JPH1159939A - Automatic paper feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent an accident of overlapped delivery that a second sheet residing in the neighbourhood of a separating roller after separating motion is finished is carelessly carried under a separating roller method. SOLUTION: An automatic paper feeding roller is controlled to make a separating roller 4 contact with a pick roller 3b through a sheet 1a at the time of feeding the sheets and to separate the separating roller 4 and a sheet 1 from the pick roller 3b at the time of not feeding the sheets. Thereafter, weight rollers 38a, 38b fitted with a play on a shaft 3J formed roughly in the same diameter as the pick roller 3b are moved in the lower surface direction of a sheet cassette 2 by dead weight at the time of not feeding the sheets and drop and separate the sheet 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art FIG.
FIG. 3 is a cross-sectional view showing a conventional automatic paper feeder disclosed in Japanese Patent Application Publication No. 3 (JP-A) No. 3-2003. In the drawing, 1 is a sheet, 2 is a sheet cassette for storing the sheet 1, 3 is a pick roller for taking out the sheet 1 in the sheet cassette 2, 4 is a sheet for separating the sheet 1 taken out by the pick roller 3 and sending it out one by one The separation rollers 5 and 5 are coil springs as urging means for bringing the sheet 1 in the sheet cassette 2 into contact with the pick roller 3.

Next, the operation will be described. The leading end of the paper 1 in the paper cassette 2 is pushed up by the coil spring 5, and the uppermost paper 1 is in contact with the lower surface of the pick roller 3. Further, a separation roller 4 is provided so as to be in rolling contact with the pick roller 3. When the pick roller 3 is rotated in the paper transport direction in the above state, the paper 1 is taken out from the paper cassette 2.

When one sheet of paper 1 taken out of the paper cassette 2 is taken out, the conveyance force of the paper 1 due to the frictional force between the pick roller 3 and the paper 1 causes the separation roller 4 to separate the paper 1 in the direction of the dashed arrow. Since the setting is made so as to overcome the torque, the separation roller 4 is driven to rotate by the rotation of the pick roller 3, and sends the sheet 1 to the next step.

When two sheets 1 taken out of the sheet cassette 2 are taken out, the separation torque of the separation roller 4 is set so as to overcome the frictional force between the two sheets 1. Then, the separation roller 4 rotates in the direction indicated by the wavy arrow to separate the sheet 1 and feeds only one sheet to the next step.

[0006]

However, in the configuration of the automatic paper feeder shown in FIG. 10, since the separation roller 4 is always in contact with the pick roller 3, the separated paper 1 is returned into the paper feed cassette 2. Without being picked up, it is located near the paper separating portion 19 which is the contact portion between the pick roller 3 and the separating roller 4.
The rotation of the pick roller 3 must be stopped immediately after the trailing end of the separated and fed one sheet 1 has passed the separating section 19, and the separated sheet 1 located near the separating section 19 will be separated. Thus, there is a problem in that multi-feeding of sheets that are conveyed following the sheet 1 that has been sent out only one sheet occurs.

Further, since a rotational torque is always generated in the separation roller 4 in a direction opposite to the conveying direction of the sheet 1, if the separation roller 4 is always in contact with the pick roller 3, At the time of sheet conveyance, there may be a speed difference between the conveyance speed of the sheet 1 and the peripheral speed of the separation roller 4 on the contact surface of the sheet 1 with the separation roller 4. There are problems such as the possibility of causing a defect such as a roller mark.

Further, in the configuration of the automatic paper feeder shown in FIG. 10, the leading end of the paper 1 in the paper feed cassette 2 is constantly pushed up by the coil spring 5, and the uppermost paper 1 is the lower surface of the pick roller 3. , The paper 1 may always be taken out from the paper cassette 2 while the pick roller 3 is rotating in the paper 1 transport direction, and thus the paper may be double fed. There is a problem.

The paper 1 in the paper cassette 2 is pushed up by a coil spring 5 and the paper 1 is picked up by a pick roller 3.
The pressing force when the sheet 1 is brought into contact with the lower surface of the pick roller 3 is determined by the coil spring 5, and the paper 1 is stacked on the sheet cassette 2. The pressing force varies depending on the amount and the type of the sheet 1, and the sheet to be used is limited.

Further, there is a problem that the force of the pick roller 3 to take out the paper 1 from the paper cassette 2 is not stable, which may cause misfeed of the paper.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and it is intended to take out a sheet from a sheet cassette without multifeeding or misfeeding, and to cause defects such as scratches on the sheet surface. It is an object of the present invention to obtain an automatic sheet feeding apparatus which can handle various types of sheets having different characteristics and different characteristics at low cost without impairing the sheet separating performance.

[0012]

In the automatic paper feeder according to the present invention, the separation roller is brought into contact with the pick roller via the paper when feeding paper, and the separation roller is brought into contact with the pick roller when paper is not fed. The paper roller is controlled to be separated from the pick roller, and the weight roller, which is formed to have substantially the same diameter as the pick roller and is loosely fitted to the shaft supporting the pick roller, has its own weight when the paper is not fed. It moves in the direction of the lower surface.

The amount of movement of the weight roller due to its own weight is
It is smaller than the moving amount of the separation roller. Also,
The weight roller is formed so that it can be divided in the radial direction of the shaft to be loosely fitted. Further, the control means drives the lifter to move the sheet so as to contact the pick roller after the first sheet is conveyed, and to rotate the pick roller in the direction opposite to the sheet take-out direction.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 FIG. FIG. 1 is a perspective view showing a first embodiment of an automatic sheet feeder according to the present invention, and FIG. 2 is a block diagram of a control mechanism section thereof. In the figure, 1 is a sheet, 2 is this sheet 1
Paper cassettes 3a, 3b and 3c are fixed to the shaft 3J and driven by a step motor 36 (FIG. 2).
The pick roller 3 for taking out the paper 1 is divided into three, a separating roller 4 for separating the paper 1 taken out of the paper cassette 2 by the pick roller 3b, and a lifter 6 for bringing the paper 1 into and out of the pick roller 3. , 7 are levers that support the separation roller 4 and are configured to be rotatable about a shaft 17. The separation roller 4 is separated from the pick roller 3 by a spring 11 serving as an urging means.
b, the separation roller 4 and the pick roller 3
A contact pressure is applied to the separation portion 19 (FIG. 4), which is a contact portion with b. Note that one end of the spring 11 is locked to the housing of the automatic paper feeder.

The lifter 6 is connected to a cam 8 via a spring 10, and is configured to be rotatable about a shaft 18 by rotation of the cam 8. The cam 8 is rotationally driven by a step motor 30 (FIG. 2) as a driving source, and controls the position of the lever 7 via a follower 9.

The driving force of the pick rollers 3a, 3b and 3c is transmitted from the pick roller gear 12 to the separation roller gear 13 via gears 15 and 16, and the separation roller 4 is driven. The torque limiter 14 is connected to the gears 15 and 16. If the relative rotation torque of the rotation torque applied to the gears 15 and 16 is within the set torque of the torque limiter 14, the gears 15 and 16 rotate in the same phase.

Reference numerals 22a and 22b denote feed rollers for transporting the paper 1 separated by the separation unit 19 (FIG. 4) to the next step.
In order not to interfere with the separation roller 4, the spring 23 (FIG. 3) as a biasing means is configured to contact the pick rollers 3a and 3c. Feed roller 2
The feed rollers 2a and 22b are free to rotate with respect to the feed roller shaft 24, and the feed rollers 22a and 22b themselves have no driving force, and are configured to rotate following the rotation of the opposing pick rollers 3a and 3c. Since the feed rollers 22a and 22b do not require a driving force, cost reduction can be expected.

38a and 38b (FIG. 3) are pick rollers 3
A weight roller having substantially the same diameter as a and 3b and loosely fitted to the shaft 3J, and moves toward the lower surface of the paper cassette 2 by its own weight when paper is not fed. Further, when the separation roller 4 is in contact with the pick roller 3b, that is, when the sheet 1 is separated (FIG. 4), the center axes of the pick rollers 3a, 3b, 3c and the center axes of the weight rollers 38a, 38b are substantially aligned. Matches. On the other hand, when the separation roller 4 and the pick roller 3b are not in contact with each other, that is, when the paper 1 is not fed (FIGS. 3, 5, and 6), the weight rollers 38a and 38b are connected to the pick rollers 3a, 3b, and 3c. Is suspended from the shaft (axis 3J), and the weight rollers 38a and 38b press the paper 1 downward.

When the pick roller 3b is driven to rotate in the direction of transporting the sheet 1 in a state where the separating roller 4 is urged to the pick roller 3b (during paper feeding), the separating roller 4 is driven to rotate (co-rotate) by the pick roller 3b. ). The set torque of the torque limiter 14 and the contact pressure of the separation unit 19 (FIG. 4) given by the spring 11 are such that when one sheet 1 passes through the separation unit 19, the separation roller 4 is moved in the direction of the solid arrow (FIG. 4). Then, the sheet 1 is fed by the rotation of the pick roller 3b. When two or more sheets 1 pass through the separation unit 19, the separation roller 4 is set to rotate in the direction of the wavy arrow (FIG. 4) in the direction opposite to the sheet 1 conveyance direction. When the sheet 1 enters, the separation roller 4 separates the sheet 1.

Reference numeral 31 (FIG. 2) denotes pick rollers 3a, 3b,
The control unit 3c controls operations of the separation roller 4, the lifter 6, and the like.

Next, the operation will be described. 3 and 4,
5 and 6 are sectional views showing the operation of the automatic paper feeder according to the first embodiment of the present invention. FIG.
5 shows a paper feed state, FIG. 5 shows a transport state, and FIG. 6 shows a transport end state.

As shown in FIG. 3, the initial state (when no paper is fed)
In, the spring 11 is in a compressed state,
Around the shaft 17, a moment in the direction of the arrow due to the restoring force of the spring 11, one end of which is locked to the housing of the automatic sheet feeder, acts on the separation roller 4 attached to the lever 7.
Is exerted in the direction of rotation in the direction of the dashed arrow around the shaft 17, but the position of the lever 7 is regulated by the cam 8 via the follower 9, and the separation roller 4 is positioned away from the pick roller 3b. Is held at The weight rollers 38a and 38b are in a state hanging from the shaft 3J.

As shown in FIG. 4, in the paper feeding state,
When the cam 8 is rotated by a certain angle in the direction of arrow a by the step motor 30, the lever 7 is moved through the follower 9.
Release the position restrictions for. Lever 7 whose position has been released
Is the arrow b around the shaft 17 due to the restoring force of the spring 11
The separation roller 4 supported by the lever 7 is brought into contact with the pick roller 3b. When the cam 8 is rotated in the direction of the arrow a, the lifter 6 connected by the spring 10 rotates about the shaft 18 to push up the paper 1 in the paper cassette 2, press the paper 1 against the pick roller 3, and feed the paper. The paper 1 is taken out of the paper cassette 2 by generating pressure and driving the pick roller 3 by the step motor 36.

Since the weights of the weight rollers 38a and 38b are smaller than the pressing force of the lifter 6 and the separation roller 4 to the pick roller 3b, the weight rollers 38a and 38b are positioned concentrically with the pick rollers 3a, 3b and 3c. I do.

As shown in FIG. 5, after the paper feeding is completed, that is, after the paper 1a is sent out by the separation roller 4 and the pick roller 3b by a predetermined distance (non-printing area) in the downstream direction, the step motor 30 is turned off. The cam 8 is rotated in the reverse direction to the direction of the arrow a shown in FIG. 4 to return the lifter 6 to the initial position shown in FIG. 2, and the paper 1 pressed against the pick roller 3 is put into the paper cassette 2. return. The position of the lever 7 is regulated by the cam 8 via the follower 9 and returned to the initial position shown in FIG.
b.

During conveyance of the sheet 1a as shown in FIG.
Since the sheet 1 is constrained by the transport rollers 22a and 22b, the weight rollers 38a and 38b move in the lower left direction in FIG. 5, and the sheets 1a and 1b move in the lower direction of the sheet cassette 2. The weight rollers 38a and 38b loosely fitted on the shaft 3J separate the second sheet 1b from the pick rollers 3a, 3b and 3c, that is, the curl of the sheet 1 and the attraction force due to electrostatic charging. The second sheet 1b is moved by the pick roller 38 in response to the action force that is going to be double-fed by blocking the sheets due to the small edge cutting.
a, 38b. Therefore, even if the paper 1 set on the paper tray 2 is curled, electrostatically charged, and blocked, the weight rollers 38a, 38
b causes the second sheet 1b to drop onto the tray 2 in response to the force of drawing the second sheet 1b to the pick roller 1, so that the sheets conveyed from the sheet feeding device are separated one by one without double feeding. Becomes

As shown in FIG. 5, when the sheet 1b is in close contact with the sheet 1a, the sheet 1b is brought close to the separation roller 4 and separated from the sheet 1a, and the sheet 1b is double-fed together with the sheet 1a. Probability drops dramatically. Also, the separation roller 4
And the operation of driving the lifter 6 can be performed by one operation of driving the cam 8.

As shown in FIG. 6, after the conveyance is completed, the weight rollers 38a and 38b move toward the lower surface of the paper cassette 2 (downward in FIG. 6) by their own weight, and the paper is moved between the paper cassette 2 and the separation roller 4. When the sheet 1b exists, the sheet 1b is moved toward the lower surface of the sheet cassette 2. Therefore, the sheet 1b does not come into contact with the pick roller 3b when the sheet is not fed, and the sheet 1b is not erroneously conveyed when the sheet is not fed. After the conveyance of the sheet 1a, for example, the pick rollers 3a, 3b, and 3 are also used during printing to simplify the driving mechanism.
This is particularly effective for a printer in which c rotates.

In the above description, paper 1 is stored in paper cassette 2
Pick roller 3a as a means for pressing in the lower surface direction of
Since the weight rollers 38a and 38b having substantially the same diameters as those of the rollers 3b and 3c are used, the area of contact with the sheet 1 is larger than that of the pressing means of the sheet 1 by a bellows or a roller having a small curvature. But very few. Therefore, the present invention is particularly effective when the pick-up roller 3b side of the sheet 1 is a sheet conveying apparatus in which a printing screen is formed.

As shown in FIGS. 3 to 6, the moving amount of the weight rollers 38a and 38b due to their own weight is
Is smaller than the movement amount of the separation roller 3 when the sheet is not fed.
8a, 38b, paper cassette 2, and separation roller 38
a, 38b, the paper cassette 2, and the separation roller 4 do not come into contact with each other, so that the paper 1 is not damaged unnecessarily.

Embodiment 2 Hereinafter, a second embodiment of the present invention will be described. FIG. 7 is a configuration diagram of a weight roller according to Embodiment 2 of the present invention. In the figure, 41A,
41B is a roller member divided into two, and 42A and 42B are screws (coupling means) for mechanically coupling the roller members 41A and 41B. The other configuration is the same as that of the first embodiment, and a description thereof will be omitted.

As described above, since the weight roller 38 has a two-part structure, it can be easily put on and taken off. Further, since the screws 42A and 42B are fastened from the circumferential direction of the weight roller 38, the pick roller 3 divided into three parts as shown in FIG.
a, 3b, and 3c can be attached and detached. When there is a possibility that the cutouts of the roller members 41A and 41B may damage the sheet 1, a replenishing member (not shown) may be supplied so that the edges of the cutouts disappear. Furthermore, the weight roller 38 may be divided into a plurality of parts.

Embodiment 3 Hereinafter, a third embodiment of the present invention will be described. FIG. 8 is a configuration diagram of a weight roller according to Embodiment 3 of the present invention. In the figure, reference numeral 43 denotes a roller, and reference numeral 44 denotes a raised brush formed of fibers made of synthetic resin, rubber, or the like, and implanted on the roller 43. The other configuration is the same as that of the first embodiment, and a description thereof will be omitted.

As described above, the surface of the weight roller 38 is raised, and when the weight roller 38 comes into contact with the sheet 1, a wide contact surface of the weight roller 38 with the sheet 1 can be obtained. The contact load per area can be reduced, and it is possible to prevent the weight roller 38 from being damaged when it comes into contact with the surface of the paper 1. Embodiment 3
In the above, the example of the integral weight roller 38 is shown, but the same effect can be expected with the divided type weight roller 38 described in the second embodiment.

Embodiment 4 FIG. Hereinafter, a fourth embodiment of the present invention will be described. FIG. 9 is an explanatory diagram of sheet retraction according to Embodiment 4 of the present invention. The state of FIG. 9 is a state in which the lifter 6 is drive-controlled after the state of FIG. 6, that is, after the conveyance of the first sheet is completed, the lifter 6 is driven to move the sheet 1b to the state shown in FIG.
Is moved along the arrow d to abut on the pick roller 3b, and the pick roller 3b is driven to rotate in the direction opposite to the sheet take-out direction (the direction of arrow C in FIG. 9). In the fourth embodiment, the separation roller 4 is not shown in FIG.
Does not change from the position. The other configuration is the same as that of the first embodiment, and a description thereof will be omitted.

After the sheet feeding operation is completed, the lifter 6 and the separation roller 4 are moved downward in the drawing to drop the second sheet 1b onto the sheet tray 2 in the same manner as in the first embodiment. Picker 3b moves second sheet 1b with lifter 6
By driving the pick roller 3b in the direction (c direction) opposite to the transport direction, the second sheet 1b dropped on the sheet tray 2 can be pulled back to the sheet tray 2. It is preferable that a stopper is provided on the inner wall of the rear end of the sheet tray 2 to restrict the position where the sheet 1b is pulled back.

In the above description, the case where the present invention is applied to a device for separating and feeding paper is described, but it goes without saying that the present invention can be used for other devices for transporting a flexible body.

[0038]

According to the automatic paper feeder of the present invention, the separation roller and the paper are brought into contact with the pick roller during paper feeding, and the separation roller and the paper are separated from the pick roller when paper is not fed. The weight roller, which is formed to have substantially the same diameter as the pick roller and is loosely fitted on the shaft supporting the pick roller, moves toward the lower surface of the paper cassette by its own weight when paper is not fed. , Paper can be taken out without double feed and misfeed, and various types of paper having different characteristics can be handled without causing any trouble such as scratches on the surface of the paper.

The moving amount of the weight roller due to its own weight is as follows.
Since the distance is smaller than the moving distance of the separation roller, no contact pressure is applied carelessly to the sheet when the sheet is not fed, and no scratch or the like is generated on the sheet surface.

Further, since the weight roller is formed so as to be able to be divided in the radial direction of the shaft to be loosely fitted, the weight roller can be easily attached to and detached from the shaft.

Further, the control means drives the lifter to move the sheet to contact the pick roller after the first sheet is conveyed, and to rotate the pick roller in the direction opposite to the sheet take-out direction. Unnecessary paper can be pulled back to the paper tray, and double feeding and jamming of paper can be prevented.

[Brief description of the drawings]

FIG. 1 is a configuration diagram schematically showing an automatic sheet feeding device according to a first embodiment of the present invention.

FIG. 2 is a block diagram of a control mechanism of FIG. 1;

FIG. 3 is a sectional view showing an operation in an initial state of FIG. 1;

FIG. 4 is a cross-sectional view illustrating an operation in a paper feeding state of FIG. 1;

FIG. 5 is a cross-sectional view illustrating an operation in the transport state of FIG. 1;

FIG. 6 is a cross-sectional view showing an operation in a conveyance end state in FIG.

FIG. 7 is a configuration diagram of a weight roller according to Embodiment 2 of the present invention.

FIG. 8 is a configuration diagram of a weight roller according to Embodiment 3 of the present invention.

FIG. 9 is an explanatory diagram of sheet retraction according to Embodiment 4 of the present invention.

FIG. 10 is a cross-sectional view illustrating a conventional automatic sheet feeder.

[Explanation of symbols]

1 paper, 1a first sheet, 1b second sheet, 2 paper cassette, 3a, 3b, 3c pick roller, 4 separation roller, 6 lifter,
7 lever, 8 cam, 9 follower, 10
Spring, 11 Spring, 12 Pick roller gear, 13 Separation roller gear, 14
Torque limiter, 15 gears, 16 gears,
17 lever rotation axis, 18 lifter rotation axis,
22a, 22b feed roller, 23 feed roller biasing means, 38a, 38b weight roller

Claims (4)

[Claims] A pick roller for taking out the paper stored in the paper cassette; a separation roller which comes into contact with and separates from the pick roller to separate the paper taken out by the pick roller one by one; Separation roller driving means for moving toward and away from the roller, a lifter for moving the paper housed in the paper cassette to contact the pick roller, lifter driving means for driving the lifter, and separation roller driving means And a driving source for driving the lifter driving means, the separation roller driving means and the lifter driving means are controlled to contact the separation roller with the pick roller via the paper at the time of paper feeding, and At the time of paper feeding, the separation roller and control means for separating the paper from the pick roller, and the pickup roller is formed to have substantially the same diameter as the pick roller, and A weight roller loosely fitted on a shaft supporting the pick roller and moving toward the lower surface of the paper cassette under its own weight when paper is not fed; 2. The moving amount of the weight roller due to its own weight is smaller than the moving amount of the separation roller.
Automatic paper feeder as described. 3. The weight roller according to claim 1, wherein the weight roller is formed so as to be able to be divided in a radial direction of a shaft to which the weight roller is loosely fitted.
Automatic paper feeder as described. 4. The control means, after the conveyance of the first sheet is completed,
The automatic sheet feeding apparatus according to any one of claims 1 to 3, wherein the lifter is driven to move the sheet to make contact with the pick roller, and the pick roller is driven to rotate in a direction opposite to the sheet take-out direction. apparatus.