JPH02178135A - Paper feeder - Google Patents

Abstract

PURPOSE:To make improvements in a sheet separative property by supporting a pad body of a separating means on a feeder frame free of rocking motion at a pad body rear end at a distance from a pressing part between the pad body and a paper feed roller to the paper feeding downstream side. CONSTITUTION:Each sheet delivered out of a stacker along a sheet guide plate 31 by action of a delivery means is entered into a separating means 40, and it acts so as to push a pad body 45 open against an energizing spring 50. However, even if a pressing point P between the pad body 45 pushed open and a paper feed roller 41 shifts to the downstream side of paper feeding, a support part 51 by a feeder frame 48 of the pad body 45 is installed in a position distant from the paper feeding downstream side, so that arm length (from P point to point 51) of rock motion out of the rocking part 51 decreases, whereby energizing force by the energizing spring 50 is relatively increased, thus an accurate separation action is securable. Thus, paper feeding failure and double feeding are surely preventable.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a paper feeding device that separates original sheets one by one and feeds them to an image forming device such as an electronic copying device, a printing device, etc. .

[Prior Art] A stacker for stacking and accommodating sheets, a feeding device for feeding the sheet against the top or bottom sheet of the sheets stored in the stacker, and a feeding device provided on the downstream side of the feeding device in the sheet feeding direction. a separating means comprising a paper feeding rotary body that rotates in the sheet feeding direction, a pad body that presses against the paper feeding rotary body to prevent double feeding of sheets, and a biasing means that presses the paper feeding rotary body; Conventionally, in a paper feeding device that feeds originals and other sheets one by one to an image forming device such as an electronic copying device, or a printing device such as a printing press, etc., conventionally, as shown in FIGS. 11 and 12, The swing support point r of the pad body 101 on the device frame is
It was provided on the upstream side in the paper feeding direction from the pressure contact point p between the paper feeding rotary body 102 and the paper feeding rotating body 102 .

[Problem U to be Solved by the Invention] However, as described above, the swing support point r of the pad body 101 on the device frame is located on the upstream side in the paper feeding direction from the pressure contact point p between the pad body 101 and the paper feed rotary body 102. As is clear from the above figures, the sheet fed from the feeding means acts to spread the pad body 101, and as the sheet advances, it swings with the pressure contact point p. The distance MS from the fulcrum r becomes larger, and the rotational force that tries to spread the pad body 101 increases, which acts in the direction of deteriorating the separation performance.

As mentioned above, if the pressing force of the urging means 103 is increased in order to prevent the feeding of multiple sheets, so-called double feeding, due to deterioration in separation performance, the feeding of the sheets will be blocked, and so-called non-feeding will likely occur. Furthermore, there was a problem in that the rotational power of the paper feeding rotary body 102 had to be increased unnecessarily.

[Purpose of the Invention] The present invention has been made in view of the problems in the conventional technology, and is an easy technology that simply changes the relative positions of several supporting parts that hold the pad body. It is an object of the present invention to provide a paper feeding device that not only improves sheet separation performance and prevents double feeding and non-feeding, but also reduces the driving power of a paper feeding rotary member.

[Means for Solving the Problems] In order to achieve the above object, the present invention includes a stacker for stacking and accommodating sheets, and a feeder for feeding the sheets against the top or bottom sheet of the sheets stored in the stacker. a sheet feed rotary body that is provided downstream of the feeding means in the sheet feeding direction and rotates in the sheet feeding direction;
In the paper feeding device, the pad body is provided with a separating means comprising a pad body that presses against the paper feeding rotary body to prevent double feeding of sheets, and a biasing means that presses the paper feeding rotary body, the pad body is The paper is held at three points: a pressure contact part with the paper rotating body, a biasing force part of the biasing means, and a support part by the device frame, and the support part by the device frame is supported by the pad body and the paper feeding rotary body. The pad body is swingably supported at its rear end, which is spaced downstream in the paper feeding direction from the press-contact portion.

[Function] The sheet inserted into the stacker is sent out downstream by the action of the feeding means.

The sheet that has entered the separating means acts to push the pad body open, but even if the sheet is pushed open and the pressure contact point between the pad body and the paper feed rotating body moves to the paper feed downstream side, the device of the pad body Since the part supported by the frame is provided on the downstream side in the paper feeding direction and further apart from tfLz, the length of the swinging arm from the swinging part is reduced, and the urging force by the urging means is relatively increased. Therefore, even if a plurality of sheets enter the separating means, the separation effect is reliably performed.

Since the urging force of the urging means acts in a direction that gradually increases, there is no need for the urging means to be strong from the beginning, and therefore there is no need to unnecessarily increase the power of the paper feeding rotary body. .

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

In this embodiment, as shown in FIG. 4, a paper feeder 20 in the electronic copying apparatus 1 that supplies original documents for copying one by one will be described.

As shown in FIG. 4, the electronic copying device 1 is provided with a platen 3 on the top surface of the main body 2 for placing originals, and a paper feed cassette 4 for supplying copy sheets on one side. There is a paper output tray 5 on the side for receiving copied copy sheets.
is installed.

On the other hand, inside the apparatus main body 2, an optical system consisting of an exposure lamp 6 and a group of mirrors 7 that move back and forth while irradiating the document from the lower surface of the platen 3, and a lens block 8 for variable magnification form a latent image. A photosensitive drum 9, a developing device 10 that applies toner to this electrostatic latent image and develops it, and a transfer device 11 that transfers this toner image onto a copy sheet. A fixing device 12 for fixing the transferred toner image and the like are housed.

As shown in FIG.
There is a sheet stacker 22 for placing original sheets on the upper part, a paper feeding section 30 for feeding sheets one by one, conveying the original sheets onto the platen 3 of the apparatus main body 2 and placing them there, and further processing after the copying process is completed. It consists of a conveying section 24 that discharges the paper backward and discharges the paper to a discharge stacker 23.

As shown in FIG.
A sheet guide plate 31 extends in the paper feeding direction following the tip of the sheet guide plate 31. At the bottom of the sheet guide plate 31, near the sheet stacker 22, there is provided a half-moon cutout as a feeding means. A kick roller 32 is provided. Further, an upper guide plate 33 is provided above the kick roller 32 with an angle of attack at its tip so as to receive the sheet. A portion of the upper guide plate 33 is cut out, and a weight 35 is provided through the cutout portion to rotate around a shaft 34 and press the upper surface of the seat. This weight 35 has an elastic arm portion 35a and is biased clockwise in FIG. Add a load to.

On the other hand, a gate stopper 37 is provided from below the sheet guide plate 31 to align and stop the front edges of sheets when they are inserted into the sheet stacker 22. When the sheet is not energized, the gate stopper 37 is in the stopped state. is energized, and when the solenoid 38 is energized, the 112th I
is rotated counterclockwise and pulled down to the lower surface of the sheet guide plate 31.

Alongside the kick roller 32, a separating roller 41, which is a sheet feeding rotary body constituting the separating means 40, is arranged, and a part of its outer cylindrical surface is connected to the sheet guide plate 31 as shown in the figure.
exposed on the top surface.

As shown in FIG. 2, which shows the essential parts near the separating roller 41 in more detail, above the separating roller 41 hangs down from the stationary part of the main body frame 21, and receives the leading edge of the sheet at an acute angle of attack. A rigid handling plate 4 which is a first handling means having
2 is provided.

The rigid separating plate 42 is made of a hard plate that does not deform due to the sheet feeding force, and a first sheet passage gap a is provided between its lower edge and the separating roller 41.

Further, an elastic separating plate 43, which is a second separating means and is made of an elastic material that deforms due to the sheet feeding force, is attached to the back surface of the rigid separating plate 42, and the lower edge of the elastic separating plate 43 is connected to the separating roller 41. A second passage gap for the sheet is provided in between.

The first passage gap a and the second passage gap a are a=b or a>b The relationship between

According to careful experimental results, the angle of attack a formed by the above-mentioned two-handling plates 42 and 43 with the upper surface of the seat is approximately g = 50''57', but of course it is not limited to this value. .

Next, a pad body 45, which is another member constituting the separating means 40, is disposed on the downstream side of both the separating plates 42, 43 in the paper feeding direction in close proximity to the separating plates 42, 43.

As shown in FIG. 2, this pad body 45 is
1 and a pad holder 47 for holding this pad 46.

As shown in FIG. 2, the pad 46 is in pressure contact with the cylindrical outer circumferential surface of the separating roller 41, and a line connecting the contact point P, which is the pressed part, and the center of the separating roller 41 is perpendicular to the surface of the sheet. Although it has been experimentally determined that the angle γ formed with the line is optimal in the range of 9° to 16°, it goes without saying that the angle γ is not limited to this value.

The area from the contact point P on the lower surface of the pad 46 in the paper feeding direction has an arc shape having a radius of curvature larger than the radius of curvature of the separating roller 41, as shown in the figure.
A protrusion 46a is formed at the leading end in the paper feeding direction. The side facing the sheet from the point P has a flat portion, so the angle of attack is also an angle T. The pad 46 is made of a rubber-like soft material, such as urethane rubber with a hardness of 80 degrees, and is harder than the handling roller 41 and has a lower coefficient of friction, but has a coefficient of friction larger than that between the sheets. It is done like this.

On the other hand, the pad holder 47 holding the pad 46 is
As shown in the figure, the engaging portion 51, which is a part supported by the device frame at the rear end, is supported by the support plate 48 of the main body frame 21, and is pressed in the direction of the sorting roller 41 by a biasing spring 50, which is biasing means. ing.

That is, the pad body 45 as a whole is supported by three points: the point P, the force applying point Q which is the urging force applying part of the urging spring 50, and the engagement #5t.

In the biasing direction of the biasing spring 50, the pad holder 47
is arranged so as to be biased clockwise in FIG. As shown in the figure, the engagement portion 51 supported by the support plate 48 is provided with a slight backlash 51a.

Further, the engaging portion 51 is provided further downstream of the paper feeding point than the force applying point Q, and is spaced a distance ms from the point P.
It is located in

Further, as shown in the figure, an attack angle β is provided on the side of the pad 46 that faces the seat.

The angle of attack β is optimally between 15° and 22°, but is not limited to this value.

As mentioned above, each angle of attack a, β, γ is a〉β〉T The relationship between

On the downstream side of the separation means 40, there are registration rollers 61 and 62 consisting of a pair of rollers that deliver the sheet to the conveying section 24 across a registration space 60 provided by bending the sheet guide plate 31 considerably. is provided. The sheet is placed on the exit side of the registration rollers 61 and 62 by the conveying section 2.
4 is provided.

The contact point of both registration rollers 61 and 62, that is, the nip point R where the sheet is held in their mouths, is located above the tangential direction A of the curved portion of the pad 46, as shown in FIGS. 8 and 9. .

In addition, along the sheet guide plate 31, the gate stopper 3
An empty sensor 65 that detects the presence or absence of sheets in the sheet stacker 22 is provided upstream of the sheet stacker 7, and a registration sensor 66 that detects the arrival side of the sheet is provided in front of the registration rollers 61 and 62. .

Next, the effect will be explained. In addition, in explaining the operation, in addition to Figures 1 [2 to 4, which show the configuration], Figure 5 shows the configuration.
The operation explanatory diagrams in FIGS. 9 to 9 and the timing chart shown in FIG. 10 are incorporated herein by reference.

A sheet is placed on the sheet stacker 22. At this time, the solenoid 38 is not yet energized, and the gate stopper 37 is flipped upward and holds the front edge of the sheet. Further, the solenoid 36 is also in an OFF state, and the weight 35 is located away from the seat.

Then press the paper feed start button (not shown) and press the copying machine 1.
When the engine is started, the solenoid 36 is turned on after a minute interval, and the weight 35 comes into contact with the sheet and presses it downward, as shown in the timing chart of FIG. Then, after a while, the rear kick roller 32 and the cutting roller 41 start rotating at the same time. However, the solenoid 38 turns ON only after a very small moment.
A gate stopper 37 prevents the sheet from advancing in order to align the paper edge with the time element. In addition, in the above action,
When the sheet stacker 22 is not replenished with sheets, an alarm is issued by detection by the empty sensor 65, and the apparatus 1 does not start.

Then, the flJli sheet is transferred to the kick roller 32.
As shown in FIG. 5, it moves forward as a whole and comes into contact with a rigid handling plate 42 having an acute angle of attack a, and is brought to an M position.

Then, the lower plural sheets pass through the first passage gap a. Furthermore, these sheets are attached to the second sheet as shown in Figure 6.
The smallest sheet passes through a second passing gap which is smaller than the first passing gap a.

The sheet then enters the separating means 40, and since the angle of attack β at the leading edge of the pad 46 is smaller than the angle of attack a of the rigid separating plate 42, a separating action is also performed here. Ru. The sheet then enters a separating means 40 composed of a separating roller 41 and a pad body 45.

The sheet that has entered the separation means 40 acts to push open the pad body 45, but as it is pushed open, the contact point P, which is the pressure contact point between the pad body 45 and the body roller 41, moves to the paper feeding downstream side. Furthermore, since the part supported by the support plate 48 of the pad body 45, that is, the engagement part 51 of the pad holder 47, is provided at a downstream side in the paper feeding direction and at a separate position, the contact point P is separated from the engagement part 51. Arm length of swing up to S
decreases, and the biasing force of the biasing spring 50 increases relatively, so that even if a plurality of sheets enter the separating means 40, the separating action is reliably performed.

Since the coefficient of friction of the pad 46 is larger than that of the mutual sheets and smaller than that of the surface of the separating roller 41, if two sheets have entered so far, the upper sheet will be The sheet remains on the side, and the sheet on the side of the sorting roller 41 continues to be fed.

Further, when only one sheet is fed, the lower surface of the sheet receives a stronger drag force, so that the sheet is fed out as it is. Since the angle of attack γ between the lower surface of the pad 46 and the sheet before the pad 46 comes into contact with the bending roller 41 is made smaller, the separation effect is further ensured. The sheet handling effect accompanying the decrease in the angle of attack is shown more clearly with reference to FIG.

The sheet separated into one sheet by the separating means 40 advances along the curved lower surface of the pad 46, and the front end of the sheet is once lowered into the registration space 6o formed by the sheet guide plate 31 that is largely bent downward. Then, the sheet rises again along the sheet guide plate 31 and is nipped by the registration rollers 61 and 62.

Immediately before that, the registration sensor 66 issues a paper edge detection signal. This detection signal causes the minute rear kick roller 32 and the separation roller 41 to stop. After a few more hours, the registration rollers 61 and 62 begin to rotate.6 Normally, at this point, the trailing edge of the sheet is still in the separation means 4.
0, and gradually becomes tense as the registration rollers 61 and 62 rotate.

However, as shown in FIGS. 2, 8, 9, etc., the nip point R of the registration rollers 61, 62 is biased upward from the direction A in which the curved tangent of the body roller 41 of the separating means 40 extends. In addition, the tip of the pad 46 is provided with a protrusion 46a that protrudes downward, so that as the sheet becomes tense, the tip of the pad body 45 moves upward with the contact point P as a fulcrum. The contact point P also moves to the upstream side of paper feeding, and the angle of attack T also becomes smaller. This swinging of the pad body 45 requires a pad holder 4 as shown in FIG.
The backlash 51a of the engaging portion 51 provided at the rear edge of 7 contributes effectively.

By moving the contact point P upstream, the registration roller 6
While the force for capturing the leading edge of one sheet, which has reached 1.62, is relaxed, the decrease in the angle of attack γ makes it more difficult to prevent the subsequent sheets from entering.

The sheet fed by the registration rollers 61 and 62 is delivered to the conveying section 24 via the sheet guide 63, positioned on the platen 3 of the copying apparatus 1, and subjected to copying processing.
The sheet is again discharged to the sheet discharge stacker 23 by the action of the conveying section 24.

[Effects of the Invention] The present invention includes a paper feeding rotary body that rotates in the sheet feeding direction;
A paper feeding device comprising a separating means comprising a pad body that presses against the paper feed rotary body to prevent double feeding of sheets, and a biasing means that presses the paper feed rotary body, wherein the pad body is It is held at three points: a press-contact part with the paper feed rotor, a biasing force part of the urging means, and a support part by the device frame, and the support part by the device frame is held by the pad body and the paper feed rotor. Since the pad body is swingably supported at the tip thereof which is located a distance downstream in the paper feeding direction from the pressure contact area with the pad body, it is easy to change the relative positions of several supporting parts that hold the pad body. With technology,
This not only improves sheet separation performance and prevents double feeds and non-feeds, but also reduces the driving power of the paper feed rotor.

[Brief explanation of the drawing]

FIGS. 1 to 10 show an embodiment of this invention,
Figure 1 is a vertical cross-sectional view of the paper feeding section, Figure 2 is an enlarged configuration diagram showing the main parts near the separation means, Figure 3 is a configuration diagram showing the entire paper feeding device, and Figure 4 is an electronic The overall drawing of the copying device, FIGS. 5 and 6 are illustrations of the effects of each sorting means, FIG. 7 is an illustration of the effects of the angle of attack, and FIGS. 8 and 9 are illustrations of the effects of the sheets nipped by the registration rollers. Explanatory diagram, 1st
FIG. 0 is a timing chart, and FIGS. 11 and 12 are explanatory diagrams of main parts of a conventional paper feeding device. 1 Secondary copying device 2 Main body 3 Platen 4 Paper cassette 5 Paper ejection tray 6 Exposure lamp 7 Mirror group 8 Variable magnification lens block 9 Photosensitive drum 10 Developing device 11 Transfer device! ffi 12 Fixing device 2
0 Paper feeding device 21 Main body frame (apparatus frame) 22 Sheet stacker 23 Paper discharge stacker 24 v&
Feeding section 30 Paper feeding section 31 Sheet guide plate 32 Kick roller feeding means) 35 Weight 36 Solenoid 37 Gate stopper 38 Solenoid 40 Separation means 41 Sorting roller (sheet feeding rotating body) 42 W4 sorting plate a First passage gap 43 Elastic side plate b Second passing gap 2-point pad body 46 Pad Pad holder support plate Contact point (pressure contact point) between the sorting roller and the pad Protrusion biasing spring (biasing means) Retaining unit (supported by the device frame) Part) a Backlash of the engaging part Distance wl between point P and the engaging part (swing arm length) Angle of attack resist space 62 of the flat part of the angle of attack pad at the tip of the angle of attack pad of the rigid handling plate Registration roller empty sensor resist Force point of sensor biasing spring (biasing force location) Registration roller chive 1 point 6a S/β 61, Q point R point Fig. 5 Fig. 6

Claims (1)

[Claims] A stacker for stacking and accommodating sheets, a feeding means for feeding the sheet against the uppermost or lowest sheet of the sheets stored in the stacker, and a feeding means provided downstream of the feeding means in the sheet feeding direction. A paper feeder comprising: a paper feed rotor that rotates in the feeding direction; a pad body that comes into pressure contact with the paper feed rotor to prevent double feeding of sheets; and a separating means that includes a biasing means that presses the paper feed rotor. In the device,
The pad body is held at three points: a pressure contact area with the paper feeding rotary body, an urging force area of the urging means, and a support area by the apparatus frame, and the support area by the apparatus frame is A paper feeding device characterized in that the pad body is swingably supported at a rear end portion of the pad body which is spaced downstream in the paper feeding direction from the pressure contact portion between the pad body and the paper feeding rotating body.