JP2005059980A - Sheet feeding apparatus and image forming apparatus - Google Patents

Abstract

When a sheet is supplied from a paper cassette, the curled sheet is likely to be skewed.
SOLUTION: Side regulating plates 12, 14 are movable walls 12a, 14a movable in the sheet width direction, and movable walls 12b, 14b are held by the fixed walls 12a, 14a so as to be movable in the sheet stacking direction. The movable walls 12b and 14b are configured by the flanges 12e and 14e protruding from the side end side of the sheet to the upper surface side of the sheet, and the seats of the fixed walls 12a and 14a regardless of the movement positions of the movable walls 12b and 14b. The control surface 14f has substantially the same control surface 14f, and even a curled sheet can be fed so as not to get over the side control plates 12 and 14, thereby reliably preventing the skew of the sheet from occurring. Make sheet feeding more stable.
[Selection] Figure 1

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a sheet feeding apparatus for supplying sheets to an image forming apparatus such as a printer or a copying machine.
[0002]
[Prior art]
FIG. 8 shows a conventional sheet feeding apparatus 100 mounted on the printer A as an image forming apparatus. The sheet feeding apparatus 100 includes a sheet cassette 101 for storing sheets shown in FIG. A sheet feeding unit 102 that feeds the sheets.
[0003]
As shown in FIGS. 8 and 9, the sheet cassette 101 holds an intermediate plate 104 on which sheets S are stacked so as to be swingable around the rear end side (upstream side in the conveyance direction, left side in the drawing). The sheet S to be stacked is abutted against the wall 106 of the paper cassette 101 on the sheet feeding side (the right side in the figure) in the printer A, and the sheet rear end (the left side in the figure) is the opposite side. It abuts against a rear end regulating plate 108 that can move according to the size of the sheet. Further, side restriction plates 110 and 112 that are movable in accordance with the size of the sheet are provided in a direction perpendicular to the conveying direction (the width direction of the sheet). Thus, the sheets S are positioned and stacked with only the upper surface side opened.
[0004]
The sheet feeding unit 102 is in contact with the upper surface of the stacked sheets S, picks up a roller 114 for feeding out the sheet, a feed roller 116 for rotating the sheet in the feeding direction, and a direction for returning the sheet into the sheet cassette 101. And a separation unit composed of a rotatable retard roller 118. A pair of conveyance rollers 120a and 120b for conveying the sheet is disposed on the downstream side of the separation unit.
[0005]
When the sheet S is fed into the printer A, the intermediate plate 104 swings upward by a lifter mechanism (not shown) and the pickup roller 114 is brought into contact with the upper surface of the sheet S. As the pickup roller 114 rotates, the sheet S is sent to the nip portion between the feed roller 116 and the retard roller 118. Therefore, the retard roller 118 rotates so as to feed the sheet in the direction opposite to the conveyance direction, so that only the uppermost sheet S is separated and conveyed to the next conveyance roller pair 120a, 120b, and the printer A Are supplied to an image forming unit (not shown).
[0006]
In the conventional sheet feeding apparatus, when the sheets are separated and fed, they may not be fed accurately along the transport direction and may be skewed. FIG. 10 shows a view in which the sheet is fed in a state inclined with respect to the conveyance direction. In this figure, the uppermost sheet Sa curls upward, for example, and the sheet passes over the side regulating plate 110. If the sheet feeding is continued in this state, the sheet skews due to the inclination of each roller.
[0007]
Regardless of the retard roller type separation unit, skew may occur in the same manner, for example, in a nail separation method for separating sheets using a separation nail 122 as shown in FIG. In particular, in the case of the nail separation method, when the sheet is separated, the corner portion of the sheet is bent and bounced.
[0008]
Therefore, in order to solve this problem, in the conventional paper cassette, a pressing member for pressing the upper surface of the side end portion of the sheet is provided, the curled sheet is pressed, and the curled sheet is inserted into the width regulating portion to suppress the skew. The thing is proposed (for example, refer patent document 1).
[0009]
[Patent Document 1]
Japanese Patent Laid-Open No. 07-117865
[Problems to be solved by the invention]
However, the technique disclosed in Japanese Patent Application Laid-Open No. 07-117865 cannot cope with the nail separation method as shown in FIG. In addition, since the sheet is pressed from the upper surface, an excessive force (deformation force) acts on the sheet and easily causes a feeding failure, and the pressing force (deformation force, correction force) is released immediately after feeding. On the other hand, it has a problem that it is easy to cause skewing.
[0011]
The present invention has been made in view of the above problems, and an object of the present invention is to provide a sheet feeding apparatus that can feed even a curled sheet without skewing.
[0012]
[Means for Solving the Problems]
The present invention includes a sheet storage unit that stacks and stores sheets and detachably attaches to the apparatus main body, and a sheet feeding unit that separates and feeds sheets one by one from the storage unit. In the feeding device, the sheet storage unit includes a side regulating unit for regulating a side end of the stacked sheets, and the side regulating unit includes a side regulating plate movable in a sheet width direction, The side regulating plate is provided with a movable side regulating plate that is held so as to be movable in the sheet stacking direction. The movable side regulating plate includes a flange that protrudes from the side end side of the sheet to the upper surface side of the sheet, and the movable Regardless of the movement position of the side regulating plate, the side regulating plate has a regulating surface substantially the same as the regulating surface of the sheet.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
(First embodiment)
FIG. 1 is a perspective view of a paper cassette of the sheet feeding apparatus according to the first embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view of a printer in which the paper cassette is detachably mounted.
[0014]
The configuration of the printer A will be described with reference to FIG. A sheet feeding device 1 is disposed below the printer A. The sheet feeding apparatus 1 includes a sheet cassette 2 that stores sheets and a sheet feeding unit 4 that feeds sheets from the sheet cassette 2.
[0015]
In the paper cassette 2, an intermediate plate 6 on which sheets S are stacked is held swingably in the cassette container 2a around the rear end side (upstream in the transport direction, left side in the figure). The sheet S to be stacked is abutted against the wall 8 formed in the cassette container 2a on the right side in the drawing in which the sheet is fed into the printer A, and is the opposite side of the sheet rear end (left side in the drawing). A rear end regulating plate 10 is arranged which is movable according to the size of the sheet. Further, with respect to a direction perpendicular to the conveying direction (sheet width direction), side regulating plates 12 and 14 are provided that are movably attached to the cassette container 2a according to the size of the sheet. As a result, the sheets S are stacked in a state in which only the upper surface side is opened.
[0016]
The sheet feeding unit 4 is in contact with the upper surface of the stacked sheets S and picks up a roller 16 for feeding out the sheet, a feed roller 18 for rotating the sheet in the feeding direction, and a direction for returning the sheet into the sheet cassette 2. And a separation unit composed of a rotatable retard roller 20. A pair of conveyance rollers 22 and 24 for conveying the sheet is disposed on the downstream side of the separation unit. The intermediate plate 6 is brought into pressure contact with the pick-up roller 16 with the sheets being lifted and stacked by a lifter mechanism (not shown).
[0017]
The sheet fed by the pair of conveyance rollers 22 and 24 is guided by the sheet conveyance path 26 and is sent to the image forming unit F. A registration shutter 28 is provided in the middle of the sheet conveyance path 26.
[0018]
The image forming unit F includes a process cartridge 38 including a photosensitive drum 30, a charging roller 32, a developing roller 34, a cleaning blade 36, an exposure device 40 for irradiating the photosensitive drum 30 with laser light, and a photosensitive drum 30. And a fixing roller 44 arranged on the downstream side of the process cartridge 38. A discharge roller 48 for discharging the image-formed sheet onto the discharge tray 46 is provided on the downstream side of the fixing device 44.
[0019]
Here, an image forming operation in the printer A will be described.
[0020]
When the sheet S is fed into the printer A, the pick-up roller 16 is brought into contact with the upper surface of the sheet S as the middle plate 6 swings upward. As the pickup roller 16 rotates, the sheet S is sent to the nip portion between the feed roller 18 and the retard roller 20. Therefore, when the retard roller 20 rotates so as to feed the sheet in the direction opposite to the conveyance direction, only the uppermost sheet S is separated and conveyed to the next conveyance roller pair 22 and 24 to be transferred to the printer A. The image forming unit F is supplied.
[0021]
Next, when the sheet reaches the registration shutter 28 on the conveyance path 26, the leading edge of the sheet S abuts on the registration shutter 28 which is pre-pressurized by a spring (not shown) and is held rotatably. At this time, the skew of the sheet is corrected because the registration shutter 28 is rotated while the leading edges of the sheets S are aligned at right angles to the conveyance direction. When the registration shutter 28 is rotated to a predetermined position, a flag portion (not shown) provided on the registration shutter 28 blocks an optical path of a photosensor (not shown) to output an image writing signal.
[0022]
The sheet S further proceeds on the conveyance path 260 and reaches the photosensitive drum 30. The photosensitive drum 30 is uniformly charged by the charging roller 32 in response to the image writing signal. Further, an electrostatic latent image corresponding to the image information is formed on the surface of the photosensitive drum 30 by scanning the laser beam modulated by the exposure device 40. The electrostatic latent image is developed as a toner image by attaching toner to the developing roller 34. The toner image on the photosensitive drum 30 is transferred by the transfer roller 42 onto the surface of the sheet S conveyed to the photosensitive drum. The sheet S after the transfer of the toner image is heated and pressed by the fixing device 44 to fix the toner image on the surface. Thereafter, the sheet S is discharged onto the discharge tray 46 via the discharge roller 48.
[0023]
After the toner image is transferred, the toner remaining on the surface of the photosensitive drum 30 is removed by the cleaning blade 36 and used for the next image formation.
[0024]
The paper cassette 2 will be described in detail with reference to FIG.
[0025]
The side restricting plates 12 and 14 as the side restricting means of the present invention are movable according to the size of the sheet, and are fixed at the restricting position according to the size. The fixed walls 12a and 14a as the side restricting plates of the present invention. And movable walls 12b and 14b as movable side regulating plates of the present invention made of synthetic resin.
[0026]
The fixed wall 12a is provided with cylindrical portions 12c and 12c, and slits 12d and 12d provided on the movable wall 12b are movably held in the cylindrical portions 12c and 12c. With this configuration, the movable wall 12b moves to increase the side restricting plate 12. The side regulating plate 14 has the same configuration as the side regulating plate 12. In addition, flanges 12e and 14e having a shape protruding from the side end side of the sheet to the upper surface side of the sheet are formed on the upper portions of the movable walls 12b and 14b.
[0027]
Further, the structure of the side regulating plates 12 and 14 will be described in detail with reference to FIG. 3 (the side regulating plate 14 will be described as a representative). The movable wall 14b is formed such that a regulating surface 14f in contact with the end portion of the sheet extends downward from the flange portion 14e as a rib having the same height as the thickness of the fixed wall 14a. That is, the rib enters the notch portion of the fixed wall 14a, and the restricting surface 14f of the rib is substantially the same surface as the restricting surface 14g in contact with the sheet of the fixed wall 14a. Even when the movable wall 14b is at the highest position (upper position) in the vertical direction, the regulating surface 14g and the regulating surface 14f constitute the same surface. Thus, the sheets S are stacked in a state where only the upper surface side is opened except for the flange portions 12e and 14e.
[0028]
When the sheet S is fed into the printer A, the middle plate 6 swings upward by a lifter mechanism (not shown), so that the upper surface of the sheet S is pressed against the pickup roller 16. At this time, if the sheet tries to exceed the side regulating plates 12 and 14, the flanges 12e and 14e of the movable walls 12b and 14b are pushed up by the upper surface of the sheet, and the height of the side regulating plates 12 and 14 is increased. As the pickup roller 16 rotates, the sheet S is sent to the nip portion between the feed roller 18 and the retard roller 20. Therefore, the retard roller 20 rotates so as to feed the sheet in the direction opposite to the conveyance direction, so that only the uppermost sheet S is separated and conveyed to the next conveyance roller pair 22, 24. Thereafter, the sheet S is conveyed through the printer along the conveyance path 26.
[0029]
According to the present invention, even if the sheet S with the peripheral portion curled upward is stored in the paper cassette 2, the peripheral curled portion of the sheet S pushes up the eaves 12e and 14e by the upward swing of the intermediate plate 6. Thus, the movable walls 12b and 14b are lifted. As a result, the sheet does not exceed the side regulating plate, and it is possible to avoid feeding the sheet obliquely. Further, at this time, the regulation surface 14f in contact with the sheet of the movable wall 14b is substantially the same surface as the regulation surface 14g in contact with the sheet of the fixed wall 14a, and always overlaps in the height direction even if the movable wall 14b moves. Even if the movable wall 14b moves upward, no gap is formed between the movable wall 14b and the fixed wall 14a (not shown, but the same is true for the side regulating plate 12). Thereby, the sheet can be fed without hindering the conveyance of the sheet.
[0030]
In the present embodiment, the movable wall is made of synthetic resin, but the same effect can be obtained even when the sheet metal is light enough not to affect the behavior of the sheet due to its own weight, and the collar is not on the entire upper surface of the movable wall. .
[0031]
As explained above, the curled sheet edge is caught on the hook by having the side restricting plate that is variable in the direction of increasing the height, and having the hook protruding above the side restricting plate above the sheet. It is possible to prevent the seat from getting over the side regulating plate. Furthermore, since the height of the side regulating plate is increased, an unnecessary force is not applied to the sheet by the collar portion, and even a curled sheet can be fed without being inclined in the conveyance direction.
[0032]
(Second Embodiment)
FIG. 4 is a paper cassette showing the second embodiment. Note that only the parts different from the first embodiment will be described in detail, and the other parts are the same as those of the first embodiment, and the description thereof will be omitted.
[0033]
The side regulating plates 50 and 52 are composed of fixed walls 50a and 52a and movable walls 50b and 52b, and the opposing side regulating plates have symmetrical configurations. The fixed wall 50a is provided with shafts 50c on the left and right, and a hole 50h of the movable wall 50b is held as a swing center on the shaft 50c on the upstream side (left side in the figure) in the transport direction. On the other hand, the slit 50d of the movable wall 50b is movably held so as to guide the swinging of the movable wall 50a on the shaft 50c on the downstream side in the transport direction (right side in the figure). The side regulating plate 52 has the same configuration. On the movable walls 50b and 52b, flanges 50e and 52e are formed, respectively.
[0034]
It should be noted that a rib (not shown) having a regulating surface in contact with the sheet end portion of the movable walls 50b, 52b having the same height as the thickness of the fixed walls 50a, 52a is formed to extend downward from the flange portions 50e, 52e. In the first embodiment, the configuration is such that the notch portions (not shown) of the fixed walls 50a and 52a (not shown) and the restricting surfaces of the ribs and the restricting surfaces contacting the sheets of the fixed walls 50a and 52a are substantially the same surface. It is the same as the form.
[0035]
The middle plate 6 has a structure that lifts with the upstream side in the conveyance direction (left side in the figure) as a swing center. The sheet S placed on the intermediate plate 6 is lifted on the downstream side in the conveyance direction (right side in the figure) by a lifter mechanism (not shown), and the upper surface of the sheet S is pressed against the pickup roller 16. Accordingly, the upper surface of the sheet S pushes up the flange portions 50e and 52e of the movable wall to raise the side regulating plates 50 and 52. When the pickup roller 16 rotates in this state, the sheet S is supplied into the printer A along the side regulating plates 50 and 52.
[0036]
According to the present embodiment, since the movable walls 50b and 52b are also oscillated in accordance with the oscillation of the middle plate 6, the sheet does not exceed the side regulating plates 50 and 52, and the sheet is fed without being skewed. The
[0037]
(Third embodiment)
FIG. 5 shows a paper cassette of the nail separation type that is mounted on the sheet feeding apparatus according to the third embodiment. The configuration of the movable walls 60b and 62b attached to the side regulating plates 60 and 62 is the same as that of the first embodiment, and only the attachment position is different. Note that only the parts different from the first embodiment will be described in detail, and the other parts are the same as those of the first embodiment, and the description thereof will be omitted.
[0038]
The separation claws 64 are provided at two upper portions of both corners on the downstream side of the conveyance of the sheet S. The separation claw 64 is shaped to cover the upper side of the sheet S and the right end (front end) in the drawing. The separation claw 64 also moves up and down somewhat as the sheet S moves. When feeding the sheet, the sheet S abuts against the separation claw 64 by the rotation of the pickup roller 16. Thereafter, the sheet S bends and overcomes the separation claw 64, and at that time, the sheet S is separated into one sheet. When separating the sheet S, the sheet S pushes up the flanges 60e and 62e of the movable walls 60b and 62b. Thereby, the side regulation plates 60 and 62 can be made high. Therefore, the seat S does not get over the movable walls 60b and 62b.
[0039]
Even in the nail separation type feeding according to the present embodiment, the sheet is not fed over the movable wall and is fed along the side regulating plate, and is not skewed.
[0040]
(Fourth embodiment)
FIG. 6 is a cross-sectional view of the paper cassette viewed from the sheet feeding direction according to the fourth embodiment. Note that only the parts different from the first embodiment will be described in detail, and the other parts are the same as those of the first embodiment, and the description thereof will be omitted.
[0041]
As for the side regulation plates 70 and 72 of the paper cassette 2, one side regulation plate 72 is a movable side regulation plate as in the first to third embodiments, and the other side regulation plate 70 is an elastic member of the present invention. It is comprised by the leaf | plate spring 70b. The height of the leaf spring 70b is higher than the position higher than the flange portion 14e (, 52e, 62e) of the movable wall 14b (, 52b, 62b), and has a shape that warps toward the sheet S as it goes upward.
[0042]
According to the present embodiment, the leaf spring 70b generates a force that pushes the sheet bundle S toward the one side regulating plate 72 and downward. Thereby, since the sheet S is moved toward the movable wall and fed, the conveyance of the sheet is more stable. Further, since the sheet S is warped toward the sheet S, the sheet S can be prevented from floating.
[0043]
Thus, by providing an elastic member as the other side regulating plate and applying a force so that the sheet abuts against the reference side side regulating plate, positional accuracy in the direction perpendicular to the sheet conveying direction is improved. Can do well. In addition, the configuration of the paper cassette can be simplified by using only one configuration in which the height of the side regulating plate is variable.
[0044]
(Fifth embodiment)
FIG. 7 shows a paper cassette showing the fifth embodiment. Note that only the parts different from the first embodiment will be described in detail, and the other parts are the same as those of the first embodiment, and the description thereof will be omitted.
[0045]
As in the second embodiment, the side regulating plates 70 and 72 include fixed walls 70a and 72a and movable walls 70b and 72b. The side regulating plate 70 includes a movable wall 70b on the fixed wall 70a. It is rotatably supported. The side regulating plate 72 has the same configuration. In addition, a rib (not shown) having a surface in contact with the sheet end of the movable walls 70b, 72b having the same height as the thickness of the fixed walls 70a, 72a is formed to extend downward from the flanges 70e, 72e, The first embodiment will be described with respect to the configuration in which the restriction surfaces of the ribs and the restriction surfaces contacting the sheets of the fixed walls 70a and 72a are substantially flush with the notch portions (not shown) of the fixed walls 70a and 72a. The form is the same.
[0046]
The height of the movable wall 70b is the lowest position when the paper cassette 2 is removed from the printer A, and the member provided in the printer A by the operation of mounting the paper cassette 2 on the printer A. (Not shown) pushes the trigger 75 in the arrow X direction. Thereafter, when the trigger 75 pushes the movable wall 70b, the movable wall 70b rotates to increase the height of the side regulating plate. The side regulating plate 72 performs the same operation.
[0047]
According to the present embodiment, it is possible to provide means for preventing the sheet from moving the movable wall directly. Accordingly, since the sheet is not always in contact with the flange portions 70e and 72e of the movable walls 70b and 72b, it is possible to perform more stable feeding without being affected by this.
[0048]
In the present embodiment, the movable wall 70b is moved by pressing the trigger 75 by a member of the printer main body, but the same effect can be obtained by using other mechanisms using power such as a motor.
[0049]
【The invention's effect】
As described above, according to the present invention, it is possible to reliably prevent sheet skew and to stabilize sheet feeding.
[Brief description of the drawings]
FIG. 1 is a perspective view showing a paper cassette according to a first embodiment of the present invention. FIG. 2 is a schematic sectional view of a printer apparatus incorporating a sheet feeding apparatus according to the present invention. FIG. 4 is a perspective view showing a sheet cassette according to a second embodiment of the present invention. FIG. 5 is a perspective view showing a sheet cassette according to a third embodiment of the present invention. FIG. 6 is a perspective view showing a paper cassette according to a fourth embodiment of the present invention. FIG. 7 is a perspective view showing a paper cassette according to a fifth embodiment of the present invention. FIG. 9 is a perspective view showing a sheet cassette as a conventional feeding apparatus. FIG. 10 is a perspective view showing a sheet cassette showing a conventional feeding state. Figure showing a conventional paper cassette of the nail separation method.
2 Paper cassette 6 Middle plate 10 Rear end regulating plate 12, 14 Side regulating plate 16 Pickup roller 12a, 14a Fixed wall 12b, 14b Movable wall 70b Plate spring 75 Trigger 122 Separation claw

Claims (7)

In a sheet feeding apparatus comprising a sheet storage unit that stacks and stores sheets and is detachably attached to the apparatus main body, and a sheet feeding unit that separates and feeds sheets one by one from the storage unit,
The sheet storage portion includes side restriction means for restricting the side edges of the stacked sheets, and the side restriction means includes a side restriction plate movable in the sheet width direction, and the side restriction plate. A movable side restriction plate that is held so as to be movable in the sheet stacking direction. The movable side restriction plate includes a flange that protrudes from the side end side of the sheet toward the upper surface side of the sheet, and the movable side restriction plate. A sheet feeding device having a regulation surface substantially the same as the regulation surface of the sheet of the side regulation plate regardless of the movement position of the sheet. The sheet feeding device according to claim 1, wherein the movable side regulating plate is provided on the side regulating plate so as to be slidable in the vertical direction. The sheet feeding device according to claim 1, wherein the movable side regulating plate is provided on the side regulating plate so as to be pivotable in a vertical direction. The side regulating means according to any one of claims 1 to 3 is arranged so as to regulate one side edge of the sheets stacked on the sheet storage portion, and the other side edge of the sheet is arranged. The regulating side regulating means has a height that is greater than or equal to the maximum variable height of the movable side regulating plate, and exerts a force that pushes the sheet toward the side regulating means that regulates one side edge and downward. A sheet feeding device comprising an elastic member having a generated shape. The movable side regulating plate is provided in conjunction with a lifter mechanism for pushing up the intermediate plate provided with a swingable intermediate plate loaded with sheets in the sheet storage unit, and in conjunction with the pushing-up operation of the intermediate plate by the lifter mechanism The sheet feeding apparatus according to any one of claims 1 to 4, wherein the sheet feeding device is moved. 5. The sheet feeding apparatus according to claim 1, wherein the movable side regulating plate moves in accordance with the attachment and detachment of the sheet storage portion to the apparatus main body. The sheet feeding device according to any one of claims 1 to 6,
An image forming apparatus comprising: an image forming unit that forms an image on a sheet fed by the sheet feeding device.

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