Sheet Feeding Device

Abstract

To provide a sheet feeder capable of easily putting position relation in which a pressure plate is above an elevation member back into the original one even if the position relation is reversed, and suppressing the pressure plate or elevation member from being broken.SOLUTION: In a sheet feeder 1, an abutting member 40 abuts on an elevation member 60 at a first position and is pressed up together with a pressure plate body 32 when the elevation member 60 is below the pressure plate body 32, and moves up to move the pressure plate 31 from a non-feed position toward a feed position, and abuts on the elevation member 60 at the first position to move down together with the pressure plate body 32 when the elevation member 60 moves down to move the pressure plate 31 from the feed position toward the non-feed position. The abutting member 40 moves to the second position retracted from the elevation member 60 in response to abutting on the elevation member 60 when the elevation member 60 moves from above the pressure plate 31 toward below the pressure plate 31, and moves to the first position once the elevation member 60 moves to below the pressure plate 31.SELECTED DRAWING: Figure 13

Description

[Technical field]

[0001] The present invention relates to a sheet feeding device. [Background technology]

[0002] An example of a conventional sheet feeding device is disclosed in Patent Document 1. This sheet feeding device includes a pickup roller, an MP tray, and a link member.

[0003] The pickup roller feeds the sheet. The MP tray supports the sheet. The MP tray has a pressure plate that can move up and down between a feeding position where the top sheet is brought into contact with the pickup roller and a non-feeding position that is lower than the feeding position.

[0004] The pressure plate has a supported portion formed integrally therewith. The link member abuts against the supported portion of the pressure plate from below and is movable to move the pressure plate up and down. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2020-104973 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, in the conventional sheet feeding device described above, when the pressure plate moves up and down, for example, when removing a jammed sheet during feeding or when operation during feeding is suddenly stopped due to a power outage, there is a risk that the positional relationship of the pressure plate being on top and the link member being on the bottom will be reversed.

[0007] Furthermore, when attempting to move the link member from above the pressure plate to below the pressure plate in order to return the positional relationship between the pressure plate and the link member to its original position, the link member interferes with the supported portion of the pressure plate, making it impossible to return it to its original position, and in some cases, the pressure plate or link member may be damaged.

[0008] The present invention has been made in consideration of the above-mentioned conventional situation, and aims to provide a sheet feeding device that can be easily restored to its original position even if the positional relationship is reversed, with the pressure plate on top and the lifting member on the bottom, and that can prevent damage to the pressure plate or the lifting member. [Means for solving the problem]

[0009] The sheet feeding device of the present invention includes a feed roller for feeding a sheet, a feed tray for supporting sheets, the feed tray having a pressure plate that is vertically movable between a feed position where the top sheet is brought into contact with the feed roller and a non-feed position below the feed position; a lifting member that is in contact with the pressure plate from below and is movable to move the pressure plate up and down; The pressure plate includes a pressure plate body for supporting a sheet, a contact member supported by the plate body so as to be movable between a first position and a second position, wherein when the lifting member is located below the plate body, when the lifting member rises to move the plate from the non-feed position to the feed position, the contact member contacts the lifting member at the first position and is pushed up together with the plate body, and when the lifting member descends to move the plate from the feed position to the non-feed position, the contact member contacts the lifting member at the first position and descends together with the plate body, The abutment member is configured to move to the second position away from the lifting member in response to contact with the lifting member when the lifting member moves from above the pressure plate to below the pressure plate, and to move to the first position when the lifting member moves below the pressure plate.

[0010] In the sheet feeding device of the present invention, when the pressure plate moves up and down, for example, when removing a jammed sheet during feeding or when operation is suddenly stopped during feeding due to a power outage, there is a risk that the positional relationship of the pressure plate being on top and the lifting member being on the bottom will be reversed.

[0011] In this regard, in this sheet feeding device, the pressure plate has a pressure plate body and a contact member. That is, the pressure plate is divided into two parts. When the lifting member is moved from above the pressure plate to below the pressure plate in order to return the positional relationship between the pressure plate and the lifting member to the original position, the contact member moves to the second position in response to contact with the lifting member and retreats from the lifting member. As a result, the lifting member can reach a position below the pressure plate without being hindered by the contact member, and the contact member then moves to the first position, thereby eliminating the abnormality.

[0012] Therefore, the sheet feeding device of the present invention can be easily restored to its original position even if the positional relationship is reversed, with the pressure plate being on top and the lifting member being on the bottom, and damage to the pressure plate or the lifting member can be suppressed. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a partial cross-sectional view of an image forming apparatus according to a first embodiment, and mainly illustrates a state in which a feed tray is in an extended position and a pressure plate is in a non-feeding position. [Diagram 2] FIG. 2 is a perspective view of the feed tray and the lift arm, mainly showing a state in which the feed tray is in the extended position and the pressure plate is in the non-feeding position. [Diagram 3] FIG. 3 is a partial top view of the feed tray and the lift arm, mainly showing the state in which the feed tray is in the extended position. [Figure 4] FIG. 4 is a partial cross-sectional view similar to FIG. 1, mainly showing a state in which the feed tray is in the storage position. [Diagram 5] FIG. 5 is a partial cross-sectional view showing a state in which the feed tray is in the storage position and the rotation shaft of the pressure plate body is guided to the first rail end of the link rail, and is a diagram explaining the function of the tapered portion of the link rail. [Figure 6] FIG. 6 is a partial cross-sectional view similar to FIG. 1, mainly showing a state in which the feed tray is in the extended position and the pressure plate is in the feed position. [Figure 7] FIG. 7 is a side view showing the platen body, the contact member and the lifting arm, mainly showing the state in which the platen is in the non-feeding position. [Figure 8] FIG. 8 is a side view similar to FIG. 7, mainly showing the state in which the pressure plate is in the feed position. [Figure 9] FIG. 9 is a partial perspective view showing the plate body, the contact member and the lifting arm, mainly showing the state in which the plate is in the feed position. [Figure 10] FIG. 10 is an exploded perspective view of the pressure plate body, the torsion coil spring, and the contact member, showing the attitude of the contact member before it is assembled to the pressure plate body. [Figure 11] 11(a) and 11(b) are partial side views illustrating the procedure for assembling the contact members to the pressure plate body. [Figure 12] FIG. 12 is a side view similar to FIG. 7, showing a state in which the positional relationship is reversed, with the pressure plate on top and the lift arm on the bottom. [Figure 13] FIG. 13 is a side view similar to FIG. 7, showing a state in which the lifting arm has descended from the reversed positional relationship in which the pressure plate is above and the lifting arm is below, and the abutment member has swung to a second position in response to abutment with the lifting arm. [Figure 14] FIG. 14 is a side view similar to FIG. 7, illustrating the function of the guide portion of the contact member when the feeding tray moves from the deployed position to the accommodated position. [Figure 15] FIG. 15 is a partial cross-sectional view similar to FIG. 1 of an image forming apparatus according to a second embodiment, and mainly illustrates a state in which a torsion coil spring biases the pressure plate from a non-feeding position to approach a feeding position. [Figure 16] FIG. 16 is a side view similar to FIG. 7 of the image forming apparatus according to the second embodiment, and mainly illustrates a state in which the torsion coil spring biases the pressure plate from the non-feeding position to approach the feeding position. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] Hereinafter, first and second embodiments of the present invention will be described with reference to the drawings.

[0015] Example 1 As shown in Fig. 1, an image forming apparatus 1 of the first embodiment is an example of a specific aspect of a sheet feeding apparatus of the present invention. In Fig. 1, the front surface 9S side of a housing 9 is defined as the front of the apparatus, and the top surface side of the housing 9 is defined as the top of the apparatus, and the front-rear direction and the up-down direction are shown. The front-rear direction and the up-down direction shown in Fig. 2 and the subsequent figures are all shown corresponding to Fig. 1.

[0016] 2 and the like is perpendicular to the front-rear direction and the up-down direction. One side of the width direction DW1 shown in FIG.

[0017] 1, the image forming apparatus 1 includes a housing 9, a paper feed cassette 2C, an image forming unit 2, and a conveying unit (not shown). The housing 9 is substantially box-shaped and has an ejection tray 9T on its upper surface. The paper feed cassette 2C is located in the lower part of the housing 9 and stores multiple sheets in a stacked state.

[0018] The image forming unit 2 is located in the upper portion of the housing 9. The image forming unit 2 forms an image on a sheet by an electrophotographic method, a thermal method, an inkjet method, or another general image forming method.

[0019] A conveying unit (not shown) supplies sheets one by one from a paper feed cassette 2C to the image forming unit 2. An image is formed on the sheet by the image forming unit 2. Thereafter, the conveying unit (not shown) conveys the sheet on which the image has been formed and discharges it onto a discharge tray 9T.

[0020] The image forming apparatus 1 also includes a feed tray 3. The feed tray 3 is a multi-purpose tray for feeding a plurality of types of sheets SH having different sizes, thicknesses, etc. to the image forming unit 2.

[0021] The feed tray 3 is located on the front surface 9S side of the housing 9. The feed tray 3 is supported by the housing 9 so as to be rotatable between an extended position in which it extends forward from the front surface 9S as shown in Figs. 1 to 3, and a stored position in which it stands up along the front surface 9S of the housing 9 as shown in Fig. 4. The front surface 9S of the housing 9 is an example of the "side surface of the housing" in the present invention.

[0022] 1 to 3, when the feed tray 3 is in the deployed position, the upward surface of the feed tray 3 serves as a support surface 3A capable of supporting the sheets SH. The feed direction DF1 of the sheets SH supported on the support surface 3A is perpendicular to the width direction DW1 of the feed tray 3 and is inclined downward toward the rear.

[0023] In addition, when describing the shapes and the like of the multiple members constituting the feed tray 3, the attitude of the feed tray 3 in the deployed position is used as a reference in the up-down direction and the front-rear direction.

[0024] As shown in Fig. 1, the housing 9 has a feed tray housing section 90. The feed tray housing section 90 is recessed rearward from the upper portion of the front surface 9S. The other side of the feed tray housing section 90 in the width direction DW1, i.e., the inner wall located on the back side of the paper in Fig. 1, has an arm guide 90G having a generally elongated hole shape. Although not shown, the other side of the feed tray housing section 90 in the width direction DW1, i.e., the inner wall located on the front side of the paper in Fig. 1, also has an arm guide 90G.

[0025] 2 and 3, the image forming apparatus 1 includes link arms 91A and 91B. One end 91A1 of the link arm 91A has a shaft portion that protrudes to one side in the width direction DW1. One end 91B1 of the link arm 91B has a shaft portion that protrudes to the other side in the width direction DW1.

[0026] 1, one end 91B1 of the link arm 91B is connected to the housing 9 by inserting the shaft portion into an arm guide 90G of the feed tray housing portion 90. Although not shown in the figure, one end 91A1 of the link arm 91A is also connected to the housing 9 in a similar manner.

[0027] <Feed roller, separation roller, separation pad> The housing 9 has a roller support member 29 located below the feed tray housing portion 90, and a feed guide member 28 located below the roller support member 29. The image forming apparatus 1 has a feed roller 21, a separation roller 22, and a separation pad 22A.

[0028] The roller support member 29 rotatably supports the feed roller 21 and the separation roller 22. The roller support member 29 also supports the feed roller 21 and the separation roller 22 so that the positions of the rotation axes of the feed roller 21 and the separation roller 22 do not fluctuate. The lower portions of the feed roller 21 and the separation roller 22 are exposed below the roller support member 29.

[0029] The feed roller 21 is located above the support surface 3A and upstream of a downstream end 3D of the support surface 3A in the feed direction DF1. The separation roller 22 is located downstream of the downstream end 3D of the support surface 3A in the feed direction DF1.

[0030] As shown in FIG. 2, the feeding guide member 28 has a regulating surface 28A and a feeding surface 28B. The regulating surface 28A is a forward-facing surface extending in the width direction DW1. The regulating surface 28A is inclined so that its upper end is located rearward of its lower end. The regulating surface 28A faces the downstream end 3D of the support surface 3A from downstream in the feeding direction DF1. The feeding surface 28B is an upward-facing surface that is connected to the upper end of the regulating surface 28A. The feeding surface 28B extends toward the downstream in the feeding direction DF1.

[0031] The regulating surface 28A abuts against and stops the downstream end of the sheet SH supported on the support surface 3A in the feeding direction DF1. The feeding roller 21 feeds the uppermost sheet SH supported on the support surface 3A in the feeding direction DF1. The feeding surface 28B guides the sheet SH fed by the feeding roller 21.

[0032] The feeding guide member 28 supports the separation pad 22A so as to be exposed from the feeding surface 28B at a position directly below the separation roller 22. The separation pad 22A is pressed toward the separation roller 22.

[0033] The feeding roller 21, separation roller 22, and separation pad 22A feed the sheets SH supported on the support surface 3A one by one to the image forming unit 2. An image is formed on the sheets SH by the image forming unit 2. Thereafter, a conveying unit (not shown) conveys the sheets SH on which the images have been formed, and discharges them onto a discharge tray 9T.

[0034] <Detailed configuration of the feed tray> The feed tray 3 includes a feed tray main body 30 and a pressure plate 31 shown in FIGS. 1 to 4, and a sub-tray 30E shown in FIGS.

[0035] 1, the housing 9 supports the feed tray main body 30 so as to be swingable about an opening / closing axis X30. The opening / closing axis X30 is located on the lower end side of the feed tray housing portion 90 and extends in the width direction DW1.

[0036] As shown in FIGS. 2 and 3, the feeding tray body 30 has a flat plate portion 35, link rails 36A and 36B, and a sub-tray accommodating portion 37.

[0037] When the feeding tray 3 is in the deployed position shown in FIG. 1 etc., the flat portion 35 extends from the opening / closing axis X30 side toward the front with a gentle upward incline and also extends in the width direction DW1.

[0038] 4, the exterior surface of the flat plate portion 35 facing forward is flush with the front surface 9S, and constitutes part of the design surface of the housing 9. The surface of the flat plate portion 35 opposite to the exterior surface is defined as an inner surface 35T.

[0039] As shown in FIGS. 1 to 3, the link rails 36A, 36B are located at both ends in the width direction DW1 of the inner surface 35T of the flat plate portion 35, protrude upward, and extend in the feeding direction DF1.

[0040] 2, link rail 36A has a groove extending from first rail end 36A1 in feeding direction DF1, and link rail 36B has a groove extending from first rail end 36B1 in feeding direction DF1.

[0041] 3, the groove of link rail 36A extends to second rail end 36A2 opposite first rail end 36A1, and the groove of link rail 36B extends to second rail end 36B2 opposite first rail end 36B1.

[0042] As shown in FIG. 2, the sub-tray accommodation section 37 is located on the inner surface 35T side of the flat plate section 35, inside the link rails 36A, 36B in the width direction DW1.

[0043] As shown in FIG. 4, the sub-tray accommodation section 37 accommodates the sub-tray 30E when the feed tray 3 is in the accommodation position.

[0044] As shown in FIG. 1, the sub-tray 30E slides forward when the feed tray 3 is in the deployed position, thereby forming a part of the upstream side of the support surface 3A in the feed direction DF1.

[0045] 2 and 3, the pressure plate 31 has a pressure plate body 32 and a contact member 40. In other words, the pressure plate 31 is divided into two parts.

[0046] <Pressure plate body> The pressure plate body 32 is located on the inner surface 35T side of the feed tray body 30. The pressure plate body 32 is a substantially flat plate member extending in the feed direction DF1 and the width direction DW1. The pressure plate body 32 has rotation shafts 32A and 32B.

[0047] The rotating shafts 32A and 32B are located upstream of the pressure plate body 32 in the feed direction DF1, and protrude outward in the width direction DW1 from two corners spaced apart from each other in the width direction DW1. The rotating shafts 32A and 32B are centered on a third axis X32 extending in the width direction DW1.

[0048] The rotating shaft 32A passes through a groove in the link rail 36A and further passes through a shaft hole in the other end 91A2 of the link arm 91A, and is thereby supported by the other end 91A2 of the link arm 91A.

[0049] The rotating shaft 32B passes through a groove in the link rail 36B and further passes through a shaft hole in the other end 91B2 of the link arm 91B, and is thereby supported by the other end 91B2 of the link arm 91B.

[0050] The pivot shafts 32A, 32B are guided by grooves in the link rails 36A, 36B and are slidable between first rail ends 36A1, 36B1 and second rail ends 36A2, 36B2 of the link rails 36A, 36B.

[0051] 5, the link rail 36B has a tapered portion 36C. The tapered portion 36C is located on the first rail end 36B1 side. The tapered portion 36C bulges out from two opposing sides of the groove of the link rail 36B so as to approach each other.

[0052] The tapered portion 36C locally narrows the inner width of the groove of the link rail 36B near the pivot shaft 32B guided by the first rail end 36B1. As a result, the tapered portion 36C of the link rail 36B applies resistance to the pivot shaft 32B attempting to move from the first rail end 36B1 toward the second rail end 36B2.

[0053] Although not shown in the figures, link rail 36A also has tapered portion 36C, similar to link rail 36B. Tapered portion 36C of link rail 36A applies resistance to pivot shaft 32A attempting to move from first rail end 36A1 toward second rail end 36A2.

[0054] With this configuration, when the feed tray 3 is in the storage position shown in FIG. 4, as shown in FIG. 5, the pivot shaft 32B is guided by the first rail end 36B1 of the link rail 36B, and although not shown, the pivot shaft 32A is guided by the first rail end 36A1 of the link rail 36A, so that the feed tray 3 stands up along the front surface 9S of the housing 9.

[0055] In addition, when the feed tray 3 is in the expanded position shown in Figure 1 etc., the pivot axes 32A, 32B are guided by the second rail ends 36A2, 36B2 of the link rails 36A, 36B as shown in Figure 3, so that the feed tray 3 extends forward from the front surface 9S of the housing 9 as shown in Figure 1 and can support the sheets SH.

[0056] In this state, the upper surface of the pressure plate body 32 constitutes a part of the support surface 3A including the downstream end 3D, and supports the sheet SH.

[0057] The pressure plate 31 can move up and down between a feeding position in which the top sheet SH is brought into contact with the feeding roller 21, as shown in FIG. 6, and a non-feeding position that is lower than the feeding position, as shown in FIG. 1, by the pressure plate body 32 rotating around the third axis X32.

[0058] The position of the platen body 32 shown in Figures 7, 12 and 13 is the non-feeding position, whereas the position of the platen body 32 shown in Figures 8 and 9 is the feeding position.

[0059] As shown in FIGS. 2 and 3, the pressure plate body 32 has two pairs of contacted portions 33 and supporting portions .

[0060] One set of the contacted portion 33 and the supporting portion 34 is integral with the pressure plate body 32 at a corner located downstream in the feeding direction DF1 of the pressure plate body 32 and on one side in the width direction DW1.

[0061] The other set of the contacted portion 33 and the supporting portion 34 is integral with the pressure plate body 32 at a corner located downstream in the feeding direction DF1 of the pressure plate body 32 and on the other side in the width direction DW1.

[0062] The contacted portions 33 and the supporting portions 34 of one set and the contacted portions 33 and the supporting portions 34 of the other set have the same configuration but in opposite directions. Therefore, the configuration of the contacted portions 33 and the supporting portions 34 of one set will be described in detail, and the description of the contacted portions 33 and the supporting portions 34 of the other set will be omitted.

[0063] 10, the contacted portion 33 is a portion recessed upward at the tip of the above-mentioned corner of the pressure plate body 32. The contacted portion 33 opens to one side in the width direction DW1 and also opens downstream in the feeding direction DF1.

[0064] The support portion 34 protrudes upward from one edge in the width direction DW1 of the pressure plate body 32, upstream in the feeding direction DF1 from the abutted portion 33. The support portion 34 has a support shaft 34A, a cylindrical portion 34B, a slit 34C, and retaining pieces 34D and 34E.

[0065] The support shaft 34A is a cylinder that protrudes to one side in the width direction DW1 from a vertical middle portion of the support portion 34. The support shaft 34A is centered on a first axis X40 that extends in the width direction DW1.

[0066] The cylindrical portion 34B is a cylinder that surrounds the support shaft 34 with the first axis X40 as its center and protrudes slightly from the support portion 34 to one side in the width direction DW1.

[0067] Slit 34C is formed by cutting out a part of cylindrical portion 34B near contact portion 33. Locking pieces 34D and 34E are small pieces protruding radially outward from first axis X40 from two separate points on the tip edge of cylindrical portion 34B.

[0068] <Contact member and torsion coil spring> 2 and 3, the pressure plate 31 has two contact members 40. The contact member 40 located on one side in the width direction DW1 and the contact member 40 located on the other side in the width direction DW1 have the same configuration but on opposite sides. For this reason, the configuration of the contact member 40 located on one side in the width direction DW1 will be described in detail, and a description of the contact member 40 located on the other side in the width direction DW1 will be omitted.

[0069] 10, the pressure plate 31 has a torsion coil spring 40S located on one side in the width direction DW1, and a torsion coil spring 40S (not shown) located on the other side in the width direction DW1. The torsion coil spring 40S is an example of the "first biasing means" of the present invention.

[0070] The torsion coil spring 40S located on one side in the width direction DW1 and the torsion coil spring 40S located on the other side in the width direction DW1 have the same configuration but on opposite sides. Therefore, a description of the torsion coil spring 40S located on the other side in the width direction DW1 will be omitted.

[0071] The torsion coil spring 40S is disposed between the support portion 34 of the pressure plate body 32 and the abutment member 40. More specifically, the torsion coil spring 40S is attached to the support portion 34 so that the coil portion is surrounded by the cylindrical portion 34B with the coil portion being inserted around the support shaft 34A.

[0072] In this state, the slit 34C locks one end 40S1 of the torsion coil spring 40S. The other end 40S2 of the torsion coil spring 40S protrudes to one side in the width direction DW1.

[0073] The abutment member 40 is supported by the pressure plate body 32 so as to be swingable about a first axis X40. More specifically, the abutment member 40 has a supported portion 45, an extending portion 43, a first abutment portion 41, a second abutment portion 42, and a guide portion 46.

[0074] As shown in Figures 11(a) and (b), the supported portion 45 is supported by the pressure plate body 32 so as to be swingable around the first axis X40 by inserting the support shaft 34 of the pressure plate body 32, and engages the other end portion 40S2 of the torsion coil spring 40S.

[0075] 10, the extending portion 43 extends from the supported portion 45 in a radially outward direction of the first axis X40. The first contact portion 41 is located on the tip side of the extending portion 43. The tip of the first contact portion 41 is semicircular when viewed from the width direction DW1. The second contact portion 42 is adjacent to the first contact portion 41 on the tip side of the extending portion 43, and is a cylinder that protrudes toward the other side in the width direction DW1, i.e., toward the pressure plate body 32 side.

[0076] The guide portion 46 is a part of the outer flange connected to the supported portion 45, and protrudes radially outward from the first axis X40. The guide portion 46 has a guide surface 46A. The guide surface 46A is gently curved from the apex of the guide portion 46 toward the extension portion 43.

[0077] 11(a) and (b), the abutting member 40 has small pieces 44D and 44E. The small pieces 44D and 44E are connected to two separate points on an outer flange connected to the supported portion 45, extend to the other side in the width direction DW1, and then bend inwardly in the radial direction of the first axis X40.

[0078] The abutment member 40 is assembled to the support portion 34 in the following manner.

[0079] As shown in Fig. 10, the contact member 40 with the extension 43 facing upward is shallowly inserted into the support shaft 34, and the support shaft 34 engages the other end 40S2 of the torsion coil spring 40S as shown in Fig. 11(a). In this state, the small pieces 44D, 44E are located to one side in the width direction DW1 relative to the retaining pieces 34D, 34E.

[0080] Next, as shown in FIG. 11(b), the abutment member 40 is swung counterclockwise in the plane of the paper in FIG. 11 against the biasing force of the torsion coil spring 40S, and the small pieces 44D, 44E are moved to a position where they do not overlap with the anti-slip pieces 34D, 34E when viewed from the width direction DW1.

[0081] Next, the abutment member 40 is inserted deeply into the support shaft 34, and the small pieces 44D, 44E are moved to the other side of the width direction DW1 from the anti-slip pieces 34D, 34E, and then the abutment member 40 is swung clockwise in the plane of the paper in Figure 11 by the biasing force of the torsion coil spring 40S.

[0082] 7, the upper end of the second abutment portion 42 abuts against the abutted portion 33, and the abutting member 40 is positioned in the circumferential direction of the first axis X40. In this state, the small pieces 44D, 44E are positioned to overlap the retaining pieces 34D, 34E when viewed from the width direction DW1, and prevent the supported portion 45 from coming off the support shaft 34.

[0083] In this way, the abutting member 40 is supported by the pressure plate body 32 so as to be movable between a first position where the upper end of the second abutting portion 42 abuts against the abutted portion 33 as shown in Fig. 7, and a second position where the upper end of the second abutting portion 42 is spaced downward and forward from the abutted portion 33 as shown in Fig. 13. The torsion coil spring 40S biases the abutting member 40 toward the first position shown in Fig. 7.

[0084] The position of the abutment member 40 shown in Figures 2, 3, 8, 9, 12 and 14 is also the first position.

[0085] <Lifting mechanism> As shown in FIGS. 2 and 3, the image forming apparatus 1 includes a lifting mechanism 6 for vertically moving the pressure plate 31 between a non-feeding position and a feeding position.

[0086] The lifting mechanism 6 has a transmission shaft 69 extending in the width direction DW1. Although not shown, one end of the transmission shaft 69 in the width direction DW1 is connected to a driving source and a transmission mechanism (not shown). When a driving force is transmitted from the driving source and the transmission mechanism (not shown), the transmission shaft 69 rotates counterclockwise on the paper surface of FIG.

[0087] 2 and 3, the lifting mechanism 6 has two pairs of transmission gears 68 and a lifting arm 60. The lifting arm 60 is an example of the "lifting member" of the present invention.

[0088] One set of the transmission gear 68 and the lifting arm 60 is located behind the contact member 40 located on one side in the width direction DW1. The other set of the transmission gear 68 and the lifting arm 60 is located behind the contact member 40 located on the other side in the width direction DW1.

[0089] The transmission gear 68 and the lift arm 60 of one set and the transmission gear 68 and the lift arm 60 of the other set have the same configuration but in the opposite directions. Therefore, the configuration of the transmission gear 68 and the lift arm 60 of one set will be described in detail, and the description of the transmission gear 68 and the lift arm 60 of the other set will be omitted.

[0090] The transmission gear 68 is a sector-shaped gear and is rotatable integrally with the transmission shaft 69. The transmission gear 68 is biased by a tension coil spring 68S so as to rotate in a clockwise direction on the paper surface of Fig. 7. When a driving force from a driving source and a transmission mechanism (not shown) is transmitted to the transmission shaft 69, the transmission gear 68 rotates integrally with the transmission shaft 69 in a counterclockwise direction on the paper surface of Fig. 7.

[0091] 2 and 3, the lifting arm 60 is capable of swinging about a second axis X60 extending in the width direction DW1 forward of the transmission shaft 69. The lifting arm 60 has a sector gear 62, an arm portion 63, and an action portion 64.

[0092] The sector gear 62 has a plurality of gear teeth arranged in an arc shape centered on the second axis X60. The sector gear 62 meshes with a transmission gear 68.

[0093] The arm portion 63 extends forward in the radially outward direction of the second axis X60. The action portion 64 is formed on the tip side of the arm portion 63. The action portion 64 is located below the first contact portion 41 of the contact member 40 and is capable of contacting the first contact portion 41.

[0094] 7, the arm portion 63 swings to a position where it is inclined downward toward the front. At this time, the action portion 64 descends while abutting against the abutment member 40 of the pressure plate 31 from below, thereby lowering the pressure plate body 32 of the pressure plate 31 and further moving downward away from the abutment member 40.

[0095] 8, the arm portion 63 swings forward to a position where it is inclined upward. At this time, the action portion 64 abuts against the abutting member 40 of the pressure plate 31 from below, thereby lifting the pressure plate body 32 of the pressure plate 31.

[0096] In this manner, the lifting arm 60 is movable to move the pressure plate 31 up and down.

[0097] 2, 3, and 7 to 9, the image forming apparatus 1 is in a normal state with the pressure plate 31 on top and the lift arm 60 on the bottom. Here, the vertical relationship between the pressure plate 31 and the lift arm 60 is the relationship between the downstream end side of the pressure plate 31 in the feeding direction DF1 and the acting portion 64 of the lift arm 60.

[0098] However, as shown in FIG. 12, when the pressure plate 31 of the image forming apparatus 1 moves up and down, for example, when removing a jammed sheet SH during feeding or when operation is suddenly stopped during feeding due to a power outage or the like, the pressure plate body 32 of the pressure plate 31 in the non-feeding position may go below the action portion 63 of the lifting arm 60, which may reverse the positional relationship in which the pressure plate 31 is above and the lifting arm 60 is below.

[0099] The position of the lifting arm 60 shown by the dotted line in Figure 12 is the position to which the lifting arm 60 is raised most when the front cover constituting the front surface 9S of the housing 9 is opened to remove the jammed sheet SH, and the transmission shaft 69 is no longer restricted by a transmission mechanism (not shown), and the lifting arm 60 is raised most by the force of the tension coil spring 68S.

[0100] <Function of the contact member when the pressure plate is on top and the lift arm is on the bottom> In the case where the pressure plate 31 is on top and the lifting arm 60 is on the bottom, as shown in Figures 8 and 9, when the lifting arm 60 rises to move the pressure plate 31 from the non-feeding position to the feeding position, the abutting member 40 is at a first position where the upper end of the second abutting portion 42 abuts against the abutted portion 33, and the first abutting portion 41 abuts against the acting portion 64 of the lifting arm 60. This causes the abutting member 40 to be pushed up together with the pressure plate body 32. As a result, the pressure plate 31 moves to the feeding position.

[0101] 8 and 9 toward the non-feeding position shown in Fig. 7 etc., the abutment member 40 is in the first position where the upper end of the second abutment portion 42 abuts against the abutted portion 33, and the first abutment portion 41 abuts against the action portion 64 of the lifting arm 60 and descends together with the pressure plate body 32. When the pressure plate 31 moves to the non-feeding position and stops, the first abutment portion 41 also stops and moves away from the descending action portion 64.

[0102] <Function of the contacting parts when the positional relationship is reversed, with the pressure plate on top and the lift arm on the bottom> As shown in FIG. 12, when the pressure plate body 32 of the pressure plate 31 in the non-feeding position goes below the action portion 63 of the lifting arm 60, reversing the positional relationship of the pressure plate 31 on top and the lifting arm 60 on the bottom, the abutment member 40 acts as follows.

[0103] In other words, when the lifting arm 60 moves from above the pressure plate 31 to below the pressure plate 31, as shown in Figure 13, the action portion 64 of the lifting arm 60 descends while abutting against the first abutment portion 41 from above, thereby acting on the first abutment portion 41 with a downward pressing force.

[0104] 13 against the biasing force of the torsion coil spring 40S. That is, the abutment member 40 moves to the second position where it is retracted from the lifting arm 60 in response to the abutment with the lifting arm 60. This allows the lifting arm 60 to move down without being hindered by the first abutment portion 41 of the abutment member 40.

[0105] Then, when the action portion 64 of the lifting arm 60 moves downward away from the first abutment portion 41 and the lifting arm 60 moves downward below the pressure plate 31, as shown in FIG. 7, the abutment member 40 swings clockwise on the page of FIG. 7 due to the biasing force of the torsion coil spring 40S, and moves to the first position.

[0106] <Function of the guide part> When the positional relationship is reversed, with the pressure plate 31 on top and the lifting arm 60 on the bottom as shown in FIG. 12, and the feed tray 3 moves from the deployed position to the stored position as shown in FIG. 14, the guide portion 46 acts as follows.

[0107] That is, the apex of the guide portion 46 moves above the action portion 64 of the raised lift arm 60. Then, the guide surface 46A slides against the action portion 64 of the lift arm 60 to guide the lift arm 60 below the guide portion 46.

[0108] At this time, the pressing force acting on the guide surface 46A from the action portion 64 acts to slide the rotation shafts 32A, 32B of the pressure plate body 32 toward the first rail ends 36A1, 36B1 of the link rails 36A, 36B. As a result, the feeding tray 3 can be smoothly moved to the storage position.

[0109] <Action and effect> In the image forming apparatus 1 of the first embodiment, as shown in FIG. 12, when the pressure plate 31 moves up and down, for example, when removing a jammed sheet SH during feeding or when operation during feeding is suddenly stopped due to a power outage or the like, there is a risk that the positional relationship in which the pressure plate 31 is on top and the lift arm 60 is on the bottom will be reversed.

[0110] In this regard, in the image forming apparatus 1, the pressure plate 31 has a pressure plate body 32 and a contact member 40. That is, the pressure plate 31 is divided into two parts. Then, as shown in FIG. 13, when the lift arm 60 is moved from above the pressure plate 31 to below the pressure plate 31 in order to return the positional relationship between the pressure plate 31 and the lift arm 60 to the original position, the contact member 40 moves to the second position in response to the contact with the lift arm 60 and retreats from the lift arm 60. As a result, the lift arm 60 can reach a position below the pressure plate 31 without being hindered by the contact member 40, and the contact member 40 then moves to the first position, thereby eliminating the abnormality.

[0111] Therefore, in the image forming apparatus 1 of the first embodiment, even if the positional relationship is reversed such that the pressure plate 31 is on top and the lift arm 60 is on the bottom, the image forming apparatus 1 can be easily returned to the original position, and damage to the pressure plate 31 or the lift arm 60 can be prevented.

[0112] 10 and 11, in the image forming apparatus 1, the pressure plate 31 has a torsion coil spring 40S disposed between the pressure plate body 32 and the contact member 40, which biases the contact member 40 toward the first position. With this configuration, the contact member 40 is biased by the torsion coil spring 40S, and the upper end of the second contact portion 42 is restricted by the contacted portion 33 of the pressure plate body 32, so that the contact member 40 is held in the first position with high reliability. Then, after the contact member 40 moves to the second position in response to the contact with the lift arm 60, it can return to the first position with high reliability.

[0113] 9, the contact member 40 has a first contact portion 41 and a second contact portion 42 protruding from the first contact portion 41 toward the pressure plate body 32 in the width direction DW1. That is, the first contact portion 41 and the second contact portion 42 are adjacent to each other in the width direction DW1. This allows the contact member 40 to suppress a transmission loss of the force transmitted from the lifting arm 60, which rises to move the pressure plate from the non-feeding position to the feeding position, to the pressure plate body 32.

[0114] In addition, in this image forming apparatus 1, the contact member 40 has a supported portion 45 and an extending portion 43. The first contact portion 41 is located at the tip side of the extending portion 43, and the second contact portion 42 is adjacent to the first contact portion 41 at the tip side of the extending portion 43. This allows the image forming apparatus 1 to simplify the first contact portion 41 and the second contact portion 42, and prevents the contact member 40 from becoming bulky in the width direction DW1. As a result, the image forming apparatus 1 can prevent an increase in size in the width direction DW1.

[0115] 7 and 13, in the image forming apparatus 1, the contact member 40 is supported by the pressure plate body 32 so as to be swingable about a first axis X40 extending in the width direction DW1. This makes it possible to prevent the contact member 40 from becoming bulky in the width direction DW1, and as a result, to prevent the image forming apparatus 1 from becoming large in size in the width direction DW1.

[0116] Furthermore, in this image forming apparatus 1, the lifting arm 60 has a sector gear 62, an arm portion 63, and an action portion 64, and is capable of swinging around a second axis X60. With this configuration, when the lifting arm 60 moves from above the pressure plate 31 toward below the pressure plate 31, the abutment member 40 smoothly moves to the second position in response to the abutment with the action portion 64 of the lifting arm 60, and can be reliably retracted from the lifting arm 60. As a result, damage to the lifting arm 60 can be suppressed.

[0117] 14, the contact member 40 has a guide portion 46. When the feeding tray 3 moves from the deployed position to the stored position, the apex of the guide portion 46 moves above the action portion 64 of the raised lift-down arm 60. The guide surface 46A slides against the action portion 64 of the lift-down arm 60 to guide the lift-down arm 60 below the guide portion 46.

[0118] As a result, the image forming apparatus 1 can prevent the positional relationship, in which the pressure plate 31 is on top and the lift arm 60 is on the bottom, from being reversed when the feed tray 3 moves from the deployed position to the housed position.

[0119] 5, the link rails 36A and 36B have a tapered portion 36C. This makes it possible to prevent the pressure plate 31 from dropping due to the resistance that the tapered portion 36C applies to the rotating shafts 32A and 32B when the feed tray 3 moves from the storage position to the deployment position. As a result, the image forming apparatus 1 can prevent the pressure plate 31 from slipping under the lift arm 60 and can also suppress impact noise caused by the pressure plate 31 dropping.

[0120] Example 2 15 and 16, in the image forming apparatus of the second embodiment, the feeding tray 3 has a torsion coil spring 30S. The torsion coil spring 30S is an example of the "second biasing means" of the present invention.

[0121] One end 30S1 of the torsion coil spring 30S is engaged with the downstream end in the feeding direction DF1 of the inner surface 35T of the feeding tray main body 30. The other end 30S2 of the torsion coil spring 30S protrudes away from the inner surface 35T as it moves downstream in the feeding direction DF1, and abuts against the pressure plate main body 32 from below.

[0122] Although not shown in the drawings, the other end 30S2 of the torsion coil spring 30S abuts against the center of the pressure plate body 32 in the width direction DW1 from below.

[0123] The torsion coil spring 30S presses the pressure plate body 32 upward, thereby biasing the pressure plate 31 from the non-feeding position toward the feeding position.

[0124] Other configurations of the second embodiment are similar to those of the first embodiment. Therefore, the same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted or simplified.

[0125] <Action and effect> In the image forming apparatus of the second embodiment, the torsion coil spring 30S changes the distance by which the pressure plate 31 approaches the feeding position from the non-feeding position according to the number of sheets SH supported by the feeding tray 3, that is, according to the increase or decrease in the weight of the sheets SH. When the pressure plate 31 moves up and down, for example, when removing a jammed sheet SH during feeding or when the operation during feeding is suddenly stopped due to a power outage or the like, the number of sheets SH supported by the feeding tray 3 is generally zero or very few. Therefore, the distance by which the pressure plate 31 biased by the torsion coil spring 30S approaches the feeding position from the non-feeding position becomes large. As a result, this image forming apparatus can suppress the reversal of the positional relationship in which the pressure plate 31 is on top and the lift arm 60 is on the bottom when the pressure plate 31 moves up and down.

[0126] In addition, in this image forming apparatus, when the feed tray 3 moves from the storage position to the deployment position, the other end 30S2 of the torsion coil spring 30S applies a biasing force to the pressure plate body 32 of the pressure plate 31, and slides against the pressure plate body 32 to provide resistance to the pressure plate 31. As a result, the image forming apparatus can suppress the impact noise caused by the pressure plate 31 falling.

[0127] In the above, the present invention has been described based on Examples 1 and 2. However, the present invention is not limited to the above Examples 1 and 2, and it goes without saying that the present invention can be modified as appropriate without departing from the spirit of the present invention.

[0128] In the first and second embodiments, the contact member 40 swings around the first axis X40 extending in the width direction DW1, but the present invention is not limited to this configuration. For example, the contact member may swing around the swing axis extending in the feeding direction to move between a first position and a second position lower than the first position and closer to the center in the width direction of the feeding tray. The contact member may also move linearly in the width direction of the feeding tray to move between the first position and a second position at the same height as the first position and closer to the center in the width direction of the feeding tray. [Industrial Applicability]

[0129] The present invention can be used in, for example, an image forming apparatus, an image reading apparatus, or a multifunction peripheral. [Explanation of symbols]

[0130] 1...sheet feeding device (image forming apparatus), SH...sheet 21: Feeding roller, 3: Feeding tray, 31: Pressure plate 60: lifting member (lifting arm), 32: pressure plate body, 40: contact member 40S: first biasing means (torsion coil spring), 41: first contact portion DW1: Width direction of the feeding tray, 42: Second contact portion, X40: First axis 45...Supported part, 43...Extension part, X60...2nd axis center 62... sector gear, 63... arm portion, 64... action portion 9…Housing, 9S…Side of the housing (front) 46...Guiding part, 91A, 91B...Link arm 91A1, 91B1...One end of the link arm 91A2, 91B2...other end of link arm X32…3rd axis, 32A, 32B…rotation axis 36A, 36B...Link rail 36A1, 36B1...first rail end, 36A2, 36B2...second rail end 36C... throttle-shaped portion, 30S... second biasing means (torsion coil spring)

Claims

1. A feed roller for feeding a sheet; a feed tray for supporting sheets, the feed tray having a pressure plate that is vertically movable between a feed position where the top sheet is brought into contact with the feed roller and a non-feed position below the feed position; a lifting member that is in contact with the pressure plate from below and is movable to move the pressure plate up and down; The pressure plate includes a pressure plate body for supporting a sheet, a contact member supported by the plate body so as to be movable between a first position and a second position, wherein when the lifting member is located below the plate body, when the lifting member rises to move the plate from the non-feed position to the feed position, the contact member contacts the lifting member at the first position and is pushed up together with the plate body, and when the lifting member descends to move the plate from the feed position to the non-feed position, the contact member contacts the lifting member at the first position and descends together with the plate body, a contact member configured to move to the second position away from the lifting member in response to contact with the lifting member when the lifting member moves from above the pressure plate to below the pressure plate, and to move to the first position when the lifting member moves below the pressure plate.

2. 2. The sheet feeding device according to claim 1, wherein the pressure plate has a first biasing means disposed between the pressure plate body and the contact member for biasing the contact member toward the first position.

3. the contact member includes a first contact portion that is brought into contact with the lifting member from below when the lifting member moves up to move the pressure plate from the non-feeding position toward the feeding position; 3. The sheet feeding device according to claim 1, further comprising: a second contact portion protruding from the first contact portion toward the pressure plate body in the width direction of the feeding tray, the second contact portion having an upper end that contacts the pressure plate body from below when the first contact portion contacts the lifting member from below.

4. the abutting member includes a supported portion supported by the pressure plate body so as to be swingable about a first axis extending in a width direction of the sheet tray; an extension portion extending radially outward from the supported portion to the first axis; The first contact portion is located on a tip side of the extension portion, The sheet feeding device according to claim 3 , wherein the second contact portion is adjacent to the first contact portion on the tip side of the extension portion.

5. 4. The sheet feeding device according to claim 1, wherein the contact member is supported by the pressure plate body so as to be swingable about a first axis extending in a width direction of the feeding tray.

6. The sheet feeding device described in any one of claims 1 to 5, wherein the lifting member has a sector-shaped gear centered on a second axis extending in the width direction of the feeding tray, an arm portion extending radially outward from the second axis, and an acting portion formed at the tip side of the arm portion and capable of abutting against the abutment member, and has a lifting arm that can swing around the second axis.

7. Equipped with a housing, the feed tray is supported by the housing so as to be movable between a storage position where the feed tray stands along a side surface of the housing and a deployed position where the feed tray extends in a direction intersecting the side surface and is capable of supporting a sheet; The sheet feeding device according to claim 1 , wherein the abutment member has a guide portion that guides the lifting member downward while sliding against the raised lifting member when the feed tray moves to the storage position.

8. A housing and a link arm having one end connected to the housing; the pressure plate body has a rotation shaft centered on a third axis extending in a width direction of the feed tray, the rotation shaft being supported by the other end of the link arm, the feed tray has a link rail that guides the pivot shaft, and is supported by the housing so as to be movable between a storage position in which the pivot shaft is guided by a first rail end of the link rail to stand along the side of the housing, and a deployed position in which the pivot shaft is guided by a second rail end of the link rail opposite to the first rail end to extend in a direction intersecting the side and be able to support a sheet; 8. The sheet feeding device according to claim 1, wherein the link rail has a tapered portion that applies resistance to the pivot shaft that attempts to move from the first rail end toward the second rail end.

9. 9. The sheet feeding device according to claim 1, wherein the feeding tray has a second biasing member for biasing the pressure plate from the non-feeding position to approach the feeding position.

Images