JP2021098589A - Sheet loaded device and image formation apparatus - Google Patents

Abstract

To suppress generation of erroneous sheet feed by suppressing retreat of a sheet due to a kickback phenomenon with a simpler configuration than conventional ones.SOLUTION: A sheet loaded device 9 includes: a sheet loaded part 11 loaded with one or more sheets 19; a sheet push-up plate 21 supporting a front end part of the sheets 19 loaded on the sheet loaded part 11 and pushing up the front end part of the sheets 19; a paper feeding roller 31 abutting onto an upper end of the front end part of the sheets 19 loaded on the sheet loading part 11 and feeding the sheet 19; a separation roller 32 separating one sheet positioned at the uppermost sheet of a plurality of the sheets and feeding out the one sheet toward the downstream side when the plurality of sheets abut onto the paper feeding roller 31 and are fed by the paper feeding roller 31; and a projection part 22 provided on the top face of the sheet push-up plate 21 on the upstream side of a position at which the paper feeding roller 31 abuts onto the upper end of the front end part of a sheet 19.SELECTED DRAWING: Figure 6

Description

The present invention relates to a sheet loading device that loads sheets such as printing paper and supplies the sheets one by one to the image forming device, and an image forming device including the sheet loading device.

An image forming apparatus such as an MFP (Multifunction Peripherals) includes a sheet loading device that takes out sheets one by one from the sheets to be loaded and feeds them. Such a sheet loading device is provided on the side surface of the image forming device as, for example, a manual feed tray.

The sheet loading device includes a paper feeding mechanism that separates and feeds only one sheet located on the uppermost surface from a bundle of a plurality of sheets loaded on the sheet loading unit. This paper feed mechanism is composed of, for example, a paper feed roller and a separation roller. The paper feed roller abuts on the uppermost sheet at the tip position of the bundle of sheets and rotates in a predetermined direction to feed the sheet to the downstream side of the transport path. The separation roller is a roller that is paired with the paper feed roller, and is the first sheet on the uppermost surface when a plurality of sheets are fed out by the paper feed roller by contacting and acting on the surface of the paper feed roller. And the second and subsequent sheets are separated.

The separation roller is provided with an elastic member such as rubber on the outer peripheral surface, and a torque limiter is provided on the rotating shaft. When the second and subsequent sheets try to pass through the nip between the paper feed roller and the separation roller, the torque acting on the separation roller becomes less than a predetermined value, and the separation roller does not rotate and the second and subsequent sheets are downstream. Prevent it from progressing to the side. At this time, since stress is applied to the separation roller, elastic energy is accumulated. When the rear end of the first sheet on the uppermost surface passes through the nip between the paper feed roller and the separation roller, the rotation of the paper feed roller is stopped, so that the elastic energy stored in the separation roller is released. Will be done.

When the elastic energy stored in the separation roller is released, the separation roller returns from the elastically deformed or elastically displaced state to the original state. At this time, a force that pushes the sheet blocked by the separation roller back toward the upstream side in the paper feeding direction acts, and a phenomenon occurs in which the sheet retracts at the sheet loading portion. Hereinafter, this phenomenon is referred to as a "kickback phenomenon".

The kickback phenomenon occurs every time one sheet is fed. Kickback phenomenon The amount of retreat of the seat per time is small, but it changes depending on the loading state of the seat and the like. For example, if a kickback phenomenon with a relatively large amount of retreat occurs during continuous paper feeding, the tip of the sheet to be fed next will retreat to a position where it does not come into contact with the paper feed roller, and a paper feed error may occur. is there. The amount of retreat of the sheet due to the kickback phenomenon increases as the weight of the sheet becomes lighter, and increases as the sheet size becomes smaller for the same paper type. Therefore, there is a problem that a paper feeding error is likely to occur particularly when a small-sized sheet is continuously fed.

Conventionally, some methods for suppressing the kickback phenomenon and reducing paper feeding errors have been proposed (for example, Patent Documents 1, 2 and 3).

According to the prior art of Patent Document 1, when a seat is loaded on the seat loading portion, a rear end regulating plate is provided which projects upward from the seat loading surface and abuts on the rear end portion of the seat according to the seat size. , Suppresses the retreat of the seat due to the kickback phenomenon.

In the prior art of Patent Document 2, the sheet loading portion can be rotated so as to lift the rear end portion of the sheet, and each time the sheet is fed, the sheet loading portion is rotated to rotate the rear end portion of the sheet. By lifting the seat, the seat retracted by the kickback phenomenon can be returned to the tip side.

The prior art of Patent Document 3 is configured to provide a stepped portion in the seat loading portion and regulate the retreat of the rear end portion of the seat by the stepped portion.

JP-A-2015-174707 Japanese Unexamined Patent Publication No. 2003-276861 Japanese Unexamined Patent Publication No. 10-338363

However, in the prior art of Patent Document 1, in order to realize a configuration that can correspond to a plurality of sheet sizes, it is necessary to provide a rear end regulating plate at a position corresponding to each sheet size so that the rear end regulating plate can appear and disappear. There is a problem that the number increases.

Further, in the prior art of Patent Document 2, it is necessary to provide a drive mechanism for rotating the sheet loading portion, which complicates the structure and rotates the sheet loading portion each time one sheet is fed. Since it moves, there is a problem that a large noise is generated during continuous paper feeding.

Further, the prior art of Patent Document 3 can suppress the retreat of the sheet when the thickness of the sheet bundle is smaller than the stepped portion, but when the thickness of the sheet bundle is larger than the stepped portion, the upper layer portion. There is a problem that the seat recedes beyond the stepped portion.

Therefore, the present invention has been made to solve the above-mentioned problems, and the sheet loading is made so that the sheet can be suppressed from retreating due to the kickback phenomenon and the occurrence of paper feed error can be reduced by a simpler configuration than the conventional one. It is an object of the present invention to provide an apparatus and an image forming apparatus.

In order to achieve the above object, the invention according to claim 1 is a sheet loading device, which supports a sheet loading portion for loading a sheet and a tip portion of a sheet loaded on the sheet loading portion, and supports the tip of the sheet. A sheet push-up plate that pushes up a portion, a paper feed roller that abuts on the upper end of the tip portion of the sheet loaded on the sheet loading portion to feed the sheet, and a plurality of paper feed rollers that abut on the paper feed roller and abut on the paper feed roller. When a sheet is fed, a separation roller that separates one sheet located at the top of the plurality of sheets and sends it to the downstream side, and the paper feed roller at the upper end of the tip of the sheet. The configuration is characterized in that a protrusion provided on the upper surface of the sheet push-up plate is provided on the upstream side of the position where the sheet is brought into contact with the sheet.

The invention according to claim 2 is the seat loading device according to claim 1, wherein the protrusion forms a bent portion at the tip end portion of the seat.

The invention according to claim 3 is characterized in that, in the sheet loading device according to claim 1 or 2, the protrusion is provided on the upstream side of a position where the paper feed roller abuts on the upper end of the tip end portion of the sheet. It is a composition.

The invention according to claim 4 is characterized in that, in the sheet loading device according to any one of claims 1 to 3, the width dimension of the protrusion in the direction orthogonal to the paper feeding direction is smaller than the width of the sheet. Is.

The invention according to claim 5 is the sheet loading device according to claim 4, wherein the width dimension of the protrusion is 30% or less of the width dimension of the minimum size sheet.

The invention according to claim 6 is characterized in that, in the sheet loading device according to any one of claims 1 to 5, the protrusion is provided at a position substantially center of the width of the sheet on the upper surface of the sheet push-up plate. It is a composition.

The invention according to claim 7 is the sheet loading device according to any one of claims 1 to 6, wherein the protrusion has a height of 0.7 mm or more from the upper surface of the sheet pushing plate. Is.

The invention according to claim 8 is the sheet loading device according to any one of claims 1 to 7, wherein the protrusion has an inclined portion whose height gradually increases from the upstream side to the downstream side in the paper feeding direction. It is a configuration characterized by.

The invention according to claim 9 is provided in the sheet loading device according to any one of claims 1 to 8 so as to be able to move up and down at a position above the protrusion, and lower when the sheet is fed by the paper feed roller. The configuration is characterized in that a roller member that comes into contact with the sheet loaded on the protrusion is further provided.

The invention according to claim 10 is the sheet loading device according to claim 9, wherein the roller member has a width dimension in a direction orthogonal to the paper feeding direction, which is larger than the width of the protrusion.

The invention according to claim 11 is the sheet loading device according to claim 9 or 10, wherein a recess corresponding to the outer shape of the roller member is formed on the upper surface of the protrusion.

The invention according to claim 12 is an image forming apparatus, which comprises the sheet loading apparatus according to any one of claims 1 to 11.

The invention according to claim 13 is the image forming apparatus according to claim 12, wherein the sheet loading device is provided as a manual feed tray.

According to the present invention, a protrusion provided on the upper surface of the seat push-up plate bends the seat to form a bend. The bent portion of the seat formed by the protrusions acts as a resistance and suppresses the seat from retreating due to the kickback phenomenon. Therefore, it is possible to suppress the retreat of the sheet due to the kickback phenomenon and reduce the occurrence of paper feed errors with a simpler configuration than the conventional one.

It is a figure which shows one configuration example of an image forming apparatus. It is a perspective view which shows the sheet loading apparatus in an enlarged manner. It is sectional drawing which shows the structure of the sheet loading apparatus. It is a figure which shows the YZ plane of a sheet push-up plate enlarged. It is a figure which shows the XZ plane of a sheet push-up plate enlarged. It is a figure which shows the YZ plane of the sheet loading apparatus when a sheet feeding operation is performed. It is a figure which enlarges and shows the YZ plane of the region near the sheet push-up plate in the state where the paper feed operation is possible. It is a figure which enlarges and shows the XZ plane of the region near the protrusion with the sheet loaded. It is a figure which illustrates the sheet loading device at the time of loading the sheet having a different width dimension. It is a graph which showed the relationship between the sheet retreat amount of the same paper type but different size, and the height dimension of a protrusion. It is a figure which shows another example regarding the top surface shape of a protrusion. It is a figure which shows the modification of the concave part shown in FIG.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. In the embodiments described below, elements that are common to each other are designated by the same reference numerals, and duplicate description thereof will be omitted.

FIG. 1 is a diagram showing a configuration example of an image forming apparatus 1 according to an embodiment of the present invention. The XYZ three-dimensional coordinate system shown in FIG. 1 is a coordinate system in which the XY plane is a horizontal plane and the Z-axis direction is a vertical direction, and is a coordinate system common to the coordinate systems shown in other figures. The image forming apparatus 1 shown in FIG. 1 is configured by, for example, an MFP (Multifunction Peripherals) and has a plurality of functions such as a scanning function, a printing function, and a copying function.

The image forming apparatus 1 has an image forming unit 2 in the center of the apparatus main body 1a, and has a plurality of paper feed cassettes 3 in the lower part of the image forming unit 2. Each of the plurality of paper cassettes 3 accommodates a bundle of sheets such as printing paper. Each paper cassette 3 feeds one sheet to the image forming unit 2 when a print job based on the print function or the copy function is executed in the image forming apparatus 1. The image forming unit 2 forms an image on the sheets fed from each paper cassette 3 based on the image data to be printed, and outputs the printed sheet to the upper sheet discharging unit 4.

Further, the image forming apparatus 1 has a document reading unit 5 above the apparatus main body 1a, and an automatic document transporting unit (ADF) 6 that automatically transports documents above the document scanning unit 5. The automatic document transfer unit 6 is provided with a document placing unit 7 for loading a document to be read by the document reading unit 5. The automatic document transporting unit 6 takes out the documents set in the document placing section 7 one by one and automatically transports the documents to a predetermined document reading position by the document reading unit 5. The document scanning unit 5 optically reads the image of the document when the document transported by the automatic document transport unit 6 passes through the document scanning position, and generates image data.

Further, the image forming apparatus 1 has an operation panel 8 on the upper front side of the apparatus main body 1a. The operation panel 8 is a user interface for a user who intends to use the image forming apparatus 1, and has a display unit composed of a color liquid crystal display or the like and an operation unit composed of touch panel keys or the like. .. The operation panel 8 displays various operation screens that can be operated by the user, and accepts operations by the user.

Further, the image forming apparatus 1 is provided with a sheet loading device 9 on the side surface side of the apparatus main body 1a. The sheet loading device 9 is provided as, for example, a manual feed tray 10 for setting a sheet for printing that is not accommodated in a plurality of paper cassettes 3. The sheet loading device 9 can be rotated around the horizontal axis of the side surface of the device main body 1a, and can be accommodated in the same surface as the side surface of the device main body 1a when not used by the user. For example, when printing is performed using a sheet that is not housed in the paper cassette 3, the user rotates the sheet loading device 9 around the horizontal axis to rotate the sheet loading device 9 around the horizontal axis, so that the device main body 1a can be printed as shown in FIG. The sheet loading device 9 is opened on the side surface, and the sheet can be fed by using the sheet loading device 9.

Similar to the paper feed cassette 3, the sheet loading device 9 can feed sheets one by one to the image forming unit 2 when a print job based on the print function or the copy function is executed in the image forming apparatus 1. it can. In this case, the image forming unit 2 forms an image on the sheet fed from the sheet loading device 9 based on the image data to be printed, and discharges the printed sheet to the upper sheet discharging unit 4.

FIG. 2 is an enlarged perspective view of the seat loading device 9. The sheet loading device 9 includes a sheet loading unit 11 that can rotate around a horizontal axis on the side surface of the device main body 1a. The sheet loading device 9 loads a sheet on the upper surface of the sheet loading unit 11. The seat loading portion 11 is provided with a pair of regulating plates 13 that regulate the left and right side surfaces of the seat bundle on the upper surface thereof. The pair of regulation plates 13 can be moved along the guide groove 14 formed in the X direction on the upper surface of the seat loading portion 11, and are positioned according to the size (width dimension) of the seat loaded on the seat loading portion 11. Can be set to. Further, the pair of regulation plates 13 are interlocked with each other so as to be separated from each other or close to each other with reference to the central position of the guide groove 14, and the sheet loaded on the seat loading portion 11 is arranged at the central position of the seat loading portion 11. The positions of the left and right sides of the seat are regulated so as to.

Further, the sheet loading unit 11 has a plurality of size detection sensors 15 and 16 for automatically detecting the size of the sheet. These size detection sensors 15 and 16 can appear and disappear on the upper surface of the seat loading portion 11, and immerse inside the seat loading portion 11 depending on the weight of the loaded seat. Then, the size of the seat can be detected according to the position and number of the sensors embedded in the seat loading portion 11 among the plurality of size detection sensors 15 and 16.

Further, the seat loading device 9 has a seat insertion port 20 for inserting the tip of the sheet into the back side (inside of the device main body 1a) of the seat loading unit 11. The seat loading device 9 includes a seat pushing plate 21 and an auxiliary roller 40 inside the seat insertion port 20. The seat push-up plate 21 is arranged as the bottom surface of the seat insertion port 20 and supports the tip end portion of the seat loaded on the seat loading portion 11. That is, the seat push-up plate 21 supports the lower surface of the tip of the sheet to be inserted into the seat insertion port 20. A protrusion 22 protruding from the upper surface of the seat push-up plate 21 is provided at the center of the seat push-up plate 21 in the width direction (X direction). The auxiliary roller 40 is a roller member provided above the protrusion 22 and assists the pickup operation when the sheet is fed. In this embodiment, a configuration example in which the auxiliary roller 40 is provided above the protrusion 22 will be described, but the seat loading device 9 may not be provided with the auxiliary roller 40. The user can set the sheet in the sheet loading device 9 by inserting the tip of the sheet into such a sheet insertion port 20.

FIG. 3 is a cross-sectional view showing the structure of the seat loading device 9. The sheet loading device 9 includes a paper feed roller 31 and a separation roller 32 inside the device main body 1a, in addition to the sheet push-up plate 21 and the auxiliary roller 40 described above.

The seat push-up plate 21 is rotatable around a rotation shaft 23 in the horizontal direction (X direction) provided near the side surface of the device main body 1a. A drive mechanism 24 for raising and lowering the seat push-up plate 21 is provided on the lower surface side of the seat push-up plate 21, and when the drive mechanism 24 is driven, the seat push-up plate 21 rotates around the rotation shaft 23, and the seat is seated. The tip of the sheet loaded on the loading device 9 can be pushed up. For example, when a print job specified by the user to use a sheet loaded on the sheet loading device 9 is executed, the drive mechanism 24 pushes up the sheet pushing plate 21 to push up the sheet loaded on the sheet loading device 9. Is ready to be fed.

The paper feed roller 31 is provided at a position above the tip (end in the Y direction) of the sheet push-up plate 21 and comes into contact with the upper surface of the tip of the sheet pushed up by the sheet push-up plate 21. For example, the paper feed roller 31 abuts a portion of the outer peripheral surface of the cylindrical roller held in the horizontal direction near the lowest point on the upper surface of the tip of the sheet. Then, the paper feed roller 31 is rotationally driven in a predetermined direction (clockwise direction) to feed the sheet toward the transport path 33 on the downstream side. When a sheet bundle composed of a plurality of sheets is set in the sheet loading device 9, when the paper feeding operation is performed by the paper feeding roller 31, not only one sheet on the uppermost surface of the sheet bundle but also two sheets are used. Sheets after the eyes may also be sent downstream at the same time.

The separation roller 32 is a roller paired with the paper feed roller 31, and comes into contact with the surface of the paper feed roller 31 at a position rotated by a predetermined angle in a predetermined direction (clockwise direction) from the lowest point of the paper feed roller 31. There is. The separation roller 32 is provided with an elastic member such as rubber on the outer peripheral surface, and the elastic member is in contact with the surface of the paper feed roller 31. The separation roller 32 is configured to be driven to rotate as the paper feed roller 31 rotates. However, a torque limiter is provided on the rotation shaft of the separation roller 32, and when the torque acting on the separation roller 32 is equal to or less than a predetermined value, the torque limiter does not rotate, and the torque acting on the separation roller 32 exceeds the predetermined value. It rotates according to the case. The separation roller 32 separates the first sheet and the second and subsequent sheets on the uppermost surface when a plurality of sheets fed by the paper feed roller 31 are sent out, and the second and subsequent sheets are separated. The sheet is restricted from being sent out to the transport path 33 on the downstream side. When the second and subsequent sheets try to pass through the nip portion between the paper feed roller and the separation roller, the separation roller 32 imparts resistance due to the torque limiter to the second and subsequent sheets, and the second and subsequent sheets are released. Prevents it from passing through the nip. As a result, only the first sheet on the uppermost surface can be supplied to the transport path 33 on the downstream side.

The auxiliary roller 40 is arranged on the upstream side (−Y direction side) of the paper feed roller 31. An elastic member is provided on the outer peripheral surface of the auxiliary roller 40, and the frictional force of the elastic member assists the paper feeding operation of the sheet. The shaft portion of the auxiliary roller 40 is supported by an arm member, and the arm member can rotate to move up and down in the vertical direction. For example, the auxiliary roller 40 is lowered when the paper feed roller 31 feeds paper, and is in contact with the upper surface of the sheet. The auxiliary roller 40 assists the paper feeding operation by the paper feeding roller 31 so that a sheet requiring a relatively large feeding force such as thick paper is properly fed. Therefore, the auxiliary roller 40 is rotationally driven in a predetermined direction (clockwise direction) at the same time as the paper feed roller 31 by the same drive source as the paper feed roller 31 or another drive source.

FIG. 4 is an enlarged view showing the YZ plane of the seat push-up plate 21. As described above, the protrusion 22 is provided on the upper surface of the seat push-up plate 21. As shown in FIG. 3, the protrusion 22 is configured so that the height gradually increases in the paper feeding direction (Y direction). That is, the protrusion 22 has an inclined portion 22a whose height gradually increases from the upstream side (−Y direction side) to the downstream side (+ Y direction side) in the paper feeding direction. Further, the protrusion 22 has a step portion 22b at the tip on the upstream side. The step portion 22b is provided on the downstream side of the tip portion of the seat push-up plate 21. Specifically, the tip of the protrusion 22 is provided on the upstream side of the lowest point of the paper feed roller 31 as shown in FIG.

FIG. 5 is an enlarged view showing the XZ plane of the seat push-up plate 21. The sheet push-up plate 21 is formed so that the width dimension in the X direction is about the same as the width dimension of the sheet insertion port 20. As shown in FIG. 5, the protrusion 22 is provided at the center position of the seat push-up plate 21 on the upper surface of the seat push-up plate 21. On the other hand, the sheet loaded on the sheet loading device 9 is loaded so that the center in the width direction (X direction) of the sheet coincides with the center of the sheet pushing plate 21 regardless of the size of the sheet. Therefore, the protrusion 22 is provided at a substantially central position of the width of the seat on the front surface of the seat push-up plate 21. The protrusion 22 projects upward from the upper surface of the seat push-up plate 21 at a predetermined height H, and the width dimension in the X direction is provided as L1.

An auxiliary roller 40 is provided above the protrusion 22. The auxiliary roller 40 is also provided at the center position in the width direction of the sheet to be loaded on the sheet loading device 9. The width dimension of the auxiliary roller 40 is L2. In the sheet loading device 9 of the present embodiment, the relationship between the width dimension L1 of the protrusion 22 and the width dimension L2 of the auxiliary roller 40 is L1 <L2.

Next, a state in which the sheet is loaded on the sheet loading device 9 will be described. FIG. 6 is a diagram showing a YZ plane of the sheet loading device 9 when the sheet 19 is loaded and the paper feeding operation is performed. The tip of the sheet 19 to be loaded on the sheet loading unit 11 of the sheet loading device 9 is inserted into the sheet insertion port 20. As a result, the tip of the seat 19 is set in a state where it has entered the tip position of the seat push-up plate 21. Since the upstream side of the protrusion 22 is a gently inclined portion 22a, when the seat 19 is inserted into the seat insertion port 20, the protrusion 22 does not become an obstacle and the seat 19 can be smoothly inserted. Can be done. That is, the inclined portion 22a of the protruding portion 22 exerts an effect of improving workability when the user loads the seat 19 on the seat loading device 9. Then, when the user instructs the start of execution of the print job, as shown in FIG. 6, the sheet pushing plate 21 pushes up the tip of the sheet 19, and the upper surface of the tip of the sheet 19 comes into contact with the paper feed roller 31. It becomes. At this time, the auxiliary roller 40 is lowered, and the outer peripheral surface of the auxiliary roller 40 comes into contact with the upper surface of the sheet 19 at a position above the protrusion 22. When the paper feed roller 31 and the auxiliary roller 40 come into contact with the upper surface of the sheet 19 in this way, the sheet loading device 9 can perform the paper feed operation.

FIG. 7 is an enlarged view showing the YZ plane in the vicinity region of the sheet pushing plate 21 in a state where the paper feeding operation is possible. As shown in FIG. 7, the tip portion of the seat 19 supported by the seat push-up plate 21 causes a bent portion 19a on the downstream side of the protrusion portion 22. The bent portion 19a is formed at a position near the upstream side of a position where the paper feed roller 31 comes into contact with the paper feed roller 31. By forming a bent portion 19a in which the sheet 19 is bent at a position near the upstream side of the tip portion of the sheet 19 where it comes into contact with the paper feed roller 31, it is possible to suppress the retreat of the sheet 19 due to the kickback phenomenon.

When the paper feed roller 31 starts the paper feed operation and conveys a plurality of sheets to the nip portion between the paper feed roller 31 and the separation roller 32, as described above, the second and subsequent sheets of the separation roller 32 are on the downstream side. It is prevented from being transported to the transport path 33 of. At this time, the separation roller 32 is in a state of elastic deformation or elastic displacement, and is in a state of accumulating elastic energy. When the rear end of the first sheet on the uppermost surface passes through the nip between the paper feed roller and the separation roller, the rotation of the paper feed roller is stopped, so that the elastic energy stored in the separation roller is released. Then, a kickback phenomenon occurs in which the seat 19 is retracted.

On the other hand, the sheet 19 has a bent portion 19a formed on the rear side (upstream side in the paper feeding direction) of the point on which the force due to the kickback phenomenon acts, and the tip portion of the sheet 19 must be retracted in order to retract. Since it is necessary to overcome the inclination caused by the bent portion 19a, the tip portion of the seat 19 is less likely to retract as compared with the case where the tip portion of the seat 19 is placed in a flat state. That is, the bent portion 19a at the tip of the seat 19 formed by the protrusion 22 functions as a kind of resistance that prevents the seat 19 from retracting. As described above, when the seat loading device 9 is provided with the protruding portion 22 protruding from the upper surface of the seat pushing plate 21 to form a bent portion 19a at the tip end portion of the seat 19, and the seat 19 retracts the bent portion 19a. It is possible to reduce the amount of retreat of the sheet 19 when a kickback phenomenon occurs, and it is possible to prevent the occurrence of a paper feed error during continuous paper feed.

Further, since the protrusion 22 is formed on the upper surface of the seat push-up plate 21, the bent portion 19a of the seat 19 can be formed at a position near the point where the force due to the kickback phenomenon acts. Therefore, there is an advantage that it is possible to prevent the phenomenon that the tip portion of the seat 19 that retracts when the kickback phenomenon occurs bends the seat 19 with the bent portion 19a.

On the other hand, for example, when the protrusion 22 is formed on the upper surface of the seat loading portion 11, the flat portion of the seat 19 is widely formed between the tip portion of the seat 19 and the bent portion 19a. In such a case, when a force for retracting the tip of the seat 19 acts due to the kickback phenomenon, the seat 19 bends the flat portion to retract the tip of the seat 19, and then supplies the sheet 19. Paper mistakes may occur. In order to prevent the tip portion of the seat 19 from retracting due to such bending of the seat 19, the protrusion 22 is formed on the upper surface of the seat push-up plate 21 as described above, and the bent portion 19a is kicked back. It is preferable that the force can be formed in the vicinity of the point on which the force is applied.

FIG. 8 is an enlarged view showing the XZ plane of the region near the protrusion 22 in the state where the seat 19 is loaded. As shown in FIG. 8A, the seat loading device 9 of the present embodiment is assisted because the width dimension L1 of the protrusion 22 formed on the upper surface of the seat pushing plate 21 is smaller than the width dimension L2 of the auxiliary roller 40. When the roller 40 descends and presses the sheet 19 against the protrusions 22, the seats 19 are curved so as to hang down from the left and right ends of the protrusions 22 to form bent portions 19b at both ends of the protrusions 22. The bent portion 19b imparts further resistance to the seat 19 when the seat 19 retracts, similarly to the bent portion 19a formed along the Y direction described above.

On the other hand, when the width dimension L1 of the protrusion 22 is larger than the width dimension L2 of the auxiliary roller 40, the tendency of the sheet 19 to hang down becomes small. FIG. 8B shows a case where the width dimension L1 of the protrusion 22 is larger than the width dimension L2 of the auxiliary roller 40. In this case, when the auxiliary roller 40 is lowered and the sheet 19 is pressed against the protrusion 22, a phenomenon occurs in which the sheet 19 is lifted at both left and right ends of the auxiliary roller 40 as shown in FIG. 8 (b). Therefore, the bent portion 19b as shown in FIG. 8A is unlikely to occur, and it may not be possible to impart effective resistance when the seat 19 retracts. Therefore, in the sheet loading device 9 of the present embodiment, as shown in FIG. 8A, the width dimension L1 of the protrusion 22 is made smaller than the width dimension L2 of the auxiliary roller 40, so that the seat 19 has a bent portion 19b. Is generated so that effective resistance can be imparted to the seat 19 when the seat 19 retracts.

Such a bent portion 19b further increases the resistance due to the bent portion 19a (see FIG. 7) formed at the tip of the protrusion 22 along the Y direction. Therefore, by forming the bent portions 19b on which the seat 19 hangs down at both the left and right ends of the protruding portion 22, it is possible to further prevent the seat 19 from retreating.

Next, the width dimension of the protrusion 22 and the width dimension of the sheet 19 will be described. FIG. 9 is a diagram illustrating a seat loading device 9 when seats 19 having different width dimensions are loaded. FIG. 9A shows a case where the sheet size is relatively large and the width dimension L3 of the sheet 19 is large. As shown in FIG. 9A, when the width dimension L3 of the sheet 19 is large, the ratio of the width dimension L1 of the protrusion 22 to the width dimension L3 of the sheet 19 is small. In this case, the sheet 19 tends to hang down from the left and right ends of the protrusion 22. Therefore, the above-mentioned bent portions 19b are likely to be formed on the left and right ends of the protruding portion 22, and when the seat 19 retracts due to the kickback phenomenon, resistance can be applied to the seat 19.

On the other hand, FIG. 9B shows a case where the sheet size is relatively small and the width dimension L3 of the sheet 19 is small. As shown in FIG. 9A, when the width dimension L3 of the sheet 19 is large, the ratio of the width dimension L1 of the protrusion 22 to the width dimension L3 of the sheet 19 becomes large. In this case, since the seat 19 is less likely to hang down from the left and right ends of the protruding portion 22, the bending amount of the bent portion 19b is reduced. Therefore, when the seat 19 retracts due to the kickback phenomenon, the resistance that can be applied to the seat 19 becomes small.

That is, as the ratio of the width dimension L1 of the protrusion 22 to the width dimension L3 of the seat 19 increases, the bending amount of the bent portion 19b becomes smaller, so that the resistance force when the seat 19 retracts becomes weaker. For example, when the width dimension L1 of the protrusion 22 is 50 mm, when the A4 size sheet 19 is loaded on the seat loading portion 11 in the SEF (Short Edge Feed) mode, the width dimension of the protrusion 22 with respect to the width dimension L3 of the sheet 19 The ratio R of L1 is R = L1 / L3 = 50/297≈0.17. Further, assuming that the minimum size of the sheet 19 that can be fed in the sheet loading device 9 is the A6 size SEF (Short Edge Feed) mode, the ratio R in that case is R = 50/105 ≈ 0.48. .. Since this ratio R represents the resistance force when the seat 19 retracts, it is preferably 30% or less. That is, the width dimension L1 of the protrusion 22 is preferably 30% or less of the width dimension of the minimum size sheet 19 fed by the sheet loading device 9. Assuming that the minimum size of the sheet 19 that can be fed in the sheet loading device 9 is the A6 size SEF (Short Edge Feed) mode as described above, the width dimension L1 of the protrusion 22 may be about 30 mm or less. preferable. As a result, among the sheet sizes that can be fed by the sheet loading device 9, no matter what size of the sheet 19 is fed, the sheet 19 hangs down from the left and right ends of the protrusion 22 and is effectively bent. It is possible to form the portion 19b, and it becomes possible to satisfactorily prevent the seat 19 from retreating when a kickback phenomenon occurs.

Next, the height dimension H (see FIG. 5) of the protrusion 22 will be described. The amount of retreat of the seat 19 when the kickback phenomenon occurs decreases as the weight of the seat increases. That is, for the same paper type, the larger the size of the sheet 19, the smaller the amount of retreat. FIG. 10 is a graph showing the relationship between the amount of sheet retreat of the same paper type and different sizes and the height dimension H of the protrusion 22. The basis weight of the sheet 19 shown in FIG. 10 is 68 g / m2.

For example, when the protrusion 22 is not formed on the seat push-up plate 21 (black circles in the figure), when the kickback phenomenon occurs, the A4 size sheet 19 retracts by 0.7 mm, and the A5 size sheet 19 moves 1. The A6 size sheet 19 retracts by 0 mm and retracts by 1.5 mm. If the sheet 19 is retracted by 1.0 mm or more in one kickback phenomenon, a paper feed error is likely to occur in the subsequent sheet 19. Therefore, if the protrusion 22 is not formed, there is a possibility that a paper feeding error may occur in the A5 size and A6 size sheets 19 during continuous paper feeding.

Further, when the protrusion 22 is formed on the seat pushing plate 21 and the height dimension H from the upper surface of the seat pushing plate 21 is 0.4 mm (double circle in the figure), when the kickback phenomenon occurs, The A4 size sheet 19 retracts 0.5 mm, the A5 size sheet 19 retracts 0.8 mm, and the A6 size sheet 19 retracts 1.2 mm. Therefore, when the height dimension H of the protrusion 22 is 0.4 mm, there is a possibility that a paper feeding error may occur in the A6 size sheet 19 during continuous paper feeding.

On the other hand, when the protrusion 22 is formed on the seat push-up plate 21 and the height dimension H from the upper surface of the seat push-up plate 21 is 0.7 mm (square in the figure), when the kickback phenomenon occurs, The A4 size sheet 19 retracts 0.3 mm, the A5 size sheet 19 retracts 0.4 mm, and the A6 size sheet 19 retracts 0.9 mm. Therefore, when the height dimension H of the protrusion 22 is 0.7 mm, there is no possibility that a paper feeding error will occur during continuous paper feeding. Similarly, when the height dimension H of the protrusion 22 is 1.0 mm (triangle in the figure) or when the height dimension H of the protrusion 22 is 1.5 mm, the paper is fed during continuous paper feeding. There is no possibility of mistakes.

According to the above verification result, if the height dimension H from the upper surface of the seat pushing plate 21 is 0.7 mm or more, the protrusion 22 can reduce the amount of retreat of the seat 19 due to the kickback phenomenon. , It is possible to suppress the occurrence of a paper feed error of the sheet 19 during continuous paper feed. That is, the height dimension H of the protrusion 22 is preferably 0.7 mm or more.

Next, some variations regarding the shape of the upper surface of the protrusion 22 will be described. FIG. 11 is a diagram showing another example regarding the shape of the upper surface of the protrusion 22. In the example of FIG. 11, a recess 22c corresponding to the outer shape of the auxiliary roller 40 is formed on the upper surface of the protrusion 22. In this case, when the auxiliary roller 40 is lowered as shown in FIG. 11, the auxiliary roller 40 presses the sheet 19 against the recess 22c. As a result, a plurality of bent portions 19a can be formed with respect to the seat 19, and the holding force of the seat 19 can be increased. As a result, the retreat of the seat 19 due to the kickback phenomenon can be suppressed more effectively.

FIG. 12 is a diagram showing a modified example of the recess 22c shown in FIG. For example, as shown in FIG. 12A, the recess 22c may be formed as a gentle slope on the downstream side in the paper feeding direction from the bottom of the recess 22c. In this case, the bent portion 19a of the seat 19 is generated at the top 22d of the protruding portion 22. Further, as shown in FIG. 12B, the recess 22c may be formed as a gentle slope on the upstream side in the paper feeding direction.

As described above, the sheet loading device 9 of the present embodiment has a configuration in which the protrusion 22 is provided on the upper surface of the sheet pushing plate 21 on the upstream side of the position where the paper feed roller 31 abuts on the upper end of the tip of the sheet 19. is there. When the seat 19 is loaded, the protruding portion 22 can form a bent portion 19a in which the seat 19 is bent at the tip end portion of the seat 19. Therefore, even if a kickback phenomenon occurs when the rear end portion of one sheet 19 passes through the nip portion between the paper feed roller 31 and the separation roller 32 due to the paper feeding by the paper feed roller 31, the protrusion 22 causes the paper feed. The generated bent portion 19a of the sheet 19 can suppress the retreat of the tip portion of the sheet 19, and it is possible to reduce the occurrence of paper feeding errors during continuous paper feeding.

Further, the protrusion 22 that is kicked onto the upper surface of the seat push-up plate 21 can suppress the tip of the seat 19 from retreating due to the kickback phenomenon regardless of the size of the seat 19, so that it is more than the conventional case. It has the advantage that it is simple to configure and can be realized at low cost. Further, since the protrusion 22 does not have a movable portion, it does not become a source of noise.

The preferred embodiment of the present invention has been described above. However, the present invention is not limited to the contents described in the above-described embodiment, and various modifications can be applied.

For example, in the above embodiment, it has been described that the protrusion 22 provided on the upper surface of the seat push-up plate 21 is provided at a position substantially at the center of the seat 19 in the width direction. However, the present invention is not limited to this, and for example, the width dimension L1 of the protrusion 22 may be formed to be the same as the width dimension L3 of the sheet 19, and is also the same as the width dimension of the sheet push-up plate 21. It may be formed to the dimensions. Even in such a case, since the protruding portion 22 can form the bent portion 19a of the sheet 19 on the downstream side in the paper feeding direction, the bent portion 19a can suppress the retreat of the sheet 19. is there.

Further, in the above embodiment, the case where the sheet loading device 9 is provided as the manual feed tray 10 on the side surface of the device main body 1a of the image forming device 1 is illustrated. However, the structure of the protrusion 22 described above is not limited to the manual feed tray 10, and can be applied to, for example, the document placing section 7 of the automatic document transport section 6. Therefore, the sheet loading device 9 described above may be mounted on the image forming apparatus 1 as the document placing section 7 of the automatic document transport section 6.

Further, in the above embodiment, the case where the image forming apparatus 1 is configured by the MFP is illustrated. However, the image forming apparatus 1 is not limited to the MFP. For example, the image forming apparatus 1 may be an apparatus having only a printing function.

1 Image forming device 9 Sheet loading device 10 Manual feed tray 11 Sheet loading part 19 Sheet 19a, 19b Bending part 21 Sheet push-up plate 22 Protruding part 22a Inclined part 22c Recessed 31 Paper feed roller 32 Separation roller 40 Auxiliary roller (roller member)

Claims (13)

The seat loading section for loading seats and
A sheet push-up plate that supports the tip of the sheet loaded on the sheet loading section and pushes up the tip of the sheet.
A paper feed roller that abuts on the upper end of the tip of the sheet loaded on the sheet loading unit to feed the sheet.
Separation in which one sheet located at the uppermost part of the plurality of sheets is separated and sent out to the downstream side when a plurality of sheets are fed by the paper feed roller in contact with the paper feed roller. With rollers
A protrusion provided on the upper surface of the sheet push-up plate on the upstream side at a position where the paper feed roller abuts on the upper end of the tip of the sheet.
A seat loading device characterized by being provided with. The seat loading device according to claim 1, wherein the protruding portion forms a bent portion at the tip end portion of the seat. The sheet loading device according to claim 1 or 2, wherein the protrusion is provided on the upstream side of a position where the paper feed roller abuts on the upper end of the tip of the sheet. The sheet loading device according to any one of claims 1 to 3, wherein the protrusion has a width dimension in a direction orthogonal to the paper feeding direction smaller than the width of the sheet. The sheet loading device according to claim 4, wherein the width dimension of the protrusion is 30% or less of the width dimension of the minimum size sheet. The sheet loading device according to any one of claims 1 to 5, wherein the protrusion is provided at a position substantially central of the width of the sheet on the upper surface of the sheet push-up plate. The sheet loading device according to any one of claims 1 to 6, wherein the protrusion has a height of 0.7 mm or more from the upper surface of the sheet pushing plate. The sheet loading device according to any one of claims 1 to 7, wherein the protruding portion has an inclined portion whose height gradually increases from the upstream side to the downstream side in the paper feeding direction. A roller member that is provided so as to be able to move up and down at a position above the protrusion, and that descends when the sheet is fed by the paper feed roller and comes into contact with the sheet loaded on the protrusion.
The sheet loading device according to any one of claims 1 to 8, further comprising. The sheet loading device according to claim 9, wherein the roller member has a width dimension in a direction orthogonal to the paper feeding direction, which is larger than the width of the protrusion. The sheet loading device according to claim 9 or 10, wherein a recess corresponding to the outer shape of the roller member is formed on the upper surface of the protrusion. An image forming apparatus comprising the sheet loading apparatus according to any one of claims 1 to 11. The image forming apparatus according to claim 12, wherein the sheet loading device is provided as a manual feed tray.

Images