JP2004307200A - Sheet feeder, and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet feeder capable of reliably carrying a recording sheet with a tip of the recording sheet directed to a double-feed preventive member. <P>SOLUTION: The sheet feeder comprises a delivery roller 12 which delivers sheets stacked on a loading plate 11A and is abutted on the highest sheet out of the sheets stacked on the loading plate 11A, and a guide member 13 which is disposed in a vicinity of the sheet delivery side on the loading plate 11A and pressed and urged against the delivery roller 12. The guide member 13 having an inclined surface to constitute a wedge-shaped space capable of successively being converged from the loading plate 11A side along the sheet delivering direction. The inclined surface comprises a receiving part L1 having an angle from a lower side of the tip of the sheet below 90°, and a double-feed separation unit L2 continuous to the receiving part L1 to deliver the highest sheet out of the sheets delivered by the delivery roller 12 in a separated state from lower sheets. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sheet feeding apparatus and an image forming apparatus, and more particularly, to a configuration for preventing a feeding failure when feeding a recording sheet such as a transfer sheet stacked in a cassette.
[0002]
[Prior art]
2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, a facsimile machine, or a printing machine, an image formed in an image forming processing unit can be transferred to a recording sheet such as transfer paper to obtain a recording output.
[0003]
For example, in the case of a printer, a recording sheet on which an electrostatic latent image formed on a photoreceptor serving as a latent image carrier is processed into a visible image by a developing device, and the visible image is fed from a sheet feeding device. Is transcribed.
[0004]
The sheet feeding device is provided with a configuration for feeding out the recording sheets stacked and accommodated, and as an example, a mounting plate on which the recording sheets can be stacked and a topmost recording sheet on the mounting plate There is known a configuration including, as a main part, a feed roller that rotates in a direction in which the feed roller can be fed by contacting the feed roller (for example, Patent Document 1).
[0005]
On the other hand, it is necessary to prevent the double feeding by feeding only the uppermost one of the recording sheets stacked on the mounting plate at the time of feeding out. A gate member having a configuration capable of forming a gap through which only the uppermost recording sheet can pass is provided forward of the sheet feeding direction, and the gate member advances the recording sheet positioned below the uppermost recording sheet. (For example, Patent Document 1), or a separating pad that can be contacted with an angle so as to have a wedge-shaped convergence space with respect to the feeding roller, and a front of the separating pad. A guide member is provided for abutting the recording sheet against the separation pad. Configuration so as to pay out the roller feeding only the uppermost one of the recording sheet moving space (e.g., Patent Document 2).
[0006]
[Patent Document 1]
JP-A-8-91612 (paragraph "0012" column, FIG. 1)
[Patent Document 2]
JP-A-2002-226073 (paragraph "0018" column, FIG. 3)
[0007]
[Problems to be solved by the invention]
There are various types of recording sheets that are fed out of the mounting plate, such as those having burrs at the leading end due to cutting, and those that are reused such as backing paper. In particular, when a recording sheet having a bending habit (curl habit) is fed, if the leading end of the recording sheet fed from the mounting plate moves while hanging down, as shown in Patent Document 2 When it hits the separation pad, the movement is blocked, and a transport failure may occur. In other words, the recording sheet may not be able to advance due to the angle at which the leading end of the recording sheet strikes the separation pad. In particular, when the leading end of the recording sheet strikes from a direction perpendicular to the inclined surface of the separation pad, a component force for advancement may be obtained. The movement is hindered by the absence of the occurrence.
[0008]
One of the causes for preventing the movement of the recording sheet is that the leading end of the recording sheet hangs.
When the leading end of the recording sheet hangs, there is a frictional force generated between the recording sheets in addition to the above-described bending habit (curl habit), and the frictional force is affected by a difference in the surface state of the recording sheet. That is, in the case of reuse or the like, one surface of the recording sheet is an image surface unlike an unused recording sheet, and the image surface and the non-image surface are stacked facing each other. For this reason, the frictional force between the recording sheets at the time of feeding out the unused recording sheet and the frictional force between the recording sheets to be reused are different due to the difference in the surface condition, and the feeding roller The payout position when the amount of rotation is the same may be different. As a result, when the feeding amount is set based on the unused recording sheet, the frictional force between the recording sheets is larger than that of the unused recording sheet when the recording sheet to be reused is fed. As a result, the position of the leading end of the recording sheet is different. Specifically, a phenomenon in which the leading end hangs down without reaching the position where the leading end comes into contact with the friction pad or the separating pad is likely to occur.
[0009]
FIG. 8 is a view showing an ideal state of feeding a recording sheet. In FIG. 8, reference numeral A denotes a feeding roller, and reference numeral B denotes a part of which abuts on the peripheral surface of the feeding roller A. An inclined member corresponding to a discriminating pad that forms a wedge-shaped space by making the surface reaching the surface an inclined surface.
[0010]
The stacked recording sheets S are fed in a tangential direction at the contact position with the feeding roller A. FIG. 8 shows that the contact position of the feeding roller A with the recording sheet S is the contact position and the feeding roller. The line connecting the center of A (the line indicated by the reference numeral P1) is a position where a tangent line which coincides with the feeding direction of the recording sheet S in the horizontal direction is obtained. In this case, when the leading end of the recording sheet S abuts against the inclined surface B1 of the inclined member B, a component force using the inclined surface is generated, so that the recording sheet S can advance on the inclined surface B1. Note that, in FIG. 8, the case of performing the horizontal feeding is illustrated, but a direction other than the horizontal direction may be set as the feeding direction depending on the feeding mode.
[0011]
On the other hand, FIG. 9 shows a case where a bending habit (curl habit) has occurred in a recording sheet (for convenience, indicated by reference numeral S ′ as a recording sheet to be a lake after the drawing). The position of the feeding roller A that contacts the surface of the sheet S 'is different from P1 shown in FIG. That is, since the recording sheet S is fed out in the tangential direction generated on the peripheral surface of the feeding roller A that comes into contact with the surface, as shown in FIG. 8 will be different from the horizontal direction. For this reason, the feeding is performed at the position indicated by reference numeral P2 in FIG. 9, and as a result, if the feeding amount based on the rotation amount of the feeding roller A is the same as that shown in FIG. The leading end of the tip abuts on the inclined surface B1 of the inclined member B lower than the case shown in FIG.
[0012]
In FIG. 9, when the abutting angle corresponding to the angle between the lower surface of the leading end of the recording sheet S ′ and the inclined surface B1 of the inclined member B, which is indicated by α, is a right angle or more than the inclined surface B1, When the feeding is performed by the feeding roller A, the recording sheet S ′ is only pressed by the inclined surface B1 and does not advance toward the feeding roller A along the inclined surface B1. Will wake up.
[0013]
An example of a case where the abutting position of the inclined member B against the inclined surface B1 changes includes a difference in the specified state of the rear end in the feeding direction of the recording sheet. In other words, the rear end of the recording sheet in the feeding direction in a stacked state is defined by a rear end regulating member, a so-called end fence, and the like, and a change in the rear end position when a return phenomenon occurs during separation is prevented. However, if the position of the trailing end of the recording paper in the feeding direction is not uniform at the time of loading, the leading end in the feeding direction becomes uneven due to the constant amount of feeding by the feeding roller, and the inclined member is The abutment angle with respect to the inclined surface may be 90 degrees or more as described above. The cause of the hanging of the leading end of the recording sheet may be affected by gravity when the recording sheet does not reach the inclined surface of the inclined member and the bending rigidity of the recording sheet, that is, the so-called waist strength.
[0014]
SUMMARY OF THE INVENTION An object of the present invention is to provide a sheet feeding apparatus and an image forming apparatus having a configuration capable of reliably transporting the leading end of a recording sheet toward a double feeding prevention member in view of the above-described problems in the conventional sheet feeding apparatus. Is to do.
[0015]
[Means for Solving the Problems]
The invention according to claim 1 is a sheet feeding device for feeding out a sheet stacked on a mounting plate, and has a receiving surface for abutting a leading end of the sheet fed from the mounting plate. The receiving surface is characterized in that the receiving surface has a shape that does not generate a component force in the descending direction by using the moving force in the feeding direction of the sheet.
[0016]
According to a second aspect of the present invention, in addition to the first aspect, the receiving surface is formed of an inclined surface, and the inclined surface has an angle with the lower surface of the sheet leading end of less than 90 degrees. It is characterized in that it is configured to
[0017]
According to a third aspect of the present invention, there is provided a sheet feeding apparatus for feeding out a sheet stacked on a mounting plate, wherein the sheet feeding device abuts on the highest one of the sheets mounted on the mounting plate. A possible feeding roller, and a guide member disposed near the sheet feeding side of the placing plate and urged toward the feeding roller is provided, and the guide member extends along the sheet feeding direction. It has an inclined surface that forms a wedge-shaped space that can be sequentially converged from the mounting plate side, and the inclined surface has an angle of 90 degrees with the lower surface of the sheet leading end in order from the front side along the sheet feeding direction. A receiving portion having an angle of less than one degree, and a multi-feed separating portion for feeding out the uppermost one of the sheets fed out by the feed-out roller continuously from the receiving portion in a state of being separated from a sheet therebelow. Be prepared It is characterized in that.
[0018]
According to a fourth aspect of the present invention, in addition to the third aspect, the receiving portion and the double feed separating portion on the inclined surface have different angles, and the receiving portion utilizes the moving force of the sheet. Is set at an angle to move the sheet upward toward the double-feed separating section, and the double-feed separating section uses the moving force of the sheet to move the guide member by an amount that allows one sheet to pass. It is characterized in that the angle is set so as to generate a component force capable of forming a gap between the feeding roller and the feeding roller against the urging force against the pressing force.
[0019]
According to a fifth aspect of the present invention, in addition to the third or fourth aspect, the receiving portion has an angle between a lower surface of a leading end of the sheet in the feeding direction and a leading end of the sheet in the feeding direction of the sheet. It is characterized by being formed with an inclined surface smaller than the angle between the lower surface and the lower surface.
[0020]
According to a sixth aspect of the present invention, in addition to the third or fourth aspect, the receiving portion is provided integrally with a front side of the sheet feeding direction on a surface of the double feed separating portion. It is characterized by.
[0021]
According to a seventh aspect of the present invention, in addition to one of the third to sixth aspects, the receiving portion is formed as a continuous or intermittent portion in a direction perpendicular to the sheet feeding direction. It is provided on the front side of the sheet feeding section in the feeding direction of the sheet.
[0022]
According to an eighth aspect of the present invention, in addition to the third aspect of the present invention, a boundary portion where the receiving portion and the double feed separating portion intersect continuously with a surface having a curvature. It is characterized by having.
[0023]
According to a ninth aspect of the present invention, in addition to the one of the first to eighth aspects, the mounting plate on which the sheet can be stacked has a rear end of the sheet at a rear end in a feeding direction of the sheet. It is characterized in that the regulating member is provided in the vicinity.
[0024]
According to a tenth aspect of the present invention, the sheet feeding device according to the first aspect is used for an image forming apparatus.
[0025]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 shows an image forming apparatus to which a sheet feeding apparatus according to an embodiment of the present invention is applied. The image forming apparatus 1 shown in FIG. A document scanning unit S2 and a writing unit S3 are arranged above the processing unit S1, and a sheet feeding unit S4 is arranged below the processing unit S1.
The image forming processing unit S1 is provided with a drum-shaped photoconductor 2 as a latent image carrier, and performs image forming processing around the photoconductor 2 along the rotation direction of the photoconductor indicated by an arrow. , A developing device 4, a transfer device 5, and a cleaning device 6 are provided. The electrostatic latent image formed on the photoreceptor 2 is subjected to visible image processing by the developing device 4 and then transferred to a recording sheet S fed from a paper feeding unit S4.
[0026]
A conveyance device 7 using a belt and a fixing device 8 are disposed in the conveyance path of the recording sheet S after the transfer, and the fixing device 8 fixes the visible image carried on the recording sheet. Is discharged toward the paper discharge tray 9.
[0027]
The image forming apparatus 1 shown in FIG. 1 employs a configuration in which images are formed on both sides of a recording sheet, and includes a discharge path EP toward a discharge tray 9 as a conveyance path of the recording sheet having passed through the fixing device 8. After passing through the fixing device 8, after being once introduced into the reversing path, the recirculating path RP for re-feeding the recording sheet S in a state where the recording sheet S is reversed again toward the registration roller 10 provided in the sheet feeding unit S2. At the entrance to each of these transport paths, a switching member (not shown) such as a transport path switching claw is provided so that the transport direction can be selected.
[0028]
Although not described in detail, the document scanning unit S2 includes an optical system device for scanning a document placed on a document table. The writing unit S3 includes a laser light source (not described in detail). A scanning optical member using is provided.
[0029]
On the other hand, the sheet feeding unit S4 includes a loading plate 11A which is detachably provided in a cassette mounting unit provided in a housing forming the main body of the image forming apparatus 1 and which can stack the recording sheets S therein. A paper cassette 11, a delivery roller 12 that can be brought into contact with the uppermost one of the recording sheets S stacked on the placement plate 11A and that can rotate in the delivery direction, and a direction that comes into contact with the delivery roller 12. A guide member 13 that is pressed and urged and a feed roller 14 that feeds the recording sheet S fed from the mounting plate 11A toward the registration roller 10 are provided.
[0030]
As shown in FIG. 2, the above-mentioned feeding roller 12 and guide member 13 are provided in a cassette mounting portion in which the paper feed cassette 11 is detachably provided.
In FIG. 2, the cassette mounting portion includes a wall portion and a bottom portion that can surround the outer periphery of the sheet cassette 11 on all sides, and of those wall portions, a wall portion on the feeding side of the recording sheet S (for convenience, reference numeral 1A0). 2) is provided with a mounting portion 1A1 for the guide member 13 formed of a concave portion.
[0031]
The mounting portion 1A1 of the guide member 13 is provided at the center in the width direction corresponding to the direction perpendicular to the feeding direction of the recording sheet stacked on the mounting plate, and the mounting guide of the guide member 13 described later is provided on both sides of the concave portion. The rail 1A2 is formed so that the rib 13A provided on the guide member 13 side can be inserted.
[0032]
The guide member 13 is extended downward and has a pair of locking claws 13B at the distal end in the extension direction, and is urged toward the feeding roller 12 by an elastic body 14 such as a spring disposed on the same side as the locking claw 13B. It is supposed to be.
[0033]
As shown in FIG. 3, a wedge-shaped space that can be sequentially converged from the mounting plate side along the feeding direction of the recording sheet S (the direction of the arrow in the drawing) is provided above the guide member 13 corresponding to the base side of the locking claw 13B. An inclined surface constituting the ES is provided, and the inclined surface is formed with a receiving portion L1 and a multi-feed separating portion L2 in order from the front side in the feeding direction of the recording sheet.
[0034]
The surface of the receiving portion L1, that is, the receiving surface is configured to be inclined with an angle (β) at which the angle (α) with the lower surface of the leading end of the recording sheet is less than 90 degrees. It is a part that can be brought into contact. The angle (β) is a value based on the surface of the double feed separation unit L2. Therefore, when the leading end of the fed recording sheet S comes into contact with the surface of the receiving portion L1, that is, the receiving surface, the angle (α) between the lower surface of the leading end and the surface (receiving surface) of the receiving portion L1 is 90 degrees. 4B, an abutting state such as a case of a collision at 90 degrees as shown in FIG. 4B, or an angle of 90 ° or more as shown in FIG. Unlike the state in which a component force in the descending direction (indicated by FD for convenience) is generated as in the case of hitting the surface of α ′), as shown in FIG. (Indicated by FU for the sake of convenience), it is possible to move upward along the surface (receiving surface) of the receiving portion L1B, and reach the double feed separating portion L2 continuous with the receiving portion L1. it can.
[0035]
On the other hand, the double feed separation section L2 which is continuous with the receiving section L1 is a section for eliminating the double feed of the fed recording sheet, and the inclination angle (θ) of the surface thereof is based on the feeding direction of the recording sheet S. In this case, the angle between the receiving portion L1 and the lower surface of the leading end of the recording paper (the angle indicated by reference numeral α in FIG. 9) is set to be larger. As a result, the leading end of the recording sheet S abutting against the multi-feed separating portion L2 has a larger angle between the surface of the multi-feed separating portion L2 and the lower surface of the recording sheet leading end than in the receiving portion L1. This corresponds to the state shown in (C), where a component force for lowering the surface of the double feed separation portion L2 is generated and a component against the urging force of the elastic body 14 acting on the guide member 13 is generated. A force FS is generated. As a result, the guide member 13 can be separated from the feeding roller 12 by a gap that allows the uppermost recording sheet to pass.
[0036]
On the other hand, the second recording sheet located below the uppermost recording sheet is affected by the frictional load between the second recording sheet and the recording sheet located below the uppermost recording sheet. Force will be generated. Therefore, of the component forces from the feeding force, a component force in the direction of reducing the urging force of the elastic body acting on the guide member 13 is generated, but the elastic body generated by the feeding force of the uppermost recording sheet is generated. Since the force is smaller than the force for reducing the urging force, the force is not enough to push down the guide member 13 and pass the second recording sheet. As a result, only the uppermost recording sheet passes through the guide member 13, and the second and subsequent recording sheets in the double feed state are separated from the uppermost recording sheet.
[0037]
The position of the boundary portion LP where the receiving portion L1 and the multi-feed separating portion L2 intersect is set under the conditions shown in FIG.
In FIG. 5, reference numeral M0 denotes a feeding amount when an unused recording sheet is stacked (in a state indicated by a solid line in FIG. 5), and reference numeral M1 denotes a feeding amount when an unused recording sheet is stacked. The reference numeral M2 is a distance from an abutment position P1 with the roller 12 to the leading end of the recording sheet, and reference numeral M2 is the last unused recording sheet (corresponding to a two-dot chain line indicated by reference numeral S 'in FIG. 5). This is the distance from the contact position P1 with the feeding roller 12 (the response indicated by the two-dot chain line in FIG. 5) to the leading end of the recording sheet.
[0038]
The reason why the distance from the contact position P1 with the feeding roller 12 to the leading end of the recording sheet is different is due to the structure of the mounting plate, which is swingably supported inside the paper feed cassette 11, although not shown. The feeding side of the recording sheet is pushed up by an elastic body and is urged toward the feeding roller. For this reason, the swinging position of the mounting plate is different between the case where the number of stacked sheets is a certain number and the last sheet, whereby the distance from the contact position P1 with the feeding roller 12 to the leading end of the recording sheet is reduced. Change. Accordingly, when the rotation amount of the feeding roller 12 is defined so as to correspond to the feeding amount M0 of the recording sheet when the recording sheets are stacked, the feeding amount for the last one recording sheet is indicated by M0. Therefore, it does not reach the inclined surface of the guide member 13. As a result, the leading end of the last recording sheet hangs down due to gravity. In other words, in order to secure the same distance as the distance M1 from the contact position P1 to the leading end of the feeding roller 12 on the recording sheet at the time of stacking, the contact position of the feeding roller 12 with respect to the last one recording sheet. Must be shifted to the position indicated by the reference symbol P2, which is the same phenomenon as that shown in FIGS.
[0039]
In the present embodiment, as in the case where the last one recording sheet is fed, the surface of the receiving portion L1 is located at a position where the leading end of the recording sheet can be received without hanging down the inclined surface of the guide member 13 without reaching the inclined surface. The boundary part LP is positioned so as to be located. As a result, the recording sheet whose tip hangs down contacts the receiving portion L1 as described with reference to FIG. 4, regardless of whether the recording sheet is an unused recording sheet or a recording sheet having a curl. The tip is moved upward using the moving force at that time. In order for such an operation to function effectively, the distance (indicated by reference numeral M3 in FIG. 5) between the leading end of the recording sheet on the feeding side and the end of the receiving portion L1 of the guide member 13 should be as close as possible. It is desirable that the difference in the amount of sag due to the difference in bending stiffness of the recording sheet is reduced.
[0040]
The receiving portion L1 provided on the guide member 13 is provided so as to be superimposed on the surface of the double feeding separation portion L2, and its installation structure is such that the front surface of the double feeding separation portion L2 on the front side in the feeding direction of the recording sheet is provided. It is integrated.
[0041]
In addition, as an integrated structure, as shown in FIG. 6, a configuration in which the recording sheet is continuous in the width direction corresponding to a direction perpendicular to the feeding direction of the recording sheet or an intermittent portion as shown in FIG. The structure is provided as a corresponding rib structure. Such a configuration contributes to optimizing the frictional resistance generated on the recording sheet used.
[0042]
The boundary portion LP between the receiving portion L1 and the multi-feed separating portion L2 in the guide member 13 described above is not limited to the edge portion where each portion intersects, but is configured as a surface having a curvature and moves from the receiving portion L1. It is desirable that the leading edge of the recording sheet does not suddenly change its direction but changes its moving direction gently so as not to be stuck at the boundary portion LP, which is the crossing position, in order not to deteriorate the transportability.
[0043]
Since the present embodiment has the above configuration, if the leading edge of the recording sheet hangs down when the recording sheet stacked on the placing plate is fed out, the leading edge of the recording sheet hits the receiving portion L1 of the guide member 13. The contact causes a component force to move upward in the receiving portion L1 by utilizing the moving force of the recording sheet, whereby the leading end of the recording sheet moves upward along the receiving portion L1 to cause double feed separation. The section L2 can be reached.
As a result, as described with reference to FIG. 5, the stacking of unused recording sheets is performed regardless of whether the last unused recording sheet is fed out or when a bent recording sheet is fed out. As in the case where the number of sheets is large, the tangential direction of the feeding roller 12 at the contact position P1 is not obtained, and the feeding roller 12 is fed out in a direction different from the tangential direction and does not reach the multi-feed separating portion L2 of the guide member 13. Even if a feeding amount that causes the paper to hang down is obtained, the leading end can be continued and raised, and the separation function in the double feed separation unit L2 can be obtained.
[0044]
【The invention's effect】
According to the first aspect of the present invention, since the receiving surface against which the leading end of the sheet abuts does not generate a component force in the descending direction on the sheet, the receiving surface generated when the leading end of the sheet hangs down. It is possible to proceed along the receiving surface by eliminating the collision phenomenon with the tip of the head. Thus, it is possible to prevent the progress of the sheet from being hindered when the leading edge of the sheet abuts, thereby preventing a conveyance failure.
[0045]
According to the second aspect of the present invention, since the receiving surface has an angle of less than 90 degrees with the lower surface of the sheet leading end, the leading end of the sheet can be easily raised using the moving force of the sheet. can do. Thus, even when the leading end of the sheet abuts on the receiving surface, the sheet can be moved without being prevented from advancing, thereby preventing a conveyance failure.
[0046]
According to the third and fourth aspects of the present invention, the wedge-shaped space is disposed near the sheet feeding side of the mounting plate, is urged toward the feeding roller, and can sequentially converge from the mounting plate side in the sheet feeding direction. In the guide member having an inclined surface, a receiving portion having an angle of less than 90 degrees with respect to the lower surface of the sheet leading end, and a multi-feed separating portion continuously eliminating double feeding of the sheet are provided. By providing the sheet, the sheet tip can be moved toward the multi-feed separation unit without hanging down. As a result, the leading edge of the sheet abutting on the receiving portion can be reliably moved upward and moved toward the double-feed separating portion, so that double-feeding of the sheet can be reliably prevented, and movement of the sheet for double-feed separation is guaranteed. It is possible to do.
[0047]
According to the fifth aspect of the present invention, since the angle between the receiving portion and the lower surface of the sheet leading end with respect to the multi-feed separating surface is reduced, the ease with which the sheet leading end rises is increased, and the multi-feed separating portion is increased. Can be ensured.
[0048]
According to the sixth aspect of the present invention, since the receiving portion is integrated on the front side in the feeding direction on the surface of the double feed separation portion, it can be manufactured together with the double feed separation portion without special members. Thus, a multifunctional part can be obtained at low cost.
[0049]
According to the seventh aspect of the present invention, since the receiving portion is provided continuously or intermittently in a direction perpendicular to the feeding direction on the surface of the multi-feed separating portion, the frictional resistance between the sheet and the sheet is optimized and the receiving portion is formed. It is possible to select a mode for reducing the transport resistance.
[0050]
According to the eighth aspect of the present invention, since the boundary portion where the receiving portion and the multi-feed separating portion intersect is a surface having a curvature, the sheet moved along the receiving portion by suppressing the generation of the conveyance resistance is overlapped. It is possible to smoothly move toward the transport / separation unit.
[0051]
According to the ninth aspect of the present invention, since the rear end regulating member for regulating the rear end in the sheet feeding direction is provided on the rear end side of the mounting plate in the sheet feeding direction, the rear end of the sheet is regulated. Since the feeding amount of the sheet until reaching the receiving portion can be made uniform, and even when the trailing edge of the sheet is not aligned with the trailing edge regulating member, it is possible to set a state in which the leading edge of the sheet does not hang down by the receiving portion. It is possible to secure the movement toward the double feed separation unit.
[0052]
According to the tenth aspect of the present invention, since the leading end of the sheet is configured to be able to move along the receiving surface or the receiving portion without sagging, it is possible to eliminate a conveyance failure due to an impact phenomenon of the leading end of the sheet that occurs when the leading end is hung. Thus, processing such as double feed separation can be performed reliably.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus using a sheet feeding device according to an embodiment of the present invention.
FIG. 2 is a perspective view illustrating an installation structure of a guide member provided in a sheet feeding unit in the image forming apparatus illustrated in FIG.
FIG. 3 is a schematic diagram for explaining a main part configuration of a guide member used in the sheet feeding apparatus according to the embodiment of the present invention.
4A and 4B are diagrams for explaining a sheet feeding operation by the configuration of the main part shown in FIG. 3 and a sheet feeding operation when the configuration of the main part is different, and FIG. 4A is an embodiment of the present invention; (B) and (C) show the case different from the embodiment.
FIG. 5 is a view for explaining a configuration of a boundary portion between a receiving portion provided on the guide member shown in FIG. 3 and a multi-feed separating portion.
FIG. 6 is a perspective view showing one installation state of a receiving portion provided on the guide member shown in FIG. 3;
FIG. 7 is a perspective view showing another example of an installation state of a receiving portion provided on the guide member shown in FIG. 3;
FIG. 8 is a diagram illustrating a conventional example of a recording sheet feeding apparatus. D
FIG. 9 is a view for explaining a defect in the conventional structure shown in FIG. 8;
FIG. 10 is a view for explaining the operation of a deformable sheet in the conventional structure shown in FIG.
[Explanation of symbols]
1 Image forming apparatus
11 Paper cassette
11A Mounting plate
11B Rear end regulating member
12 Feeding roller
13 Guide member
L1 receiving part
L2 double feed separation unit

Claims (10)

A sheet feeding device for feeding out a sheet stacked on a mounting plate,
A receiving surface for abutting the leading end of the sheet fed from the mounting plate, wherein the receiving surface is configured to use a moving force in the feeding direction of the sheet so as not to generate a component force in a descending direction on the sheet; A sheet feeding device comprising: The sheet feeding device according to claim 1,
The sheet feeding device according to claim 1, wherein the receiving surface is formed by an inclined surface, and the inclined surface is formed to have an angle with the lower surface of the sheet leading end that is smaller than 90 degrees. A sheet feeding device for feeding out a sheet stacked on a mounting plate,
A feeding roller capable of contacting the uppermost sheet among the sheets placed on the placing plate,
A guide member disposed in the vicinity of the sheet feeding side of the mounting plate and pressed and urged toward the feeding roller,
The guide member has an inclined surface that forms a wedge-shaped space that can be sequentially converged from the mounting plate side along the sheet feeding direction, and the inclined surface is from the front side along the sheet feeding direction. In order, a receiving portion having an angle of less than 90 degrees with the lower surface of the sheet leading end, and the highest one of the sheets fed by the feeding roller continuously with the receiving portion is positioned below the receiving portion. And a multi-feed separation unit for feeding the sheet in a state where the sheet is separated from the sheet. The sheet feeding device according to claim 3,
The receiving portion and the double-feed separating portion on the inclined surface have different angles, and the receiving portion is set to an angle at which the sheet is moved upward toward the double-feed separating portion by using the moving force of the sheet. The multi-feed separating unit uses the moving force of the sheet to create a gap between the guide member and the feed-out roller in such a manner that the guide member is pressed against the guide member by an amount allowing passage of one sheet. A sheet feeding device, wherein the sheet feeding device is set at an angle capable of generating a component force that can be formed. The sheet feeding device according to claim 3 or 4,
The receiving portion is formed of an inclined surface in which an angle between the lower surface of the sheet in the feeding direction and the lower surface is smaller than an angle between the multi-feed separating portion and the lower surface of the sheet in the feeding direction. Sheet feeding device. The sheet feeding device according to claim 3 or 4,
The sheet feeding device, wherein the receiving portion is provided integrally with a front side of the sheet feeding direction on a surface of the double feed separating portion. The sheet feeding device according to any one of claims 3 to 6,
The sheet feeding device, wherein the receiving portion is provided as a continuous or intermittent portion in a direction perpendicular to the sheet feeding direction on the front side of the sheet feeding direction on the surface of the double feed separating portion. apparatus. The sheet feeding device according to any one of claims 3 to 7,
A sheet feeding device, wherein a boundary portion where the receiving portion intersects with the multi-feed separating portion is continuous on a surface having a curvature. The sheet feeding device according to any one of claims 1 to 8,
A sheet feeding device, wherein a sheet rear end regulating member is provided near a rear end of the sheet in the feeding direction of the sheet on which the sheet can be stacked. An image forming apparatus using the sheet feeding device according to claim 1.

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