JP2022085139A - Sheet feeding device - Google Patents

Abstract

To provide a sheet feeding device capable of suppressing a defect in sheet feeding.SOLUTION: A sheet feeding device 1 comprises: a feed roller 21 which feeds a sheet SH in a feed direction DF1; a feed tray 3 which has a support surface 3A inclined downward from an upstream end 3U to a downstream end 3D in the feed direction DF1 to support the sheet SH, the feed tray 3 having a pressure plate 31 supported rotatably on an axis X31 of rotation extending in a width direction DW1 of the support surface 3A and moving up and down below the feed roller 21, and a top surface of the pressure plate 31 constituting a part of the support surface 3A including the downstream end 3D; energization means 60 which energizes the pressure plate 31 toward the feed roller 21; and a projection part 50 which is provided at the feed tray 3, and has an upper end located above the support surface 3A to support the sheet SH. The projection part 50 is provided at a position overlapping with the axis X31 of rotation in the feed direction DF1 or at a position upstream from the axis X31 of rotation in the feed direction DF1.SELECTED DRAWING: Figure 2

Description

The present invention relates to a seat feeding device.

Patent Document 1 discloses an example of a conventional sheet feeding device. This seat feeding device includes a pickup roller, an MP tray and a first spring.

The pickup roller feeds the seat in the feeding direction. The MP tray has a support surface. The support surface is inclined downward from the upstream end to the downstream end in the feeding direction to support the seat. Further, the MP tray has a pressure plate. The pressure plate is rotatably supported around the pressure plate rotation shaft portion. The pressure plate moves up and down below the pickup roller. The upper surface of the pressure plate constitutes a part of the support surface including the downstream end in the feeding direction. The first spring urges the pressure plate toward the pickup roller.

In this sheet feeding device, the pressure plate urged by the first spring rotates upward, and the uppermost sheet supported by the support surface is pressed against the pickup roller to feed the sheet.

On the other hand, Patent Document 2 discloses another example of the conventional sheet feeding device. This sheet feeding device includes a paper feed roller, a paper loading plate, and a convex portion, but does not include a pressure plate as disclosed in Patent Document 1.

The paper feed roller feeds the paper in the feeding direction. The paper loading plate has a support surface that supports the paper. The paper loading plate is moved up and down below the paper feed roller by the elevating device. The convex portion is provided on the paper loading plate. The convex portion supports the paper with its upper end located above the support surface. The convex portion is provided at a position close to the downstream end of the support surface in the feeding direction and at a position in front of the paper feed roller.

In this paper feeding device, the paper loading plate is raised, and the top-level paper supported on the support surface is pressed against the paper feed roller to feed the paper. At this time, the convex portion eliminates the curl of the convex stripe downward in the width direction of the support surface, thereby suppressing poor paper feeding.

Japanese Unexamined Patent Publication No. 2020-93922 Japanese Unexamined Patent Publication No. 2005-247537

By the way, in the sheet feeding device disclosed in Patent Document 1, the pressure contact load when the pickup roller feeds the uppermost sheet supported on the support surface is mainly determined by the force of the first spring pushing up the pressure plate. It varies depending on the number of sheets supported on the support surface and the load of the sheet's own weight that changes depending on the thickness. When the center of the sheet supported by the support surface in the feeding direction is curled into an upward ridge, the weight load of the curled sheet is likely to be concentrated on the pressure plate including the downstream end in the feeding direction on the support surface. .. As a result, in this sheet feeding device, the variation in the pressure contact load tends to increase, and it may be difficult to suppress the sheet feeding defect.

In this regard, it will be considered to apply the convex portion provided in the sheet feeding device disclosed in Patent Document 2 to the sheet feeding device disclosed in Patent Document 1. In this case, the convex portion is provided at a position close to the downstream end of the support surface of the MP tray in the feeding direction and at a position in front of the pickup roller. However, in this case, the rising of the pressure plate may cause the sheet to meander between the convex portion and the pickup roller, increasing the feeding resistance acting on the uppermost sheet. As a result, even in the sheet feeding device disclosed in Patent Document 1 to which the convex portion according to the above Patent Document 2 is applied, it may be difficult to suppress the defective feeding of the sheet.

The present invention has been made in view of the above-mentioned conventional circumstances, and an object of the present invention is to provide a sheet feeding device capable of suppressing a sheet feeding defect.

The sheet feeding device of the present invention includes a feeding roller that feeds a sheet in the feeding direction, and a feeding roller.
A feed tray having a support surface that is inclined downward from the upstream end to the downstream end in the feed direction to support the seat, and is rotatably supported around a rotation axis extending in the width direction of the support surface. The feed tray has a pressure plate that moves up and down below the feed roller, and the upper surface of the pressure plate constitutes a part of the support surface including the downstream end.
An urging means for urging the pressure plate toward the feeding roller, and
Provided with a convex portion provided on the feed tray, the upper end of which is located above the support surface to support the sheet.
The convex portion is provided at a position overlapping the rotation axis in the feeding direction or at a position upstream of the rotation axis in the feeding direction.

In the sheet feeding device of the present invention, when the center of the sheet supported by the support surface in the feeding direction is curled into an upward ridge, the convex portion supports the center of the curled sheet in the feeding direction. As a result, it becomes difficult for the weight load of the curled sheet to concentrate on the pressure plate including the downstream end in the feeding direction on the support surface. As a result, in this sheet feeding device, it is possible to suppress an increase in variation in the pressure welding load.

Further, in this sheet feeding device, the convex portion is provided at a position where the convex portion overlaps with the rotation axis in the feeding direction, or at a position upstream of the rotation axis in the feeding direction, so that the pressure plate is provided. Even if the height rises, the sheet is unlikely to be bent in a meandering manner between the convex portion and the feeding roller, and the feeding resistance acting on the uppermost sheet is unlikely to increase.

Therefore, in the sheet feeding device of the present invention, it is possible to suppress a sheet feeding defect.

It is a partial perspective view of the image forming apparatus of an Example, and is the figure which mainly shows the feed tray in an open position. It is a partial cross-sectional view of the image forming apparatus of an Example, and is the figure which mainly shows the feed tray in an open position. It is the top view of the feed tray in an open position. It is a partial cross-sectional view of the image forming apparatus of an Example, and is the figure which mainly shows the feed tray in a closed position. It is a side view which shows the pressure plate and the urging means. It is sectional drawing of the feed tray in an open position, and is the figure which shows the state which the pressure plate is in the maximum rising position, and the convex part is in a protruding position. It is sectional drawing of the feed tray, and is the figure explaining the operation of the convex part and the convex part urging member. It is a figure which concerns on the image formation apparatus of the modification 1 and mainly shows a feed tray in an open position, and a convex part. It is a figure which concerns on the image forming apparatus of the modification 2 and mainly shows a feed tray in an open position, and a convex part.

Hereinafter, examples embodying the present invention will be described with reference to the drawings.

(Example)
As shown in FIG. 1, the image forming apparatus 1 of the embodiment is an example of a specific embodiment of the sheet feeding apparatus of the present invention. In FIG. 1, the front surface 9S side of the housing 9 is defined as the front side of the device, and the side that comes to the left when facing the front surface 9S is defined as the left side, and each direction of front / rear, left / right, and up / down is displayed. Then, each direction shown in each figure after FIG. 2 is displayed corresponding to each direction shown in FIG. Hereinafter, each component included in the image forming apparatus 1 will be described with reference to FIG. 1 and the like.

As shown in FIG. 1, the image forming apparatus 1 includes a housing 9, a paper cassette 2C, an image forming unit 2, and a transport unit (not shown). The housing 9 is a substantially box-shaped body, and a discharge tray 9T is recessed on the upper surface thereof. The paper cassette 2C is provided in a lower portion of the housing 9. The paper cassette 2C accommodates a plurality of sheets in a stacked state.

The image forming portion 2 is provided in an upper portion in the housing 9. The image forming unit 2 forms an image on a sheet such as a paper or an OHP sheet by an electrophotographic method, a thermal method, an inkjet method or other general image forming method.

The transport unit (not shown) supplies the sheets one by one from the paper feed cassette 2C to the image forming unit 2. An image of the sheet is formed by the image forming unit 2. After that, the transport unit (not shown) transports the sheet on which the image is formed and discharges it to the discharge tray 9T.

Further, the image forming apparatus 1 includes a feeding tray 3. The feeding tray 3 is a multipurpose tray for feeding a plurality of types of sheet SH having different sizes and thicknesses to the image forming unit 2.

The feed tray 3 is provided on the front surface 9S side of the housing 9. The feed tray 3 has an open position extending forward from the front surface 9S as shown in FIGS. 1 to 3 and a closed position extending forward along the front surface 9S of the housing 9 as shown in FIG. It is rotatably supported by the housing 9. The front surface 9S of the housing 9 is an example of the “side surface of the housing” of the present invention.

As shown in FIGS. 1 to 3, when the feed tray 3 is in the open position, the surface facing upward of the feed tray 3 is the support surface 3A. The feeding direction DF1 of the sheet SH supported by the support surface 3A is a direction in which the seat SH is gently downwardly inclined backward. The support surface 3A is inclined downward from the upstream end 3U of the feeding direction DF1 to the downstream end 3D to support the seat SH. The width direction DW1 of the support surface 3A is the left-right direction.

When explaining the shapes and the like of the plurality of members constituting the feed tray 3, the posture of the feed tray 3 in the open position is used as a reference in the vertical direction and the front-back direction.

As shown in FIGS. 1 and 2, the housing 9 has a feed tray accommodating portion 90 that is recessed backward from the front surface 9S. One ends of a pair of link levers 91A and 91B are rotatably supported on the left and right inner walls of the feed tray accommodating portion 90.

<Feeding roller, separation roller, separation pad>
As shown in FIG. 2, the housing 9 supports the roller support member 29 below the feed tray accommodating portion 90. Further, the housing 9 supports the feed guide member 28 below the roller support member 29. The image forming apparatus 1 includes a feeding roller 21, a separation roller 22, and a separation pad 22A.

The feeding roller 21 and the separating roller 22 are rotatably supported by the roller supporting member 29. Further, the feed roller 21 and the separation roller 22 are supported by the roller support member 29 so that the positions of the respective rotation axes do not change.

The lower portions of the feeding roller 21 and the separating roller 22 project downward from the roller support member 29.

As shown in FIGS. 2 and 3, the feeding roller 21 is located above the support surface 3A and upstream of the downstream end 3D of the support surface 3A in the feeding direction DF1. The separation roller 22 is located at substantially the same position as the feeding roller 21 in the vertical direction, and is located downstream of the feeding direction DF1 from the downstream end 3D of the support surface 3A.

As shown in FIG. 2, the feeding guide member 28 has a regulating surface 28A and a feeding surface 28B. The regulation surface 28A is a forward-facing surface extending in the vertical direction and the horizontal direction. The regulation surface 28A faces the downstream end 3D of the support surface 3A from the downstream side of the feeding direction DF1. The feeding surface 28B is connected to the upper end of the regulating surface 28A and is inclined upward toward the downstream side of the feeding direction DF1.

The regulation surface 28A hits the downstream end of the feeding direction DF1 of the sheet SH supported by the support surface 3A. The feeding roller 21 feeds the uppermost sheet SH supported by the support surface 3A to the feeding direction DF1. The feeding surface 28B guides the sheet SH fed by the feeding roller 21.

The separation pad 22A is supported by the feed guide member 28 so as to be exposed from the feed surface 28B at a position directly below the separation roller 22. The separation pad 22A is pressed toward the separation roller 22.

The separation roller 22 imparts a transport force toward the downstream side of the feeding direction DF1 to the sheet SH that has reached the nip position between the separation roller 22 and the separation pad 22A. If there are a plurality of sheet SHs that have reached the nip position, the separation pad 22A imparts a force to stop the transfer of the sheet SHs to the sheet SHs other than the sheet SHs that come into contact with the separation roller 22.

In this way, the feeding roller 21, the separating roller 22, and the separating pad 22A feed the sheet SH supported by the support surface 3A to the image forming unit 2 one by one. An image is formed on the sheet SH by the image forming unit 2. After that, the transport unit (not shown) transports the sheet SH on which the image is formed and discharges it to the discharge tray 9T.

<Detailed configuration of delivery tray>
As shown in FIGS. 1 to 3, the feed tray 3 has a feed tray main body 30, a pressure plate 31, a first sub tray 41, and a second sub tray 42. The first sub tray 41 and the second sub tray 42 are examples of the "sub tray" of the present invention.

As shown in FIG. 1, the feed tray main body 30 is swingably supported by the housing 9 around the opening / closing axis X30. The opening / closing axis X30 extends in the left-right direction on the lower end side of the feed tray accommodating portion 90.

The feed tray main body 30 has a flat plate portion 35, a pair of link rails 36A and 36B, and a pair of slide rails 37A and 37B.

The flat plate portion 35 extends from the opening / closing axis X30 side so as to gently ascend and incline forward and extends in the left-right direction in a state where the feeding tray 3 is in the open position shown in FIG.

The flat plate portion 35 constitutes a part of the design surface of the housing 9 with the exterior surface 35S facing forward thereof flush with the front surface 9S in a state where the feed tray 3 is in the closed position shown in FIG. .. The surface of the flat plate portion 35 opposite to the exterior surface 35S is the inner surface 35T.

As shown in FIGS. 1 to 3, the pair of link rails 36A and 36B are convexly provided on the left end side and the right end side of the inner surface 35T of the flat plate portion 35, and extend in the feeding direction DF1. A link hole 36H is formed in the pair of link rails 36A and 36B in an elongated hole shape extending in the feeding direction DF1.

The pair of slide rails 37A and 37B are projected inward in the left-right direction with respect to the pair of link rails 36A and 36B on the inner surface 35T of the flat plate portion 35, and extend in the feeding direction DF1.

The pressure plate 31 is provided on the inner surface 35T side of the feed tray main body 30. The pressure plate 31 is a substantially flat plate member extending in the feeding direction DF1 and in the left-right direction. A pair of shaft portions 32A and 32B are convexly provided on the two corner portions of the pressure plate 31 that are separated from the opening / closing shaft center X30 side. The pair of shaft portions 32A and 32B project so as to be separated from each other with respect to the rotation axis X31 extending in the left-right direction, which is the width direction DW1 of the support surface 3A.

The left shaft portion 32A is inserted into the link hole 36H of the left link rail 36A, and further inserted into the other end of the left link lever 91A. The right shaft portion 32B is inserted into the other end of the right link lever 91B, and further inserted into the link hole 36H of the right link rail 36B.

With such a configuration, with the feed tray 3 in the open position shown in FIG. 1 and the like, the posture of the feed tray main body 30 is determined, the position of the rotation axis X31 is determined, and the pressure plate 31 is the rotation axis. It is rotatably supported around X31.

The pressure plate 31 moves up and down below the feed roller 21 due to rotation around the rotation axis X31. The upper surface of the pressure plate 31 constitutes a part of the support surface 3A including the downstream end 3D.

As shown in FIGS. 1 to 3, the first sub tray 41 and the second sub tray 42 have a deployment position extending upstream of the feeding direction DF1 from the feeding tray main body 30, and a feeding tray as shown in FIG. It is movably supported by the feed tray main body 30 between the main body 30 and the storage position overlapping the pressure plate 31.

As shown in FIGS. 1 to 3, the first sub tray 41 is in the deployed position, and the downstream end of the feeding direction DF1 is supported by the upstream end of the feeding direction DF1 in the pair of slide rails 37A and 37B. .. The first sub tray 41 is located upstream of the pressure plate 31 in the feeding direction DF1, extends upward and inclined forward at a larger angle than the feeding tray main body 30, and extends in the left-right direction.

The second sub tray 42 is supported by the upstream end of the feeding direction DF1 in the first sub tray 41 and is rotatable around the rotation axis X42. In the deployed position, the second sub-tray 42 extends forward and tilts forward at a larger angle than the first sub-tray 41, and extends in the left-right direction.

The first sub-tray 41 and the second sub-tray 42 form a part of the support surface 3A including the upstream end 3U in the deployed position.

As shown in FIG. 4, the second sub-tray 42 rotates and overlaps with the first sub-tray 41, and then the first sub-tray 41 is guided by the pair of slide rails 37A and 37B and slides to the first sub-tray. The 41 and the second sub tray 42 move to a storage position that overlaps with the feed tray main body 30 and the pressure plate 31.

<Pair of side guides>
As shown in FIGS. 1 to 3, the image forming apparatus 1 further includes a pair of side guides 70A and 70B. The pair of side guides 70A and 70B are provided on the pressure plate 31 of the feed tray 3.

The pair of side guides 70A and 70B can approach and separate from each other in the width direction DW1 by a rack and pinion mechanism. The pair of side guides 70A and 70B positions the sheet SH supported by the support surface 3A with respect to the center of the width direction DW1 on the support surface 3A.

The positions of the pair of side guides 70A and 70B shown by solid lines in FIGS. 1 and 3 are the positions when the maximum size sheet SH that can be supported by the support surface 3A is positioned with respect to the center of the width direction DW1.

The positions of the pair of side guides 70A and 70B shown by the two-dot chain line in FIGS. 1 and 3 are the positions when the minimum size sheet SH that can be supported by the support surface 3A is positioned with respect to the center of the width direction DW1.

The distance between the width direction DW1 between one side guide 70A and the other side guide 70B when the minimum size sheet SH is positioned with respect to the center of the width direction DW1 is defined as the minimum distance W2.

<Means of urging>
As shown in FIG. 5, the image forming apparatus 1 further includes an urging means 60. FIG. 5 shows a set of urging means 60 located on the left side surface side of the pressure plate 41. Another set of urging means 60 is provided on the right side surface of the pressure plate 41, but the illustration is omitted because the configuration is the same. The urging means 60 has a tension coil spring 61, a transmission gear 62, and a transmission lever 63.

One end of the tension coil spring 61 is locked to a locking convex portion 28T provided above and behind the left side surface of the feed guide member 28.

The transmission gear 62 is rotatably supported on the lower end side of the left side surface of the feed guide member 28. The transmission gear 62 has a built-in damper (not shown) and has a locking piece 62T protruding in the outer diameter direction. The other end of the tension coil spring 61 is locked to the locking piece 62T.

The transmission lever 63 is rotatably supported above the transmission gear 62 on the left side surface of the feed guide member 28 and projects forward. The transmission lever 63 has gear teeth 63G that mesh with the transmission gear 62.

A contact portion 31T is convex downward at the downstream end of the feeding direction DF1 on the left side surface of the pressure plate 31. The front end of the transmission lever 63 supports the pressure plate 31 by abutting the contact portion 31T of the pressure plate 31 from below, and determines the inclined posture of the pressure plate 31.

The transmission gear 62 rotates clockwise in FIG. 5 due to the urging force of the tension coil spring 61. At this time, the transmission gear 62 rotates at a low speed by a damper (not shown). When the low-speed rotation of the transmission gear 62 is transmitted to the transmission lever 63, the transmission lever 63 rotates in the counterclockwise direction of FIG.

As a result, the transmission lever 63 raises its front end at a low speed to push up the contact portion 31T and raise the pressure plate 31. In this way, the urging means 60 urges the pressure plate 31 toward the feeding roller 21.

The pressure contact load when the feeding roller 21 feeds the uppermost sheet SH supported by the support surface 3A is mainly determined by the force F1 that the urging means 60 pushes up the pressure plate 31, and is supported by the support surface 3A. It varies depending on the weight load F2 of the sheet SH, which changes depending on the number and thickness of the sheet SH, and the frictional resistance acting between the front end of the transmission lever 63 and the abutting portion 31T of the pressure plate 31.

As shown in FIG. 6, a virtual straight line K1 extending in the feeding direction DF1 and connecting the downstream end 3D and the upstream end 3U of the support surface 3A is defined. The height of one end on the left side of the paper surface in the virtual straight line K1 changes depending on the vertical movement of the pressure plate 31.

FIG. 6 shows a state in which the pressure plate 31 is rotated to the maximum rising position, that is, a state in which the upper surface of the pressure plate 31 is in contact with the lower end of the feeding roller 21. In this state, one end on the left side of the paper surface in the virtual straight line K1 is at the highest position.

<Convex part>
As shown in FIGS. 1 to 3, the image forming apparatus 1 further includes a convex portion 50 provided on the feeding tray 3. The convex portion 50 is provided on the pressure plate 31 at a position upstream of the feeding direction DF1 from the rotation axis X31. That is, the convex portion 50 is provided at a position far upstream from the feeding roller 21 in the feeding direction DF1.

Further, the convex portion 50 is provided at the center of the width direction DW1 on the support surface 3A. As shown in FIG. 3, the length W1 of the width direction DW1 of the convex portion 50 is smaller than the minimum distance W2 of the pair of side guides 70A and 70B.

The convex portion 50 is supported by the upstream end of the feeding direction DF1 in the pressure plate 31 and is rotatable around the rotation axis X50. As shown in FIGS. 3 and 4, the convex portion 50 has a retracted position lying down along the support surface 3A and a protruding position where the upper end protrudes upward from the support surface 3A as shown in FIG. It is rotatable between.

The position of the convex portion 50 shown by the solid line in FIGS. 2 and 6 to 9 is a protruding position. The position of the convex portion 50 shown by the two-dot chain line in FIGS. 2 and 6 to 9 is the retracted position.

As shown in FIGS. 2 to 4, a convex portion urging member 59, which is a torsion coil spring, is provided between the pressure plate 31 and the convex portion 50. The convex portion urging member 59 urges the convex portion 50 toward the protruding position.

In this embodiment, the pressure plate 31 is provided with a holding means (not shown) capable of holding the convex portion 50 in the retracted position by a user's selection operation.

As shown in FIGS. 2 and 7, the convex portion 50 at the protruding position has an upper end located above the support surface 3A and supports the center of the feeding direction DF1 in the seat SH.

As shown in FIG. 7, even when the pressure plate 31 is rotated to the maximum rising position, the upper end of the convex portion 50 at the protruding position is located above the virtual straight line K1. That is, in the entire range in which the pressure plate 31 moves up and down, the upper end of the convex portion 50 is located above the virtual straight line K1 and supports the seat SH.

As shown in FIGS. 2 and 4, the feed tray accommodating portion 90 is provided with a first guide surface 9G. The first guide surface 9G is formed on the front surface of a protrusion that projects forward from the upper end side of the wall surface facing forward at the back of the feed tray accommodating portion 90. The first guide surface 9G is inclined backward while extending downward from the upper end thereof.

The first guide surface 9G abuts on the upper end of the convex portion 50 at the protruding position when the feed tray 3 rotates from the open position shown in FIG. 1 or the like to the closed position shown in FIG. 4, and the convex portion 50 protrudes. Guide from the position to the evacuation position.

When the feed tray 3 rotates from the closed position to the open position, the first guide surface 9G is separated from the upper end of the convex portion 50, so that the convex portion 50 is urged by the convex portion urging member 59 and is in the retracted position. It rotates to the protruding position from.

That is, the convex portion 50 can be rotated between the protruding position and the retracted position only by opening and closing the feeding tray 3.

<Action effect>
In the image forming apparatus 1 of the embodiment, as shown in FIG. 2, when the center of the feeding direction DF1 in the sheet SH supported by the support surface 3A is curled into an upward convex streak, the curl is caused by the convex portion 50. Supports the center of the feeding direction DF1 in the seat SH. As a result, it becomes difficult for the weight load F2 of the curled sheet SH to concentrate on the pressure plate 31 including the downstream end 3D of the feeding direction DF1 on the support surface 3A. Further, it is possible to suppress an increase in frictional resistance acting between the front end of the transmission lever 63 and the contact portion 31T of the pressure plate 31.

The same applies when the center of the feeding direction DF1 in the sheet SH supported by the support surface 3A is not curled into an upward ridge.

As a result, in this image forming apparatus 1, it is possible to suppress an increase in variation in the pressure contact load when the feeding roller 21 feeds the uppermost sheet SH supported by the support surface 3A.

Further, in this image forming apparatus 1, since the convex portion 50 is provided at a position upstream of the rotation axis X31 in the feeding direction DF1, even if the pressure plate 31 rises, the convex portion 50 and the feeding roller The seat SH is unlikely to be bent so as to meander between the seat SH and the uppermost seat SH, and the feeding resistance acting on the uppermost seat SH is unlikely to increase.

Therefore, in the image forming apparatus 1 of the embodiment, it is possible to suppress the feeding defect of the sheet SH.

Further, in the image forming apparatus 1, the convex portion 50 is provided on the pressure plate 31 at a position upstream of the rotation axis X31 in the feeding direction DF1. The self-weight load F2 of the sheet SH supported on the support surface 3A is large at the start of feeding when the number of loaded sheets is large, and becomes smaller as the feeding progresses and the number of loaded sheets decreases. Therefore, the support of the sheet SH by the convex portion 50 may be achieved at the initial stage of the start of feeding, and after that, the convex portion 50 does not increase the feeding resistance acting on the uppermost sheet SH. It is preferable that the support of the sheet SH by 50 is weakened. In this respect, according to the above configuration, as the number of loaded sheets decreases and the self-weight load F2 of the seat SH becomes smaller, that is, as the pressure plate 31 rises, the amount of protrusion of the convex portion 50 becomes smaller, and the convex portion 50 becomes the support surface 3A. Since it is retracted from the supported sheet SH, the feeding resistance acting on the uppermost sheet SH can be suitably suppressed.

Further, in this image forming apparatus 1, the convex portion 50 is supported by a retracted position laid down along the support surface 3A as shown by a two-dot chain line in FIG. 2 and an upper end as shown by a solid line in FIG. It is movable between a protruding position protruding above the surface 3A and a protruding position.

In this case, for example, depending on the size, thickness, curl state, etc. of the sheet SH, the user selects and operates a holding means (not shown) depending on whether the convex portion 50 is used or not, so that the convex portion 50 protrudes. You can select the position and the evacuation position. As a result, it is possible to avoid a state in which the convex portion 50 is always in the protruding position, and it is possible to prevent the convex portion 50 from affecting the sheet SH of uncurled thick paper or thin paper that is easily creases.

Further, in the image forming apparatus 1, the convex portion urging member 59 provided between the feeding tray 3 and the convex portion 50 urges the convex portion 50 toward the protruding position. With this configuration, as shown in FIG. 7, when the convex portion 50 supports the sheet SH supported by the support surface 3A, if the convex portion 50 is strongly pressed by the uncurled sheet SH, the convex portion is attached. The force member 59 reduces the amount of protrusion of the convex portion 50. On the other hand, as shown in FIG. 2, if the convex portion 50 is weakly pressed by the curled sheet SH, the convex portion urging member 59 increases the amount of protrusion of the convex portion 50. That is, the amount of protrusion of the convex portion 50 can be suitably changed according to the curled state of the sheet SH.

Further, as shown in FIG. 4, in the image forming apparatus 1, the first guide surface 9G provided in the feed tray accommodating portion 90 is in a protruding position when the feed tray 3 moves from the open position to the closed position. It abuts on the upper end of the convex portion 50 in the above and guides the convex portion 50 from the protruding position to the retracted position. With such a first guide surface 9G, it is not necessary to perform an operation of moving the convex portion 50 to the retracted position separately from the operation of moving the feed tray 3 to the closed position, so that the user's labor can be saved. ..

Further, in the image forming apparatus 1, as shown in FIG. 6, the upper end of the convex portion 50 is located above the virtual straight line K1 in a state where the pressure plate 31 is rotated to the maximum rising position. With such a specific configuration, the convex portion 50 can support the sheet SH with high certainty over the entire range in which the pressure plate 31 moves up and down.

Further, in the image forming apparatus 1, as shown in FIG. 3, the convex portion 50 is provided at the center of the width direction DW1 on the support surface 3A. With this configuration, the convex portion 50 can support each sheet SH with high certainty even when the sheet SHs of various sizes are supported by the support surface 3A.

Further, in the image forming apparatus 1, the length W1 of the width direction DW1 of the convex portion 50 is smaller than the minimum distance W2 of the pair of side guides 70A and 70B. With this configuration, it is possible to improve the degree of freedom in layout when the convex portion 50 is arranged between one side guide 70A and the other side guide 70B.

Although the present invention has been described above with reference to the examples, it is needless to say that the present invention is not limited to the above-mentioned embodiments and can be appropriately modified and applied without departing from the spirit of the present invention.

(Modification 1)
As shown in FIG. 8, in the first modification, the arrangement of the convex portion 50 according to the embodiment is changed, and the convex portion 50 is provided on the pressure plate 31 at a position where the convex portion 50 overlaps with the rotation axis X31 in the feeding direction DF1. Has been done. Further, in the first modification, the convex portion urging member 59 according to the embodiment is eliminated, and when the convex portion 50 is rotated to the protruding position by the user's manual operation, it is fixed to the protruding position and when it is rotated to the retracted position. It has been changed so that it is fixed at the evacuation position. Even in the image forming apparatus of the modified example 1 having such a configuration, it is possible to suppress the feeding defect of the sheet SH as in the image forming apparatus 1 of the embodiment.

(Modification 2)
As shown in FIG. 9, in the second modification, the arrangement of the convex portion 50 according to the embodiment is changed, and the convex portion 50 is located upstream of the rotation axis X31 in the feeding direction DF1, and the first sub tray 41 is used. It is provided in. That is, the convex portion 50 is provided at a position upstream of the pressure plate 31 in the feeding direction DF1. The convex portion urging member 59 according to the embodiment is provided between the first sub tray 41 and the convex portion 50 whose arrangement has been changed, and urges the convex portion 50 toward the protruding position. Even in the image forming apparatus of the modified example 2 having such a configuration, it is possible to suppress the feeding defect of the sheet SH as in the image forming apparatus 1 of the embodiment.

Further, in the second modification, the second guide surface 42G is provided on the second sub tray 42. The second guide surface 42G is moved to the protruding position by rotating the second sub tray 42 so as to overlap the first sub tray 41 when the first sub tray 41 and the second sub tray 42 move from the deployed position to the storage position. It abuts on the upper end of a certain convex portion 50 and guides the convex portion 50 from the protruding position to the retracted position. With such a second guide surface 42G, it is not necessary to perform an operation of moving the convex portion 50 to the evacuation position separately from the operation of moving the first sub tray 41 and the second sub tray 42 to the storage position, so that the user has trouble. Can be omitted.

The present invention also includes a configuration in which the convex portion 50 according to the embodiment is fixed at the protruding position and modified so as not to rotate.

The present invention can be used, for example, in an image forming apparatus, an image reading apparatus, a multifunction device, or the like.

1 ... Sheet feeding device (image forming device), SH ... Sheet DF1 ... Feeding direction, 21 ... Feeding roller, 3A ... Support surface 3U ... Upstream end of feeding direction on support surface 3D ... Feeding direction on support surface Downstream end 3 ... Feed tray, DW1 ... Support surface width direction, X31 ... Rotation axis 31 ... Pressure plate, 60 ... Biasing means, 50 ... Convex part, 59 ... Convex part urging member 9 ... Housing, 9S ... Side (front) of the housing
9G ... 1st guide surface, 30 ... Feed tray body 41, 42 ... Sub tray (41 ... 1st sub tray, 42 ... 2nd sub tray)
42G ... 2nd guide surface, K1 ... Virtual straight line 70A, 70B ... Pair of side guides, W1 ... Length in the width direction of the convex portion W2 ... When positioning the smallest size sheet that the support surface can support with respect to the center. Width distance between one side guide and the other side guide (minimum distance)
2 ... Image forming part

Claims (10)

A feeding roller that feeds the sheet in the feeding direction,
A feed tray having a support surface that is inclined downward from the upstream end to the downstream end in the feed direction to support the seat, and is rotatably supported around a rotation axis extending in the width direction of the support surface. The feed tray has a pressure plate that moves up and down below the feed roller, and the upper surface of the pressure plate constitutes a part of the support surface including the downstream end.
An urging means for urging the pressure plate toward the feeding roller, and
Provided with a convex portion provided on the feed tray, the upper end of which is located above the support surface to support the sheet.
The sheet feeding is characterized in that the convex portion is provided at a position overlapping the rotation axis in the feeding direction or at a position upstream of the rotation axis in the feeding direction. Feeding device. The sheet feeding device according to claim 1, wherein the convex portion is provided on the pressure plate at a position upstream of the rotation axis in the feeding direction. The sheet supply according to claim 1 or 2, wherein the convex portion is movable between a retracted position lying down along the support surface and a protruding position where the upper end projects upward from the support surface. Feeding device. The sheet feeding device according to claim 3, further comprising a convex portion urging member provided between the feeding tray and the convex portion to urge the convex portion toward the protruding position. With more housing
The feed tray is rotatably supported by the housing between an open position in which the seat can be supported by the support surface and a closed position closed along the side surface of the housing.
When the feed tray moves from the open position to the closed position, the housing abuts on the upper end of the convex portion at the protruding position, and the convex portion is moved from the protruding position to the retracted position. The sheet feeding device according to claim 4, wherein a first guide surface for guiding the user is provided. The feeding tray includes a feeding tray main body provided with the pressure plate and a feeding tray main body.
It is movably supported by the feed tray main body and is in the unfolded position between the unfolded position extending upstream of the feed tray main body in the feeding direction and the storage position overlapping the feed tray main body. It has a sub-tray that constitutes a part of the support surface including the upstream end in the state.
When the sub-tray moves from the unfolded position to the storage position, the sub-tray abuts on the upper end of the convex portion at the protruding position, and guides the convex portion from the protruding position to the retracted position. The sheet feeding device according to claim 4, wherein the second guide surface is provided. When a virtual straight line extending in the feeding direction and connecting the downstream end and the upstream end of the support surface is defined,
The sheet feeding device according to any one of claims 1 to 6, wherein the upper end of the convex portion is located above the virtual straight line in a state where the pressure plate is rotated to the maximum rising position. The sheet feeding device according to any one of claims 1 to 7, wherein the convex portion is provided at the center of the support surface in the width direction. Further provided with a pair of side guides provided on the feed tray that are accessible and separable from each other in the width direction and that position the sheet supported by the support surface with respect to the center reference in the width direction on the support surface.
The widthwise length of the convex portion is the widthwise distance between one side guide and the other side guide when the smallest size sheet that the support surface can support is positioned with respect to the center. The sheet feeding device according to claim 8, which is smaller than the above. The sheet feeding device according to any one of claims 1 to 9, further comprising an image forming unit for forming an image on a sheet fed by the feeding roller.

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