking ribs 83b (left side). This makes it possible to position the rotation shaft 67d of the opening / closing member 67 as close as possible to the device main body while avoiding interference between the swing shafts 75a and 75b of the receiving tray 75 and the receiving tray holders 74a and 74b. Furthermore, because the swing shafts 75a and 75b and the receiving tray holders 74a and 74b are located below the sheet passing area of ​​the sheets S, the sheet passing performance of the sheets S is not impaired.

[0068] 3D is a diagram showing the positional relationship between the nip tangent line L between the feed roller 71 and the friction pad 76 and the swing shaft 75a of the receiving base 75. The swing shaft 75a of the receiving base 75 for the friction pad 76 can be provided on the nip tangent line L, as shown in FIG.

[0069] This prevents the friction pad 76 from being subjected to a force in a direction that moves it away from the feed roller 71 when the feed roller 71 is driven. Also, the generation of abnormal noise due to vibration of the friction pad 76 can be prevented.

[0070] If the swing shaft 75a of the receiving table 75 is provided downstream of the nip of the friction pad 76 in the sheet feeding direction, the angle between the sheet S and the friction pad 76 increases when the receiving table 75 is lowered due to the entry of a sheet. This increases the load on the feed roller 71, resulting in a paper feed failure. Therefore, it is desirable to locate the swing shaft 75a upstream of the nip of the friction pad 76.

[0071] Vertical storage of opening and closing member 67 When manual paper feeding is not performed, the opening / closing member 67 can be stored vertically on the side of the apparatus main body 2 as shown in Figures 5A and 5B. When the opening / closing member 67 is rotated upward about the rotation shaft 67d to store the opening / closing member 67 vertically, the pickup roller 72 moves upward along the sheet stacking ribs 83a and 83b as shown in Figures 5A and 5B. As a result, the paper feed holder 73 tilts upward and to the right about the feed roller 71 (feed shaft 78).

[0072] 5A and 5B, when the paper feed holder 73 is tilted upward to the right, part of the outer periphery of the pickup roller 72 is housed (entered) in the second recess 83c of the sheet stacking ribs 83a, 83b. This allows the open / close member 67 to be stored vertically closer to the device body 2 than before, making it possible to downsize the copier 1 while maintaining paper feeding performance. In addition, because the second recess 83c can suppress the angle of tilt of the paper feed holder 73 upward to the right, it is possible to prevent the pickup roller 72 from interfering with surrounding components above it when downsizing the copier 1.

[0073] The pivot shaft 67d of the opening / closing member 67 is pivotably supported by a pair of left and right bearing portions 74d that protrude outward (toward the front) from the guide member 74. The bearing portions 74d are located in a first recess 67e formed on the inner surface of the opening / closing member 67. Therefore, when viewed from the axial direction, the bearing portions 74d overlap with the main body of the opening / closing member 67. Furthermore, the pivot shafts 75a, 75b and pedestal holders 74a, 74b of the pedestal 75 are also located in the first recess 67e formed on the inner surface of the opening / closing member 67, together with the bearing portions 74d (see FIG. 3C).

[0074] Conventionally, as shown in Patent Document 1 (FIGS. 7 and 8), for example, the tray opening / closing shaft 3a was disposed at a position away from the opening / closing member 3 toward the device main body when viewed from the axial direction. This made it difficult to move the opening / closing member 3 toward the device main body when the opening / closing member 3 was stored vertically in the device main body.

[0075] In contrast to this, in this embodiment, the swing shafts 75a, 75b, cradle holders 74a, 74b, and bearings 74d of the cradle 75 overlap the main body (first recess 67e) of the opening / closing member 67 when viewed from the axial direction, so that the opening / closing member 67 can be positioned closer to the device main body 2 than before when stored vertically on the device main body 2 side. This makes it possible to reduce the size of the copier 1 while ensuring paper feeding performance.

[0076] While the present invention has been specifically described above based on the embodiments, it goes without saying that the present invention is not limited to the above embodiments and can be modified in various ways within the scope of the technical concept set forth in the claims. For example, in the above embodiments, the separating member is a friction pad, but the separating member may also be a separation roller.

[0077] <Additional Notes> Preferred embodiments of the present invention will be described below. <First aspect> The first aspect is a sheet feeding device comprising: an opening / closing member that can be opened and closed around a pivot axis relative to the device main body and has a stacking section on which sheets are stacked when open; a sheet feeding member that abuts against the upper surface of the sheets stacked on the stacking section to feed the sheets; a feeding member that abuts against the upper surface of the sheets fed from the sheet feeding member to feed the sheets; a feeding means that has a separating member arranged opposite the feeding member to separate the sheets one by one; a guide member that guides the sheets fed from the feeding means; and a receiving table that holds the separating member and is swingably supported by the guide member, wherein the swing axis of the receiving table overlaps with the opening / closing member when open when viewed from its axial direction. <Second mode> A second aspect is the sheet feeding device of the first aspect, characterized in that the pivot axis of the receiving table is located in a first recess formed at the downstream end of the opening / closing member in the sheet feeding direction. <Third aspect> A third aspect is the sheet feeding device of the second aspect, characterized in that a bearing portion of the rotation shaft of the opening / closing member is located in the first recess of the opening / closing member. <Fourth aspect> A fourth aspect is a sheet feeding device according to any one of the first to third aspects, characterized in that the stacking section has a plurality of ribs formed extending in the sheet feeding direction, and the sheets are stacked on the upper edges of the ribs. <Fifth aspect> A fifth aspect is a sheet feeding device according to any one of the first to fourth aspects, characterized in that the pivot axis of the receiving table is located between adjacent ribs in a direction perpendicular to the feeding direction. <Sixth aspect> A sixth aspect is a sheet feeding device according to any one of the first to fifth aspects, characterized in that the sheet feed member is accommodated in the device main body by the closing operation of the opening / closing member, and a second recess is formed on the upper edge of the rib to accommodate the outer periphery of the sheet feed member. <Seventh aspect> A seventh aspect is a sheet feeding device of any one of the first to sixth aspects, characterized in that a receiving tray holding portion that holds the pivot axis of the receiving tray is located between adjacent ribs in a direction perpendicular to the feeding direction. <Eighth aspect> In an eighth aspect, a sheet feeding member-side separating member is disposed opposite the sheet feeding member and separates the sheets one by one, This is a sheet feeding device of any one of the first to seventh aspects, characterized in that the oscillating shafts are arranged in a pair so as to sandwich the sheet feed member side separation member in a direction perpendicular to the sheet feed direction. <Ninth aspect> A ninth aspect is an image forming apparatus including the sheet feeding device according to any one of the first to eighth aspects. [Explanation of symbols]

[0078] 1: Copy machine 2: Device body 3: Paper feeder 4: Document reader 4A: Reading device main body 5: Sheet conveying device 7: Sheet conveying means 7': Sheet conveying means 8: Sheet feeding device 9: Paper output tray 10: Photoconductor unit 10A: Photoconductor 11: Fixing device 12: Developing device 13: Transfer device 14: Charging device 15, 16: Support rollers 17: Transfer belt 18: Photoconductor cleaning device 20: Toner storage container 21: Registration roller pair 31: Heating roller 32: Pressure roller 34: Switching claw 35-38: Discharge rollers 42: Sheet inverting device 47: Exposure device 51: Paper feed tray 55: Imaging lens 56: Reading sensor 57: Contact glass 58: Document pressure plate 66: Roller 67: Opening and closing member 67a, 67b: Arc-shaped arms 67a1, 67b1: Tip bending portions 67c: Handle hole 67d: Rotation axis 67e: First recess 67f: Inclined portion 68: Bottom plate pad (sheet delivery member side separation member) 69: Side regulating plate 71: Feed roller (feed member) 72: Pickup roller (sheet delivery member) 73: Paper feed holder 74: Guide member 74a, 74b: cradle holder portion 74c: notch portion 74d: Bearing part 75: Receiving base 75a, 75b: swing shaft 76: friction pad (separation member) 78: Feed shaft 79: Idler gear 83: Exterior surface 83a, 83b: Seat loading ribs 83c: Second recess L: Nip tangent R1: Sheet transport path R1: Transport path R2: Paper feed path R3: Reversing transport path S: Seat [Prior art documents] [Patent documents]

[0079] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-178620

Claims

1. an opening / closing member that is openable and closable around a pivot shaft relative to the device body and has a stacking portion on which sheets are stacked when the opening / closing member is open; a sheet feeding means including a sheet feeding member that contacts the upper surfaces of the sheets stacked on the stacking section and feeds the sheets, a feeding member that contacts the upper surfaces of the sheets fed from the sheet feeding member and feeds the sheets, and a separating member that is disposed opposite the feeding member and separates the sheets one by one; a guide member for guiding the sheet fed from the feeding means; a receiving base that holds the separating member and is swingably supported by the guide member, A sheet feeding device, characterized in that the pivot shaft of said receiving table overlaps with said opening / closing member in an open state when viewed from the axial direction thereof.

2. 2. The sheet feeding device according to claim 1, wherein the pivot shaft of the receiving table is located in a first recess formed at a downstream end of the opening / closing member in the sheet feeding direction.

3. 3. The sheet feeding apparatus according to claim 2, wherein a bearing portion of the pivot shaft of the opening / closing member is located in the first recess of the opening / closing member.

4. 2. The sheet feeding device according to claim 1, wherein the stacking portion has a plurality of ribs formed to extend in the sheet feeding direction, and the sheets are stacked on the upper edges of the ribs.

5. 5. The sheet feeding device according to claim 4, wherein the pivot shaft of the receiving table is located between the ribs adjacent to each other in the direction perpendicular to the sheet feeding direction.

6. 5. A sheet feeding device according to claim 4, wherein the sheet feeding member is accommodated in the device main body side by the closing operation of the opening / closing member, and a second recess is formed on the upper edge of the rib to accommodate the outer periphery of the sheet feeding member.

7. 5. The sheet feeding device according to claim 4, wherein a receiving table holding portion for holding the pivot shaft of the receiving table is positioned between the ribs adjacent to each other in a direction perpendicular to the feeding direction.

8. a sheet-feeding-member-side separating member disposed opposite the sheet-feeding member and configured to separate the sheets one by one; 2. The sheet feeding device according to claim 1, wherein the pair of pivot shafts are disposed so as to sandwich the sheet feeding member side separating member in a direction perpendicular to the sheet feeding direction.

9. 9. An image forming apparatus comprising the sheet feeding device according to claim 1.

Images