JPH02178133A - Paper feeder - Google Patents

Abstract

PURPOSE:To prevent any double feed and a paper jam from occurring by installing a first handling means, opposedly contacting with a sheet front edge and arranging it in order, and a second handling means approximating to the downstream side of a sheet route both in this sheet route leading to a separating means from a stacker, respectively. CONSTITUTION:Each sheet mounted on a stacker is arranged of its front edge in order by a rigid handling plate first handling means) 42, whose attack angle is an accute angle, by action of a kick roller 32, and plural numbers of sheets in succession to a lowermost sheet pass through a clearance between this rigid handling plate 42 and a sheet guide plate 31. An elastic handling plate (second handling means) 43 installed at the downstream side of a sheet route of this rigid handling plate 42 is fed to a separating means 40 after making the number of sheets into minimum numbers because a passing clearance with the sheet guide plate 31 is narrower than the first one, and that it is constituted of an elastic material. Thus, sheet jamming and double feeding are preventable irrespective of thickness and stiffness of the sheet.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is applicable 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. Pause.

[Prior Art] A stacker for stacking and accommodating sheets, a feeding means for feeding out sheets against the uppermost or lowest sheet of the sheets stored in the stacker, and a feeding means provided close to the tip of the stacker to A feeder 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 machine, etc. Conventionally, in a paper machine, a separating means is provided near the delivery end of the stacker, and the opening means is made of a rigid material, and the separating means is arranged in contact with the leading edge of the sheet. A gap was provided for the sheet to pass through.

[Problems to be Solved by the Invention] However, in such conventional paper feeding devices, when the sheet passing gap is made smaller in order to improve sheet separation performance, sheet jamming may occur depending on the thickness of the sheet. On the other hand, if the sheet passing gap is increased in order to avoid such sheet jams, the number of sheets passing through becomes too large, causing so-called double feed.

In order to eliminate the above-mentioned problems, it is considered to minimize the passage gap of the sheet and to construct the sorting means by using an elastic body as the side means or biasing a rigid body with a spring or the like. However, depending on the relationship between the strength of the elastic force and the stiffness of the sheet, for example, if the sheet is stiff, a large number of sheets may pass through against the elastic force of the sorting means, and on the other hand, it may be difficult to resist the elastic force. There is a problem that a sheet with weak leverage cannot be passed through, resulting in non-feed.

Furthermore, in order to prevent sheet jams from occurring when dealing with thick and stiff sheets, a large amount of power is required in the feeding means. There is also the problem that it further encourages sheet feeding.

[Object of the Invention] The present invention has been made in view of the problems in the conventional technology, and it is possible to prevent sheet jams and multi-sheet feeding, regardless of the thickness of the sheet or the strength of the strainer. It is an object of the present invention to provide a paper feeding device in which the feeding power of the feeding means is small.

[Means for Solving the Problems] The gist of the present invention for achieving the above object is to provide a stacker for stacking and accommodating sheets.

A feeding means for feeding out a sheet against the uppermost or lowest sheet of the sheets stored in the stacker, and a feeding means provided on the downstream side of the feeding means in the sheet feeding direction to feed the sheets one by one from the feeding means. In the sheet feeding apparatus, a first sheet feeder is provided with a sheet path leading from the stacker to the separating means, and a first sheet is provided in the sheet path from the stacker to the separating means, and is arranged opposite to the leading edge of the sheets to organize the sheets.
and a second handling means adjacent to the downstream side of the sheet path of the first handling means, the first handling means being a rigid plate that does not deform by the sheet feeding force, The angle of attack relative to the feeding direction of the sheet is formed at an acute angle with respect to the feeding direction of the sheet, and a first passage gap is provided in the sheet path at the leading end thereof. In addition, the second handling means is formed of an elastic plate that can be deformed by the force of feeding out the sheet, faces at an acute angle with respect to the sheet, and has a tip of the elastic plate and the sheet path from the first passing gap. The present invention resides in a paper feeding device characterized by providing a narrow second passage gap.

[Operation] Due to the action of the feeding means, the sheets inserted into the stacker are sorted by the first sorting means having an acute angle of attack, and the lowest or highest sheet and the lowest or highest sheet are stacked. Multiple sheets following the upper sheet are
The sheet is fed downstream through a first passage gap provided between the first handling means and the sheet path.

Since the first sorting means is made of a rigid material that does not deform due to the sheet feeding force, thick and stiff sheets are divided into the minimum number of sheets here and sent to the next stage of the second sorting means. .

A slightly larger number of thin sheets are sent to the next stage by the first sorting means.

A second passage gap of the sheet provided between the second separating means and the path of the first opening means
Since the passage gap is narrower than the passing gap and is made of an elastic material, a slightly larger number of thin sheets that have passed through the first separating means will become the minimum number at that point and be separated. Sent to means.

Implementation g74] 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, a paper feed cassette 4 for supplying copy sheets on one side, and a paper feed cassette 4 on the other side. There is a paper output tray 5 for receiving copied copy sheets.
is installed.

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

Paper feed section! 20 is the main body frame 21 as shown in FIG.
a sheet stun force 22 for placing the original sheet on top;
A paper feed section 30 feeds sheets one by one, and original sheets are conveyed onto the platen 3 of the main body 2 of the apparatus and placed there, and after the copying process is completed, are further discharged to the rear and discharged to the paper discharge stacker 23. It consists of a transport section 24 (J).

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. When the solenoid 38 is energized, it rotates counterclockwise in FIG. 1 and is pulled down to the lower surface of the sheet guide plate 31.

A separating roller 41 constituting a separating means 40 is disposed alongside the kick roller 32, and a portion of its outer cylindrical surface is exposed on the upper surface of the sheet guide plate 31 as shown.

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, on the back surface of the rigid separating plate 42, an elastic separating plate 43 is attached as a second separating means, which is made of an elastic material such as a flexible elastic film or a thin metal piece, which is deformed by the force of feeding out the sheet. A second sheet passage gap is provided between the lower edge of the sheet and the separating roller 41.

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 double-sided plate 42, 43 with the upper surface of the seat is approximately 50' to 57', but of course it is not limited to this value. .

Next, a bad block 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 block 45 consists of a pad 46 that comes into contact with the separating roller 41 and separates the sheets one by one, and a pad holder 47 that holds this pad 46.

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

As shown in the figure, from the contact point P on the lower surface of the pad 46 to the paper feeding direction, the pad 46 has an arc shape having a radius of curvature 6 larger than the radius of curvature of the separating roller 41,
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, and therefore the angle of attack is also an angle r. The pad 46 is made of a rubber-like soft material.
For example, urethane rubber with a hardness of 80 degrees is used, and is harder and has a rougher bottom drag coefficient than the separating roller 41, but has a larger friction coefficient than the friction coefficient between the sheets.

On the other hand, the pad holder 47 holding the pad 46 is
As shown in the figure, the engagement portion 51 at the tip is connected to the main body frame 21.
A biasing spring 50, which is a biasing means, is supported by a support plate 48 of
It is pressed in the direction of the separating roller 41 by.

That is, the pad block 45 as a whole is supported by three points: the point P, the force application point Q of the biasing spring 5o, and the engaging portion 51.

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 one or more backlashes 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 away 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 sheet.

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, T is a>β>γ The relationship between

On the downstream side of the separation means 40, there are registration rollers 61 and 62, which are composed of a pair of rollers that deliver the sheet to the conveying section 24, separated by a registration space 6° formed by bending the sheet guide plate 31. It is provided. Then, the sheet is transferred to the conveying section 24 on the exit side of the registration rollers 61 and 62.
A sheet guide 63 is provided to guide the sheet.

As shown in FIGS. 8 and 9, the contact point of both registration rollers 61 and 62, that is, the nip point R at which the sheet is gripped, is the pad 46 whose radius of curvature is larger than the radius of curvature of the separating roller 41. It is located above the tangential direction A at the curved tip.

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 explaining one action, in addition to FIGS. 1 to 4 showing the configuration, the action explanatory diagrams in FIGS. 5 to 9 and the timing chart shown in FIG. 10 will be used.

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 turned off, 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 turns on after a minute interval, as shown in the timing chart of Fig. 10.
The weight 35 then comes into contact with the sheet and presses it downward. After a while, the rear kick roller 32 and the separating roller 41 start rotating at the same time. However, the solenoid 38 is only turned on after a very small time interval, and the gate stopper 37 prevents the sheet from advancing in order to align the paper edge between the time intervals. Note that in the above operation, 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.

The stacked sheets then move forward as a whole as the kick roller 32 rotates, and as shown in FIG. 5, come into contact with a rigid sorting plate 42 having an acute angle of attack a, and are tidyed up. Then, the lower plural sheets pass through the first passage gap a.

Furthermore, as shown in FIG. 6, these sheets are pressed against an elastic separating plate 43, which is a second separating means, and are passed through a second passage gap smaller than the first passage gap a, into a minimum number of sheets. The sheets are passing by.

Therefore, for stiff and thick sheets, use the rigid handling plate 4.
Most of the sheets are dammed up at 2, and sheets exceeding 217ρ1 to 3 are further separated by an elastic spread plate 43. Incidentally, when the sheet is thick, the elastic separating plate 43 is pushed up by the sheet, so there is a risk of the sheet becoming jammed, and the elastic separating plate 43 reliably acts on both thick and thin sheets.

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 α of the rigid separating plate 42, a separating action is also performed here. Ru. The sheet then enters a separation means 40 comprising an opening roller 41 and a bad block 45.

Since the coefficient of friction of the pad 46 is thicker than that of the mutual sheets and smaller than that of the surface of the cutting roller 41, if two sheets have entered so far, the upper sheet will be The sheet stops at the bar 46 (Ill), and the sheet on the sorting roller 41 side continues to be fed.

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. The band 46 handles the roller 41
Since the attack angle T between the lower surface of the pad 46 and the sheet before contacting the pad 46 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 leading edge of the sheet is once lowered into the registration space 60 formed by the sheet guide plate 31 that is largely bent downward. Then, it rises again along the sheet guide plate 31 and is pushed up again 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. Normally, at this point, the trailing edge of the sheet is still at the separating 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 and '62 is biased upward from the direction A in which the curved tangent of the separating roller 41 of the separating means 40 extends. Not only that, but the tip of the pad 46 is provided with a protrusion 46a that protrudes downward, so that as the sheet is tensed, the tip of the pad block 45 is lifted upward using the contact point P as a fulcrum. As a result, the contact point P also moves to the upstream side of paper feeding, and the angle of attack γ also becomes smaller.

This swinging of the pad block 45 requires the engaging portion 51 provided at the tip of the pad holder 47 as shown in FIG.
The backlash 51a contributes effectively.

By moving the contact point P upstream, the registration roller 6
While the force for capturing the trailing 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 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 provides first and second handling means having first and second passage gaps on the sheet path, and the first handling means is not deformed by the sheet feeding force; The second handling means is deformable by the opening force, and both of the handling means face the sheet at an acute angle, and the second passage gap is configured to be smaller than the first passage gap,
Regardless of the thickness of the sheet or the strength of the strainer, it is possible to avoid sheet jams or feed multiple sheets, and to reduce the feeding power of the feeding means.

[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
Figure 0 is a timing chart. 1 Electronic copying device 2 Main body 3 Platen 4 Paper cassette 5 Paper ejection tray 6 Exposure lamp 7 Mirror group 8 Lens block for variable magnification Photosensitive drum Developing device Transfer device Fixing device Paper feeding device Main body frame Sheet stacker Paper stacker transport section feeding Paper part seat guide plate kick roller (Ii output means) Weight solenoid gate stopper Solenoid separation means Sorting roller Rigid separating plate (first sorting means) First passage gap 43 Elastic separating plate (second sorting means) b Second Passing gap 45 Bad block 46 Bad 47 Bad holder P point Contact point 46a between the sorting roller and the bad Protruding part 50 Biasing spring 51 Engaging part 51a Distance between backlash sP point of the engaging part and the engaging part Aliil handling plate Angle of attack β Angle of attack T at the tip of the pad Angle of attack at the flat part of the pad 60 Registration space 61.62 Registration roller 65 Empty sensor 66 Registration sensor point Q Forced point of biasing spring R point Point 2 of the registration roller

Claims (1)

[Scope of 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 downstream side of the feeding means in the sheet feeding direction. and separating means for separating the sheets from the feeding means one by one, the sheet feeder comprising: a separating means for separating the sheets from the feeding means one by one; a first sorting means and a second sorting means adjacent to the downstream side of the sheet path of the first sorting means, the first sorting means being a rigid plate that does not deform by the sheet feeding force; The angle of attack with respect to the sheet is formed at an acute angle with respect to the feeding direction of the sheet, and a first passing gap is provided between the leading end of the sheet and the sheet path; A second passage gap, which is configured as a deformable elastic plate, faces the sheet at an acute angle, and is narrower than the first passage gap, is provided between the tip of the elastic plate and the sheet path. A paper feeding device featuring: