JP2798144B2 - Paper feeder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeder suitable for use in an image forming apparatus such as a copying machine, a printer, a facsimile, and the like. The present invention relates to a structure for positioning.

[0002]

2. Description of the Related Art In an image forming apparatus such as a copying machine, a printer, a facsimile or the like (hereinafter referred to as a copying machine or the like), in order to form an image at a correct position on a sheet material, the sheet material in a correct posture is formed. Must be supplied to the equipment.

In order to correct the position of the sheet material, that is, to correct the skew of the sheet material and perform positioning, it is generally performed by a sheet feeding and conveying device. The method is roughly divided into two types.

[0004] First, there is a sheet feeder based on the leading edge of a sheet material, an example of which is shown in FIG.

This apparatus includes a feed roller 91 for conveying the sheet material P in the direction of arrow A, and a pair of upper and lower registration rollers 92a and 92b disposed downstream of the feed roller 91. If the conveyance of the sheet material P by the feeding roller 91 is continued even after the leading edge P1 of the sheet material P is brought into contact with the nip portion 93 of the stopped registration rollers 92a and 92b, the feeding roller 91 and the nip portion A loop for correcting skew is formed in the sheet material P between the sheet material P and the sheet material P, and the leading edge P1 of the sheet material P is pressed against the nip portion 93 by the loop, and the leading edge P1 follows the nip portion 93 correctly. Be placed. Thereafter, when the registration rollers 92a and 92b are driven to rotate, the sheet material P is conveyed in a state where the skew is corrected based on the leading edge P1.

In this case, the registration rollers 92a, 92b
Is set such that the left-right width of the nip portion 93 is longer than the length of the leading edge P1 of the sheet material P.

Another method of correcting the skew of the sheet material P is as shown in FIG.
Is performed on the basis of

In this apparatus, a reference guide 95 is provided along a conveying path of a sheet material P, and the sheet material P is conveyed forward (in the direction of arrow A) by conveying rollers 96 and oblique feeding rollers 97, 97. At the same time, it is moved in the horizontal direction (the direction of arrow B). Each of the skew feeding rollers 97 is given a predetermined skew feeding angle α1, α2, and the sheet material P being conveyed in the forward direction is moved in the lateral direction by a force corresponding to the skew feeding angles α1, α2 ( Hereinafter, this force is referred to as oblique feed force.) By sliding the side edge P2 into sliding contact with the reference guide 95, the side edge P2
Skew correction is performed on the basis of.

[0009]

However, according to the above-mentioned conventional example, when the skew is corrected, the length of the sheet P exceeds the length of the leading edge P1. The registration rollers 92a and 92b must be disposed, and a place for the sheet material P to form a skew correction loop needs to be secured. , The leading edge P1 is nip 9
3, there is a problem in that a temporal loss of temporarily stopping occurs, and it is difficult to increase the sheet material feeding speed.

On the other hand, with respect to the sheet material P based on the side edge P2, although the above-mentioned problem is solved,
There is a problem that it is difficult to appropriately set the skew feeding force of the skew feeding roller 97 on the sheet material P. That is, when the skew feeding force is excessive, the side edge P2 of the sheet material P reaches the reference guide 95 quickly and the skew correction is performed in a short time. Therefore, there is a fear that it is easily damaged. Conversely, if the skew feeding force is too small, there is little fear of damaging the side edge P2, but there is a problem that it takes a long time to correct the skew.

Therefore, the present invention makes it possible to adjust the skew feeding force to the sheet material, thereby eliminating structural and space waste and time loss, and preventing damage to the side edges of the sheet material. It is an object of the present invention to provide a paper feeding and conveying device which has been eliminated.

If the side edges of the sheet material are damaged, not only the value as a product is reduced, but also a conveyance error such as a jam may occur.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a sheet material sandwiched between a conveying roller and a skew feeding roller is gradually conveyed in a forward direction while being conveyed in a forward direction. , And the sheet feed roller is slidably contacted with a reference guide to position the sheet material laterally in the lateral direction. And a biasing means for biasing the transport roller toward the reference guide when the transport roller separates from the reference guide.

In this case, a plurality of skew feeding rollers can be arranged along the outer peripheral surface of the conveyance roller, and the skew feeding roller has a predetermined skew angle with respect to the conveyance roller. The sheet member may be disposed and move the sheet material in the lateral direction based on the oblique feed angle. Further, the skew feeding roller may have a spiral groove on its peripheral surface for moving the sheet material in the lateral direction instead of providing the skew feeding angle.

[0015] In addition, the moving amount of the transport roller with respect to the reference guide can be changed within a range of 0.5 mm or more and 10 mm or less.

[0016]

According to the above construction, the sheet material sandwiched between the transport roller and the oblique feed roller is transported forward while
The sheet is gradually moved by the oblique feeding force in the lateral direction, and the distance between the side edge of the sheet material and the reference guide is gradually reduced. At this point, the transport roller, which is arranged to be movable in the lateral direction via the urging means, is rotating, but still has
There is no lateral movement with respect to the reference guide, so the biasing means remains in a natural state.

Then, when the conveyance and the movement with respect to the sheet material are continued, the side edge of the sheet material contacts the reference guide. Thereafter, the movement of the sheet material is further continued, that is, when the amount of the side edge of the sheet material fed out from the conveying roller and the skew feeding roller toward the reference guide increases, the side edge of the sheet material becomes the reference guide. The sheet material is pushed back by the reference guide by this reaction. As a result, the transport roller is moved laterally by the sheet material against the urging means, that is, in the direction away from the reference guide.

After the side edge of the sheet material contacts the reference guide, the side edge is pressed against the reference guide with a pressing force determined by the physical characteristics of the urging means.

Therefore, for example, if the pressing force of the urging means is generated with an appropriate magnitude, the skew correction is quickly performed by bringing the side edge into contact with the reference guide in a short time. Even in the case of damage, side edges are hardly damaged. That is,
The contact in a short time means that the sheet material is moved in the lateral direction by applying a large skew feeding force, but the side edge after the contact is replaced by this large skew feeding force. This is because the pressing means is pressed against the reference guide by an appropriate pressing force.

At this time, if a plurality of skew feeding rollers are provided, the skew feeding force can be dividedly applied to a plurality of portions of the sheet material, so that the posture of the sheet material being conveyed can be easily controlled. .

The skew feeding force on the sheet material can be controlled by arranging the skew feeding roller at a predetermined skew feeding angle with respect to the conveying roller or by forming a spiral groove on each peripheral surface. Can occur.

The skew correction of the sheet material can be effectively performed by setting the moving amount of the conveying roller with respect to the reference guide within a range of 0.5 mm or more and 10 mm or less.

[0023]

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

First, a laser beam type copying machine 1 is shown in FIG. 4 as an example of an image forming apparatus incorporating the sheet feeding and conveying apparatus 10 according to the present invention.

At the lower part of the copying machine 1, a paper feed cassette 20 for storing sheet materials P to be copied is mounted.
Inside the paper feed cassette 20, a middle plate 21 having a rear end portion 21a as a rotation center is disposed.
1b is urged upward by a spring 22 interposed between the sheet feeding cassette 20 and the bottom plate 20a. The sheet material P is laminated on the middle plate 21 which is urged upward, and the separation claw 2 is disposed at the top corner of the uppermost sheet material P from above.
3 are engaged. The separation claw 23 is swingable about a shaft 23a on the rear end side, and is placed on a corner of the sheet material P by its own weight.

Above the front end of the sheet material P, a circumferential portion 3
A paper feed roller 31 having a cutout 1a and a notch 31b is provided. When the feed roller 31 rotates, the circumferential portion 31 is rotated.
The uppermost sheet material P is separated from the separation claw 23 by friction with
The sheet is guided by a guide 20 b on the front end side of the sheet cassette 20, fed in the front direction (the direction of arrow A), and supplied to the sheet feeder 10.

The paper feeding and conveying device 10 includes a conveying roller 11 and
Skewing rollers 12a, 12 pressed against conveying roller 11
b, 12c, and the sheet material P supplied by the sheet feeding roller 31 is conveyed so as to be sandwiched between both rollers. The skew feeding rollers 12a, 12b, 12c
The arms 13a, 13b, and 13c are rotatably mounted on the distal ends of the arms 13a, 13b, and 13c. The arms 13a, 13b, and 13c have their base ends swingably supported, and have springs 15a, 15b, 15c is attached to the main body frame 1a. Further, a guide plate 16 for regulating the vertical position of the sheet material P is fixed to the main body frame 1a, and the sheet material P moves between the transport roller 11 and the guide plate 16 toward the image forming unit 50. Transported.

The conveying roller 11 and the skew feeding roller 12
The paper feeder 10 having the main components a, 12b, and 12c will be described later in detail.

The image forming section 50 has a photosensitive drum 52 disposed in a process cartridge 51. The photosensitive drum 52 is uniformly charged at a predetermined positive or negative potential by a primary charger (not shown) during the rotation process, and is then emitted from a laser scanner 60 at an exposure unit 53 and polarized by a mirror 55. The target image information is scanned and written by the laser beam scanning exposure L. Thus, an electrostatic latent image corresponding to the target image information is sequentially formed on the surface of the photosensitive drum 52. Photosensitive drum 52 on which latent image is formed
Then, the developing device 56 applies a developing material (toner) to develop the toner image as a toner image.

Next, the toner image is transferred to the transfer roller 5.
In the process of passing through the position 7, the sheet P is sequentially transferred between the transfer roller 57 and the photosensitive drum 52 onto the sheet material P fed one by one from the above-described sheet feeder 10. The transfer of the toner image from the photosensitive drum 52 to the sheet material P is performed by the transfer roller 57 disposed on the back surface of the sheet material P being charged with the polarity opposite to the charged electrode property of the toner image.

The sheet material P which has passed the position of the transfer roller 57 is subsequently arranged next to the transfer roller 57, and receives a charge reduction by a separation charge needle 59 applied to a potential having a polarity opposite to that of the transfer roller 57. As a result, the photosensitive drum 52 is separated.

Thereafter, the unfixed toner image on the sheet P introduced into the fixing device 70 is fixed on the sheet P as a permanent fixed image.

The sheet material P on which the image has been fixed is
The sheet is conveyed by a sheet discharge roller pair 71 and is discharged to a sheet discharge tray 72.

On the other hand, the photosensitive drum 52 after the transfer of the toner image
Is removed by a cleaning device (not shown) in the process cartridge 51, and is used repeatedly for image formation.

Next, the paper feeder 10 of the present invention will be described with reference to FIGS.

The paper feeder 10 is provided with the above described transport roller 1 disposed diagonally above the separation claw 23 of the paper feed cassette 20.
1. In addition to the skew feeding rollers 12a, 12b and 12c, a reference guide 17 and a compression spring 19 as urging means are provided.

Inside the reference guide 17, a smooth guide surface 17a is formed. The guide surface 17a regulates the position of one side edge P2 of the sheet material P in the lateral direction (the direction of arrow B) to position the entire sheet material P left and right, and corrects the skew of the entire sheet material P. Things. The guide surface 17a is positioned such that the position in the lateral direction B is
The sheet material P is stored so as to be located slightly outside the side edge P2 of the sheet material P stored in the sheet material P. That is, a width regulating plate 25 is provided in the sheet cassette 20, and a width guide surface 25a for regulating one side edge P2 of the sheet material P stored in the sheet cassette 20 is formed inside the width regulating plate 25. The distance Δ1 between the width guide surface 25a and the guide surface 17a of the reference guide 17 is set to a necessary minimum. In this embodiment, Δ1 is set to 1.5 mm. Introducing portion 17 closest to separation claw 23 of reference guide 17
In b, the separation claw 23 side is expanded so that the front end corner of the sheet material P at the time of sheet feeding does not catch on the reference guide 17.

At the center of the guide surface 17a of the reference guide 17, a mounting shaft 17c having a large-diameter stopper portion 17d at the end is protruded, and the transport roller 11 is mounted on the mounting shaft 17c in the lateral direction (in the direction of arrow B). ). A compression spring 19 is interposed between the inner end surface 11a of the transport roller 11 and the stopper 17d of the mounting shaft 17c. When the compression spring 19 is in a natural state, the compression spring 19 is located outside the transport roller 11. An appropriate gap d is formed between the end surface 11d and the guide surface 17a of the reference guide 17. Accordingly, when a lateral inner force, that is, a force in a direction that separates the transport roller 11 from the reference guide 17, acts on the transport roller 11, the compression spring 19 is shortened. It urges toward the guide 17. However, the characteristics of the compression spring 19 and the distance Δ2 between the end face 11a of the transport roller 11 and the stopper 17d are determined so that the amount of movement of the transport roller 11 with respect to the reference guide 17 is 0.5 mm or more and 10 mm or less. Shall be

The arms 13a, 13b, 13c, springs 15a, 15
b, 15c, the oblique feed rollers 12a, 12b, 12
c is pressed. Each oblique feed roller 12a, 12b, 1
The axis of 2c is slightly inclined with respect to the lateral direction (axial direction of the conveying roller 11) with slanting feed angles θ1, θ2, and θ3, respectively. An oblique feeding force for laterally moving this toward the reference guide 17 is applied.

The skew feeding angles θ1, θ2, θ3 are respectively set with respect to the respective skew feeding rollers
A cylindrical peripheral surface passing through the centers of a, 12b, and 12c is imagined and measured on this peripheral surface. In this embodiment, for example, θ1 = 0.5 degrees, θ2 = 4 degrees, θ2
3 is set to about 4 degrees. Also, the oblique feed roller 12
The pressing force of the transfer rollers 11a, 12b and 12c is about 400 g weight in total, and the skew feeding rollers 12a, 12b and 12c increase the skew feeding force for moving the sheet material P in the lateral direction by about 150 g weight. The maximum spring force of the compression spring 19 is about 70 g weight.

Next, the operation of the sheet feeder 10 will be described with reference to FIGS.

When the leading end of the sheet material P separated and conveyed from the sheet cassette 20 passes through the skew feeding roller 12a, a skew feeding force F1 acts on the sheet material P, but the leading end of the sheet material P
2b, the side edge P of the sheet material P is still being reached.
1 is not in contact with the reference guide 17, and the transport roller 11 remains at the predetermined position shown in FIG.

At this time, the skew feeding rollers 12a and 12b apply the skew feeding forces F1 and F2 for moving the sheet material P toward the reference guide 17 as they are.

Thereafter, as shown in FIG.
When the leading end of the sheet material P reaches the skew feeding roller 12c, the skew feeding force F3 of the sheet material P is applied to the sheet material P.
Before and after this, the side edge P1 of the sheet material P contacts the guide surface 17a of the reference guide 17.

At this time, for the first time, the sheet material P is moved from the reference guide 17 by a reaction force F equivalent to the oblique feeding force (F1 + F2 + F3).
0, the transport roller 11 receives the reaction force F0
From the sheet material P.

The total oblique feeding force is about 15 as described above.
0g weight is set, and this 150g weight is
When acting on 1, the spring force of the compression spring 19, which is about 70 g weight, is reduced to lose this oblique feeding force of about 150 g weight, and the transport roller 11 starts to move in the direction away from the reference guide 17 in the opposite direction.

In other words, when the transport roller 11 starts to move, a force F of about 70 g weight is applied to the sheet material P by the compression spring 19, and the side edge P 2 of the sheet material P is applied to the reference guide 17 by a force of about 70 g weight. Pressed.

That is, when the sheet material P is not in contact with the reference guide 17, the skew feeding rollers 12a, 12b, 12c
The skew feeding force F1, F2, F3 acts sufficiently on the sheet material P to quickly press the sheet material P against the reference guide 17, and once the sheet material P comes into contact with the reference guide 17, this time, The sheet material P is stably pressed against the reference guide 17 by the compression spring 19 at a constant force F having high accuracy and stability. Thereby, the sheet material P moves in a short time with a large skew feeding force until the sheet material P comes into contact with the reference guide 17, and after the sheet material P comes into contact with the reference material 17, the force is smaller than the skew feeding force and the compression spring 19 With the ability to follow
It is possible to prevent the side edge P2 of the sheet material P from being damaged by pressing the sheet material P.

The conveying roller 11 moves in the horizontal direction from the time when the sheet material P comes into contact with the reference guide 17 to the time when the sheet material P passes through the conveying roller 11, but in this embodiment, the moving amount at that time is about 3 mm. It was enough.

As the skew feeding roller for applying the skew feeding force to the sheet material P, for example, a roller as shown in FIG. 5 may be used. , And a spiral groove 12e is formed. According to this, without tilting the shaft 12f,
Even if the sheet P is arranged in the horizontal direction, that is, in parallel with the axis of the conveying roller 11, a skew feeding force can be applied to the sheet material P. 1
The oblique feed angles θ1, θ2, and θ3 of 2a, 12b, and 12c do not have to be appropriately set, and the structure is simplified.

The number of skew feeding rollers is not limited to three, but may be any number.
Further, the urging means may be, for example, leaf springs or a combination of a cylinder and a plunger, instead of the compression spring 19. That is, as long as the urging means effectively urges the transport roller 11, its structure may be arbitrary.

Further, in the present embodiment, the method of feeding the sheet material P is limited to the nail separation method. However, the paper feeding method may be other than the nail separation method. Needless to say.

In addition, the sheet feeder 10 according to the present invention
Can be expected to have substantially the same effect even when mounted on not only a copying machine but also another image forming apparatus such as a facsimile or a printer.

[0055]

As described above, according to the present invention,
With a simple structure in which the transport roller is movably mounted via the urging means, the sheet material can reach the reference guide in a short time, and thereafter, the sheet material is removed with a small force excellent in the followability of the urging means. Since it can be pressed against the reference guide, it is possible to positively eliminate structural, space, and time waste, and realize highly accurate skew correction and positioning without damaging the sheet material. .

[Brief description of the drawings]

FIG. 1 is an explanatory perspective view of the overall configuration of a paper feeder.

FIG. 2 is a front view showing the operation of the sheet feeding device.

FIG. 3 is a front view illustrating the operation of the sheet feeding and conveying device.

FIG. 4 is a vertical cross-sectional side view of a copying machine equipped with the sheet feeding device according to the embodiment.

FIG. 5 is a perspective view showing another embodiment of the oblique feed roller.

FIG. 6 is a perspective explanatory view showing a conventional example.

FIG. 7 is an explanatory perspective view showing another conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Paper feeder 11 Conveyor roller 11c Outer peripheral surface 12a, 12b, 12c Slanting roller 12e Streak groove 17 Reference guide 19 Urging means (compression spring) A Front direction B Lateral direction P Sheet material P2 Side edge θ1, θ2 θ3 Slant feed angle

Claims (5)

(57) [Claims] 1. A sheet material sandwiched between a conveying roller and a skew feeding roller is gradually moved in a lateral direction while being conveyed forward, and one side edge of the sheet material is slid on a reference guide. In the sheet feeding and transporting apparatus which performs lateral positioning of the sheet material in the lateral direction, the transporting roller is disposed movably in the horizontal direction, and the transporting roller is moved when the transporting roller is separated from the reference guide. A sheet feeding / conveying device, comprising: urging means for urging toward a reference guide. 2. The apparatus according to claim 1, wherein a plurality of the oblique feed rollers are arranged along an outer peripheral surface of the transport roller.
The paper feeding and conveying device according to the above. 3. The skew feeding roller is disposed at a predetermined skew feeding angle with respect to the conveyance roller, and moves the sheet material in a lateral direction based on the skew feeding angle. 3. The sheet feeding and conveying device according to claim 1 or 2. 4. The sheet feeding and conveying device according to claim 1, wherein the skew feeding roller has a spiral groove on a peripheral surface for moving the sheet material in a lateral direction. apparatus. 5. The sheet feeding and conveying device according to claim 1, wherein a moving amount of the conveying roller with respect to the reference guide changes within a range of 0.5 mm or more and 10 mm or less.