JP2849847B2 - Paper feeder - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device for separating and feeding stacked sheets one by one, and for example, for feeding paper or an original to a copying machine, a facsimile, a printer, or the like. It is used for.

2. Description of the Related Art In order to separate and feed sheets one by one, a separation roller that rolls and comes into contact with a first sheet of the fed sheet and a sliding roller that comes into contact with the separation roller and that passes through the second sheet and below by the frictional force. The configuration provided with a plate-like frictional body for blocking is widely used because it is simple, takes up little space, and has relatively good separation performance.

However, in the paper feeder provided with such a separating mechanism, it is difficult to secure the parallelism between the cylindrical surface of the separating roller and the plate-shaped friction body over the entire sheet width, and skew feeding is likely to occur. There was a point.

In addition, because of the simple configuration, it is easily affected by adjustment of the contact pressure between the separation roller and the plate-like frictional body, the surface condition of the frictional body, and the like, and double feed or non-feed may occur.

In order to solve such problems, for example,
In Japanese Patent No. 56062, Japanese Patent Publication No. 62-16902, etc., the plate-like friction body is pivotally supported in a plane parallel to the rotation axis of the separation roller so as to follow the cylindrical surface of the separation roller. .

Japanese Patent Application Laid-Open No. SHO 60-56746 discloses a device which is configured to be able to swing around an axis perpendicular to the direction in which the sheet travels.

[Problems to be Solved by the Invention] However, in the configuration of Japanese Patent Publication No. Sho 62-56062,
Although the plate-like friction member can always keep parallel to the cylindrical surface of the separation roller, the support shaft of the plate-like friction member is provided considerably upstream from the contact point between the separation roller and the friction member, Further, since the friction body is a flat plate, and the nip point of the registration roller pair is provided on an extension of the surface of the friction body, when the sheet enters, the friction body is separated from the separation roller almost in parallel with the contact, It is pointed out that there is no means for restricting the increase in the gap, and the blocking ability of the second sheet or less is inferior and the possibility of double feed is high.

Further, in the configuration of Japanese Patent Publication No. Sho 62-16902, although the effect that the friction body can be swung in a plane including the rotation axis of the separation roller and the contact line can be expected for the time being, the supporting portion of the friction body is required. It is pointed out that it is provided on the downstream side of the sheet advancing and has a configuration in which the sheet advancing side is widened, and is not suitable for the operation purpose of preventing the advancing of the second sheet and below.

Further, in the configuration disclosed in Japanese Patent Application Laid-Open No. 60-56746, the friction body does not swing in a plane including the rotation axis of the separation roller and the contact line, and is not easily adapted to the cylindrical surface of the separation roller.
There is a problem that the pressing force and the frictional force with respect to the sheet are hard to be uniform on the left and right sides of the sheet, and the sheet is easily skewed.

[Object of the Invention] The present invention has been made in view of the above-described problems in the related art, and the sheet pressing force of the plate-like frictional body to the separation roller is always kept uniform over the entire width of the roller. It is an object of the present invention to provide a sheet feeding device in which the skew feed is not performed, and the contact point between the separation roller and the friction member is always tight during the sheet feeding operation, and double feed is unlikely to occur.

[Means for Solving the Problems] A feeding roller comprising: a separation roller for feeding a sheet fed from a stacker; and a plate-shaped friction body pressed against the separation roller to separate the sheets one by one. In the paper device, a support member for supporting a central portion of the plate-like friction body at one end in a sheet feeding direction from a direction opposite to a pressing direction of the plate-like friction body is provided, and the plate-like friction body is provided with the support member. The sheet is supported by the support member such that both ends in a direction orthogonal to the sheet feeding direction are swingable with the support position of the central portion supported by the member as a fulcrum, and the pressure contact position with the separation roller is a fulcrum. This is achieved by oscillating both ends in the sheet feeding direction.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

The paper feeding apparatus of the present invention is applied to an electronic copying apparatus E as shown in FIG.

As shown in the drawing, the electronic copying apparatus E is provided with two paper feeding devices. The paper feeding device 10 controls the feeding of the original sheet, and the paper feeding device F performs the feeding of the copy sheet. Since both the sheet feeding devices 10 and F have basically the same configuration and operation, the sheet feeding device 10 will be described below.

The electronic copying apparatus E includes the paper feeding device 10 for feeding the original sheet and the paper feeding device F for feeding the copy sheet as described above, and is positioned on the platen B by the transport device C.
At the same time, a copy sheet is fed, a well-known copying process is performed, the used document is sent to a paper output tray S provided on the upper surface of the apparatus main body, and the copied sheet is sent to a copy tray or It is sent to a sorter or the like.

As shown in FIGS. 1 and 2, a sheet feeding device 10 includes a sheet stacker 11 for placing an original sheet, and a sheet stacker
A sheet guide plate 13 extends in the sheet feeding direction following the leading end of the sheet guide plate 11, and a kick is provided at a lower portion of the sheet guide plate 13, which is close to the sheet stacker 11 and partially cut out in a half-moon shape. A roller 12 is provided.

An upper guide plate 14 is provided above the kick roller 12.
However, the front end portion is provided with an angle of attack so as to receive the sheet. A part of the upper guide plate 14 is notched, and a weight 16 that rotates around the shaft 15 through the notch and presses the upper surface of the sheet is provided. The weight 16 has an arm portion 16a having elasticity and is urged counterclockwise in FIG. 2 around the shaft 15, and when the solenoid 17 is ON, it is pulled down clockwise in FIG. Apply a load to.

On the other hand, from below the sheet guide plate 13, there is provided a gate stopper 18 for aligning and stopping the front edge of the sheet when the sheet is inserted into the sheet stacker 11, and the gate stopper 18 is in the stop state when no power is supplied. When the solenoid 19 is energized, it rotates clockwise in FIG. 2 and is pulled down to the lower surface of the sheet guide plate 13.

At the position of the gate stopper 18, an empty sensor 20 is provided as shown in FIG.

A separation roller 21 for separating sheets one by one is provided alongside the kick roller 12, and a part of the outer peripheral cylindrical surface is exposed on the upper surface of the sheet guide plate 13 as shown in the figure. The surface of the separation roller is coated with, for example, a rubber-like material, and has high friction performance.

As shown in FIG. 3 showing the main part near the separation roller 21 in more detail, an upper guide plate is provided above the separation roller 21.
There is provided a rigid separating plate 35 hanging down from 14 and constituting a front separating means having an acute angle of attack upon receiving the leading edge of the sheet.

The rigid separating plate 35 is formed of a hard plate that is not deformed by the sheet feeding force. A first passage gap a for the sheet is provided between the lower end edge of the plate and the separation roller 21.

Further, on the back of the rigid separating plate 35, an elastic separating plate 36 made of an elastic material that is deformed by a sheet feeding force is adhered. Is provided. The first passage gap a and the second passage gap b have a relationship of a = b or a> b.

As shown in FIG. 3, a surface covering material 37 made of a material having a low coefficient of friction is adhered to the surface of the rigid separating plate 35 on the side of receiving the sheet. In the surface covering material 37, a step 37a is provided between the rigid separating plate 35 and the hem at the bottom, the first passage gap a is secured, and the sheet is closely adhered to the step 37a. Has been released to improve the separation performance.

Next, a friction pad 22 is provided as a plate-like frictional body that slides on the separation roller 21 and prevents passage of the second sheet or less. The friction pad 22 is made of, for example, rubber or a rubber-like material, and has a high friction performance with respect to a sheet surface, but is smaller than a friction coefficient of the surface of the separation roller 21.

From the contact point P between the friction pad 22 and the separation roller 21 in the sheet feeding direction, as shown in the drawing, it has an arc shape having a radius larger than the curvature radius of the separation roller 21, and the leading end in the sheet feeding direction has A protrusion 22a is formed. The side that receives the sheet from the point P is made flat.

On the other hand, as shown in FIG. 3, the friction pad 22 is held by a pad holder 23 as a friction body holder.

The pad holder 23 is a pressing spring as pressing means for pressing the friction pad 22 against the separation roller 21 from the back.
The pressing roller 24 is pressed in the direction of the separation roller 21. As shown in FIGS. 3 to 5, the contact point (actually a contact line in the sheet width direction) P in a stationary state.
And one support point Q at the end of the pad holder 23 on the sheet downstream side. Further, the pressing spring 24
Has a pressing position R between the two points P and Q,
As shown in FIG. 5, two pressing springs 24 are provided at symmetrical positions with respect to the bearing point Q.

On the other hand, as shown in FIGS. 3 and 4, support pins 23a, 23a are provided on the right and left ends of the pad holder 23 at the sheet advance upstream side, and the entire pad holder 23 is raised above the Q point side. When engaged, the upper guide plate 14 is configured to engage with the bent portion 14a. A projection 23b is also provided below the support point Q of the pad holder 13 so as to engage with the downstream upper guide plate 25 with a gap f therebetween.

On the downstream side of the separation roller 21, a downstream sheet guide plate 26 is provided.
Across the resist space 27, which is greatly bent
There are provided registration rollers 28 and 29 each including a pair of roller pairs for aligning the leading ends of the sheets and for taking the conveyance timing. A sheet guide 30 for guiding the sheet to the platen B of the copying machine E is provided at the exit side of the registration rollers 28 and 29.
Are arranged.

As shown in FIG. 6, the contact point between the registration rollers 28 and 29, that is, the nip point N for holding the sheet, is defined by the contact point P of the separation roller 21 and the protrusion 22a of the friction pad 22.
It is located above the extension of the line connecting the tip of.

In front of the registration rollers 28 and 29, a registration sensor 31 for detecting arrival of a sheet is provided.

 Next, the operation will be described.

The sheet is placed on the sheet stacker 11. At this time, the solenoid 19 is not energized yet and the gate stopper
Numeral 18 is flipped up and holds the leading edge of the sheet. Further, the solenoid 17 is also in the OFF state, and the weight 16 is at a position away from the seat.

Therefore, when the copying apparatus E is started by pressing a paper feed start button (not shown), the solenoid 17 is turned on, and the weight 16 contacts the sheet and presses it downward. Then, the kick roller 12 and the separation roller 21 slightly start rotating at the same time. However, the solenoid 19 is turned ON for the first time after a minute time element, and the gate stopper 18 stops the advance of the sheet to align the paper edge between the time elements. In the above operation, when the sheet is not replenished to the sheet stacker 11, an alarm is issued by the detection of the empty sensor 20, and the apparatus E does not start.

Then, the stacked sheets move forward as a whole in accordance with the rotation of the kick roller 12, come into contact with the rigid separating plate 35, and are sorted.

The surface of the rigid separating plate 35 is smooth and has a low friction coefficient.
Since the sheet is covered with 37, the tip of the sheet is smoothly handled without being caught on the surface, and since the whole is inclined, the sheet tip is also arranged diagonally, so that the close contact between the sheets is loosened. Further, the close contact between the sheets is further released at the step portion 38a, and a small number of sheets pass through the first passage gap a.

Further, these sheets are pressed against the elastic separating plate 36, and the minimum number of sheets pass through the second passage gap b smaller than the first passage gap a.

The sheet then enters between the separation roller 21 and the friction pad 22.

The friction coefficient of the friction pad 22 is larger than that of the sheets,
Since two sheets have entered so far, the upper sheet in the figure stops on the friction pad 22 side, and the separation roller 21 side. Sheet is sent as it is.

Further, when only one sheet is sent, the sheet is sent as it is because the lower surface of the sheet receives a stronger frictional force.

In the above operation, the pad holder 23 is pivotally supported at one point Q, and the pressing springs 24 are provided at symmetrical positions with respect to the pivot point Q.
3. As a result, the friction pad 22 has a good balance in the sheet width direction, there is no bias in the contact pressure with the separation roller 21, and the sheet is always fed while being pressed with a uniform pressure, so that skew feeding or the like does not occur.

The sheet separated by the separation roller 21 and the friction pad 22 travels along the curved lower surface of the friction pad 22, and the front end of the sheet is formed by a downstream sheet guide plate 26 that is largely bent downward. After being once lowered into the space 27, it is raised again along the downstream sheet guide plate 26 and is nipped by the registration rollers 28 and 29. Then, immediately before that, the registration sensor 31 issues a detection signal of the paper edge. The kick roller 12 and the separation roller 21 are stopped by this detection signal. Then, after a short time, the registration rollers 28 and 29 start to rotate. Usually at this point,
The trailing edge of the sheet is still captured at the contact point P, and the tension gradually increases as the registration rollers 28 and 29 rotate.

However, as shown in FIG. 6, the nip point N between the registration rollers 28 and 29 is
Since the pad holder 23 is deviated upward from the extension of the straight line connecting the contact point a and the pad holder 23, with the contact point P as a fulcrum, the support point Q side is lifted upward, and the contact point P It moves to the upstream side of the paper feed, and more strictly prevents the subsequent paper from entering, thereby completely preventing double feed.

The sheet fed by the registration rollers 28 and 29
The sheet is conveyed to the conveying device C via the sheet guide 30, is located on the platen B of the copying device E, is subjected to a copying process, and is again discharged to the sheet discharge tray S by the action of the conveying device C.

[Brief description of the drawings]

1 to 6 show an embodiment of the present invention. FIG. 1 is an overall view of an electronic copying apparatus having a paper feeder, and FIG.
FIG. 3 is a longitudinal sectional view of the sheet feeding device, FIG. 3 is an enlarged view of a main part in the vicinity of a separation roller, FIG. 4 is a perspective view in the vicinity of a friction body holder, and FIG. 5 is A in FIG. FIG. 6 is a view for explaining the operation near the separation roller. 10 Paper feeder 11 Sheet stacker 12 Kick roller 13 Sheet guide plate 14 Upper guide plate, 14a Bending portion 16 Weight 17 Solenoid 18 Gate stopper 19 Solenoid 21 Separation roller 22 Friction pad (plate-like friction body) 22a Projection P point Contact point between separation roller and friction pad 23 Pad holder (friction body holder) 23a Support pin , 23b Projecting portion Q point Supporting point of pad holder 24 Pressing spring (pressing means) R point Pressing position of pressing spring in pad holder 27 Register space 28, 29 Register roller N Point: Nip point of resist roller 35: Rigid separating plate 36: Elastic separating plate 37: Surface coating material, 37a: Stepped portion E: Electronic copying device F: Paper feeding device (for copy sheet) B …… Platen S …… Discharge tray C …… Conveyer

Claims (4)

(57) [Claims] 1. A sheet feeding device comprising: a separation roller for feeding a sheet fed from a stacker; and a plate-shaped friction member pressed against the separation roller to separate the sheets one by one. A support member is provided for supporting a central portion of the plate-shaped friction body at one end in a sheet feeding direction from a direction opposite to a pressing direction of the plate-shaped friction body. The plate-shaped friction body is supported by the support member. Both ends in a direction perpendicular to the sheet feeding direction with the support position of the central portion as a fulcrum are supported by the support member so as to be swingable, and both ends in the sheet feeding direction with a pressure contact position with the separation roller as a fulcrum. A sheet feeding device provided so as to swing the section. 2. The sheet feeding device according to claim 1, wherein a center portion of the plate-like friction member supported by the support means at one end in a sheet feeding direction has a pivot structure. 3. A pressing means for pressing said plate-like frictional body against said separating roller, said pressing means comprising a pressing position of said separation roller in a sheet feeding direction of said plate-like frictional body and said supporting member. 2. The sheet feeding device according to claim 1, wherein a space between the sheet feeding device and the supporting position is pressed. 4. A registration roller for transporting a sheet passing between said separating roller and said plate-like frictional body, said sheet-like frictional body being moved in a direction opposite to said pressing direction by said sheet being transported by said transporting means. 2. The sheet feeding device according to claim 1, wherein the sheet is conveyed by the registration roller, and the pressure contact position between the separation roller and the friction member is moved toward a sheet entry side.