JPH03264437A - Sheet feed device - Google Patents

Abstract

PURPOSE:To obtain a uniform pressing force over entire roller width, and eliminate the feed of a skewed sheet and the double feed of a sheet by providing a support for a sheet friction body at the downstream side of sheet advance, and setting a separation roller pressing position at a mid-point between the point of contact of the friction body with a separation roller and the downstream side of sheet advance. CONSTITUTION:A friction pad 22 retained with a pad holder 23 comes in contact with a separation roller 21 at a point P, and is retained at one point Q in the downstream of sheet advance. Furthermore, the pad 22 is made effective under pressure at a midpoint R between points P and Q with two pressure springs 24 symmetrically positioned right and left about the point Q. Also, resist rollers 28 and 29 are so arranged that the nips N thereof are located above an extension line between the contact point P and the projecting part of the friction pad 22a. According to the aforesaid construction, the pressing force of the friction pad 22 is uniform over the entire width of the separation roller 21 and, therefore, a sheet is not fed in a skewed condition. In addition, the contact point P shifts to the upstream side of sheet feeding, according to the tension of a sheet, thereby enabling the effective prevention of double sheet feeding.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a paper feeding device that separates and feeds stacked sheets one by one, and is useful for feeding paper, manuscripts, etc. to copying machines, facsimile machines, printers, etc. It is used for.

[Prior Art] In order to separate and feed sheets one by one, a separating roller is used which rolls into contact with the first sheet of the fed out sheets, and a separating roller is in sliding contact with this separating roller, and its friction force prevents the second sheet and subsequent sheets from passing. A structure equipped with a plate-shaped friction body for blocking is often used because it is simple, does not take up much space, and has relatively good separation performance.

However, in a paper feeding device equipped with such a separation mechanism, it is difficult to ensure parallelism between the cylindrical surface of the separation roller and the plate-shaped friction body between the middle and the end of the sheet, and skew feeding is likely to occur. There was a problem.

In addition, because of its simple structure, it is easily affected by the adjustment of the contact pressure between the separation roller and the plate-shaped friction body, the surface condition of the friction body, etc., and double feeding or non-feeding may occur. .

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

Further, as a device configured to be swingable around an axis perpendicular to the direction of travel of the sheet, there is one disclosed in Japanese Patent Application Laid-Open No. 60-56746.

[Problems to be Solved by the Invention] However, in the configuration of Japanese Patent Publication No. 62-56062, although the plate-shaped friction body can always be kept parallel to the cylindrical surface of the separation roller, the plate-shaped friction body cannot be supported. The shaft is provided considerably upstream from the point of contact between the separation roller and the friction body, the friction body is a flat plate, and the nip point of the pair of registration rollers is provided on the extension line of the surface of the friction body. Therefore, when the sheet enters, the rs rubbing body separates from the separation roller almost parallel to the time of contact, and there is no means to restrict the increase in the gap, and the blocking ability for the second sheet and below is poor, leading to the possibility of double feeding. It is pointed out that the problem is that the

In addition, in the configuration of Japanese Patent Publication No. 62-16902, although the effect of the friction body being able to swing in a plane that includes the rotational axis of the separation roller and the contact line can be expected, the support part of the friction body is It is installed on the downstream side of the sheet progression.
It has been pointed out that the structure is such that the sheet entry side is widened, and it is not suitable for the purpose of operation of preventing the advance of the second sheet and the subsequent sheets.

Furthermore, in the configuration according to Japanese Patent Application Laid-Open No. 60-56746, the friction body does not swing within a plane that includes the rotation axis of the separation roller and the contact line, and the friction body becomes familiar with the cylindrical surface of the separation roller.
Although the pressing force and frictional force against the sheet are uniform on the left and right sides of the sheet, there is a problem that skew feeding is likely to occur.

[Object of the Invention] The present invention has been developed in view of the problems in the conventional technology as described above, and it is possible to maintain the pressing force of the plate-shaped friction body against the separation roller uniformly over the entire width of the roller, thereby preventing the sheet from being damaged. There is no skew feeding, and the contact point between the separation roller and the friction body is always tightly tightened during paper feeding.
The purpose is to provide a paper feeding device in which double feeding is less likely to occur.

[Means for Solving the Problems] The above object is to include a pressing means for pressing a plate-shaped friction body against a roller, and to set a pressing position of the pressing unit on the plate-shaped friction body at a contact point with the separation roller. The plate-shaped r! A supporting portion of the J rubbing body opposing the pressing means is pivotably pivoted in a loss direction in which the sheet advances to a point near the center in the sheet width direction further downstream from the pressing position of the pressing means. One supporting and pressing means is disposed at symmetrical positions across the support portion of the plate-like friction body, and the pressure means are arranged on the downstream side of the plate-shaped friction body from the point of contact with the separating roller. A curved protrusion is formed on the separation roller side, and when the sheet is pulled by the registration roller, the front protrusion is pressed by the sheet and serves as a contact point between the plate-like RS rubbing body and the separation roller. This is achieved by a paper feeding device that generates a moment that opposes the moment caused by the pressing means and levitates the support portion side of the plate-shaped friction body.

[Operation] Usually, a plurality of sheets are fed out from the sheet stacker by the feeding means. These sheets then enter the contact portion between the separation roller and the plate-like fs#liI body.

The first sheet in contact with the separation roller advances as it is due to the feeding force of the roller, but the second and subsequent sheets are held back by the frictional force of the plate-shaped friction body and are prevented from advancing.

During the operation, the plate-shaped gI rubbing body moves approximately at the center part 1 in the middle direction.
Since the pressing means for pressing the friction body against the separation roller has pressing positions symmetrically across the supporting part, the plate-shaped gllllF body is always evenly applied to the surface of the separation roller. It makes contact with a certain amount of contact pressure, and exerts an even and uniform pressing force on the sheet, so there is no skew feeding.

When the leading edge of the sheet is gripped by the registration roller, the sheet is tensioned against the separation roller, and this tension presses the protrusion formed at the end of the plate-shaped friction body in the sheet advancing direction. The pressing force exerts a moment on the friction body that is opposite to the moment exerted on the plate-shaped friction body by the pressing means using the point of contact with the separation roller as a fulcrum, and the friction body is lifted up on the support side and floated, and vice versa. Since the point of contact with the separation roller is moved upstream to reduce the angle of attack of the sheet, the second and subsequent sheets are blocked and new sheets are prevented from entering.

[Example] Hereinafter, one embodiment of the present invention will be described based on the drawings.

The paper feeding device of this embodiment is applied to an electronic copying machine E, as shown in FIG.

As shown in the figure, the electronic copying apparatus E is provided with paper feed devices at two locations. Of these, the paper feeder 10 is in charge of feeding original sheets, and the paper feeder F is in charge of feeding copy paper.Since both paper feeders 10 and F have basically the same configuration and operation, the following will be explained below. The paper feeding device 10 will now be described.

As described above, the electronic copying device E includes the paper feeding device 10 that feeds original sheets and the paper feeding device F that feeds copy sheets, and is oriented on the platen B by the feeding device C.
At the same time, copy sheets are fed and a well-known copying process is carried out, and the used originals are transferred to the output tray S provided on the top of the main body of the device, and the copied sheets are transferred from the output port (not shown) to the copy tray or Sent to a sorter, etc.

As shown in FIGS. 1 and 2, the paper feeding device 10 includes a sheet stacker 11 on which original sheets are placed, and a sheet guide plate 13 following the tip of the sheet stacker 11 in the paper feeding direction.
is extended, and at the bottom of the sheet guide plate 13,
A kick roller 12 having a half-moon cutout is provided adjacent to the sheet stacker 11.

Additionally, an upper guide plate 1 is provided above the kick roller 12.
4 is provided with an angle of attack at the tip so as to receive the sheet. A portion of the upper guide plate 14 is cut out, and a weight 16 is provided through the cutout portion to rotate around a shaft 15 and press the upper surface of the seat.

This weight 16 has an elastic arm portion 16a and is biased counterclockwise in FIG. 2 around the shaft 15. When the solenoid 17 is ON, it is pulled down clockwise in the figure, and the seat is seated. Add a load to.

On the other hand, a gate stopper 18 is provided from below the sheet guide plate 13 to align and stop the front edges of sheets when they are inserted into the sheet stacker 11. It is energized to a stop state, and 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.

An empty sensor 20 is provided at the position of the gate stopper 18 as shown in FIG.

A separation roller 21 that separates sheets one by one is disposed alongside the kick roller 12, and a portion of its outer cylindrical surface is exposed on the upper surface of the sheet guide plate 13 as shown. The surface of this separation roller is coated with, for example, a rubber-like material, giving it high frictional performance.

As shown in FIG. 3, which shows the main parts near the separation roller 21 in more detail, the separation roller 21 has an acute angle of attack that hangs down from the upper guide plate 14 and receives the leading edge of the sheet. A rigid separating plate 35 is provided which acts as a pre-sorting means.

This rigid separating plate 35 is made of a hard plate that does not deform due to the force of feeding out the sheet, and there is a space between its lower edge and the separation roller 21 during the first passage of the sheet 1ie! A is provided.

Furthermore, an elastic separating plate 36 made of an elastic material that is deformed by the sheet feeding force is attached to the back surface of the rigid separating plate 35, and between the lower edge of the elastic separating plate 36 and the separating roller 21, a second sheet There are displays during the passage. The first passage gap a and the second passage gap have a relationship of a=b or a>b.

Further, as shown in FIG. 3, a surface covering material 37 made of a material with a low gI friction coefficient is adhered to the surface of the rigid handling plate 35 on the side facing the sheet. This surface covering material 37 has a stepped portion 37 between it and the rigid handling plate 35 at its bottom portion.
a is provided to ensure the first passage gap a, and at the stepped portion 37a, the sheets are brought out of close contact with each other to improve separation performance.

Next, a friction pad 22 is provided as a plate-shaped R1 friction body that slides on the separation roller 21 and prevents the passage of the second sheet and subsequent sheets. This III scrubbing pad 22 is made of rubber or rubber-like material, for example, and has a high rstl against the seat surface. However, the friction coefficient is smaller than the 19 friction coefficient of the surface of the separation roller 21.

As shown in the figure, the area from the contact point P between the friction pad 22 and the separation roller 21 in the paper feeding direction has an arc shape having a radius larger than the radius of curvature of the separation roller 21.
A protrusion 22a is formed at the leading end in the paper feeding direction. The side facing the sheet from the point P is flat.

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

The pad holder 23 is pressed from the back toward the separating roller 21 by a pressing spring 24 serving as a pressing means for pressing the pad 22 against the separating roller 21. As shown in FIGS. 3 to 5, in the stationary state, the contact point is actually a contact line in the width direction of the sheet>P, and a point on the downstream end of the pad holder 23 where the sheet advances. It is supported at the bearing point Q. Furthermore, the pressing spring 24 has a pressing position R between the two points P and Q, and as shown in FIG. ing.

On the other hand, as shown in FIGS. 3 and 4, at the upstream end of the pad holder 23, there are support bins 23a, 2
3a is protruded, and when the entire bud holder 23 is lifted up on the Q point side, the bent portion 14a of the upper guide plate 14
is configured to engage. Note that a protrusion 23b is also provided below the support point Q of the pad holder 13, and is configured 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 2 is provided.
Registration rollers 28 and 29 consist of a pair of rollers for aligning the leading edge of the sheet and timing the conveyance by separating the registration space 27 provided by bending the sheet greatly.
is provided.

A sheet guide 30 is provided on the exit side of the registration rollers 28 and 29 to guide the sheet to the platen B of the copying device fH.

The point of contact between the registration rollers 28 and 29, that is, the nip point N at which the sheet is gripped, is a line connecting the contact point P of the separation roller 21 and the tip of the protrusion 22a of the friction pad 22, as shown in FIG. It is located above the extension of

A registration sensor 31 is provided in front of the registration rollers 28 and 29 to detect the arrival of a sheet.

Next, the effect will be explained.

A sheet is placed on the sheet stacker 11. At this time, the solenoid 19 is not yet energized, and the gate stopper 18 is flipped upward and holds the front edge of the sheet. Further, the solenoid 17 is also turned off, and the weight 16 is located away from the seat.

Then, press the paper feed start button (not shown) to start copying machine E.
When started, the solenoid 17 is turned on and the weight 16 comes into contact with the seat and presses it downward.

After a while, the kick roller 12 and the separation roller 21 start rotating at the same time. However, the solenoid 19 is only turned on after a very small time interval, and the gate stopper 18 prevents the sheet from advancing in order to align the paper edge between the time intervals. In addition, in the above operation, when the sheet stacker 11 is not replenished with sheets, an alarm is issued by detection by the empty sensor 20, and the apparatus E
will not start.

The stacked sheets then move forward in their entirety as the kick roller 12 rotates, and come into contact with the rigid sorting plate 35 and are tidyed up.

Although the surface of the rigid handling plate 35 is smooth and covered with a surface coating material 37 having a low coefficient of friction #II, the tip of the sheet can be handled smoothly without getting caught on the surface, and since the entire surface is inclined, the sheet The tips are also aligned diagonally, loosening the adhesion between the sheets. Further, the adhesion between the sheets is further loosened at the stepped portion 37a, and a small number of sheets pass through the first passage gap a.

Further, these sheets are pressed against an elastic separating plate 36, and a second passage gap 1i smaller than the first passage gap a is formed.
ll! The minimum number of sheets passes through b.

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

The am coefficient of the friction pad 22 is larger than that of each sheet.
Since the surface of the separation roller 21 is made smaller than that of the surface of the separation roller 21, if two sheets have entered so far, the upper sheet in the figure will remain on the friction pad 22 side and will be on the separation roller 21 side. The sheets will be sent as they are.

Further, when only one sheet is fed, the lower surface of the sheet receives a stronger frictional force, so that the sheet is fed out as it is.

In the above operation, the pad holder 23 is pivoted at one point Q, and the pressure springs 24 are provided at symmetrical positions across the pivot point Q, so the pad holder 23 and, by extension, the friction pad 22 are Since the direction is well balanced, the contact pressure with the separation roller 21 is not biased, and the sheet is always fed while being pressed with uniform pressure, skew feeding does not occur.

The sheet separated into one sheet 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 sharply bent downward. After it once descends into the registration space 27, it rises again along the downstream sheet guide plate 26 and is nipped by the registration rollers 28 and 29. Immediately before that, the registration sensor 31 issues a paper edge detection signal. This detection signal causes the minute kick roller 12 and the separation roller 21 to stop.

Then, after a few more hours, the registration roller 28.29
begins to rotate 0 Normally at this point the trailing edge of the sheet is still captured at the contact point P and gradually tightens y1 as the registration rollers 28, 29 rotate.

However, the nip point N of the registration rollers 28 and 29 is the 6th
As shown in the figure, the pad holder 23 deviates upward from the extension of the straight line connecting the contact point P and the protrusion 22a of the friction pad 22, but due to the tension of the seat, the pad holder 23 moves the contact point P The support point Q side is lifted upward as a fulcrum, and the contact point P is also moved to the side above the paper feed 8, which further strictly prevents the subsequent next group from entering and completely prevents double feeding.

The sheet fed by the two registration rollers 28 is delivered to the conveying device C via the sheet guide 30, positioned on the platen B of the copying device E, and subjected to copying processing.
The paper is again discharged onto the paper discharge tray S by the action of the conveyance device C.

[Effects of the Invention] According to the paper feeding device according to the present invention, the pressing position of the pressing means for pressing the plate-shaped fjItlI body against the separation roller can be swung in the sheet advancing cross direction at a point near the center of the sheet. the plate-shaped friction body is able to float on said support when the plate-shaped friction body is subjected to a moment opposite to the moment received by the contact point with the separating roller; A protrusion curved toward the separation roller is formed on the downstream side of the contact point of the plate-shaped friction body with the separation roller, and the pressing means is positioned at a symmetrical position across the supporting portion of the plate-shaped friction body. Since the structure is such that one of each is arranged on the separation roller, the pressing force of the plate-shaped girder against the separation roller is always balanced on the left and right sides at the roller kanayama, and there is no bias in the pressing force against the sheet, causing skew feeding. do not.

Furthermore, during the sheet feeding operation, the gap between the separation roller on the entrance side and the plate-shaped friction body becomes narrower, thereby restricting the intrusion of subsequent sheets and preventing double feeding from occurring.

[Brief explanation of drawings]

1 to 6 show an embodiment of the present invention, in which FIG. 1 is an overall view of an electronic copying machine equipped with a paper feeding device,
The figure is a longitudinal cross-sectional view of the paper feeding device, Figure 3 is an enlarged view of the main parts near the separation roller, Figure 4 is a perspective view of the vicinity of the friction body holder, and Figure 5 is A of Figure 4. The arrow view and FIG. 6 are explanatory views of the action in the vicinity of the separation roller. 10 Paper feeding device 11 Sheet stacker 12 Kick roller 13 Sheet guide plate 14 Upper guide plate 14a Bent part 16 Weight 7 8 9 1 2 2a 9 points 3 3a 9 points 4 R point solenoid gate stopper solenoid separation roller friction pad (plate friction Contact point between the protruding part separating roller and the friction pad Pad holder (friction body holder) Support pin 23b Support point of the protruding part pad holder Pressing spring (pressing means) Pressing position of the pressing spring in the pad holder Paper feeding device (for sheets) Platen output tray conveyor device

Claims (5)

[Claims] (1) a separation roller that contacts the first sheet of the sheets fed out from the sheet stacker, and a separation roller that is in contact with the separation roller;
A sheet feeding device comprising a plate-shaped friction body that prevents passage of a second sheet and subsequent sheets by contact friction force, further comprising a pressing means for pressing the plate-shaped friction body against the separation roller, the pressing unit A pressing position on the plate-shaped friction body is provided on the sheet advancing downstream side of the point of contact with the separation roller, and a support portion opposing the pressing means of the plate-shaped friction body is provided at the pressing position of the pressing unit. A sheet feeding device characterized in that the plate-shaped friction body is provided at a point substantially toward the center in the width direction of the sheet on the downstream side of the traveling direction, and the plate-shaped friction body is pivotally supported to be swingable in a direction intersecting the traveling direction of the sheet. (2) The paper feeding device according to claim 1, wherein the support portion of the plate-shaped friction body has a pivot structure. (3) When the plate-shaped friction body receives a moment opposed to a moment received around the contact point with the separation roller by the pressing means, the plate-shaped friction body can float on the support portion. The paper feeding device according to claim 1 or 2, characterized in that: (4) A protrusion curved toward the separation roller is formed on the downstream side of the plate-shaped friction body from the point of contact with the separation roller, and a pair of registration rollers is provided, so that the sheet is pulled by the registration roller. At this time, the sheet presses the protrusion, generates a moment around the contact point between the plate-shaped friction body and the separation roller that counteracts the moment caused by the pressing means, and levitates the support side of the plate-shaped friction body. 4. A sheet feeding device according to claim 1, wherein the sheet feeding device is arranged so that the sheet entrance side is close to the separation roller side. (5) The paper feeding device according to any one of claims 1 to 4, wherein the pressing means are arranged at symmetrical positions across the supporting portion of the plate-shaped friction body.