JPH11139577A - Paper sheet feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a paper sheet feeding device capable of preveting the occurrence of a jam even if a sheet is set at a position drifted backward in the feeding direction from the specified position. SOLUTION: A middle plate 13 is rotatably provided on a sheet storage means, the middle plate 13 is excited by an exciting member toward a feeding means 11 to bring the feed side end section of a sheet 37 loaded on the middle plate 13 into pressure contact with the feeding means 11, and the feed side end section of the sheet 37 is corrugated in the direction perpendicular to the feeding direction of the sheet 37 by the irregularities formed at the rotating end section of the middle plate 13. Since the feed side end section is corrugated, the rigidity of the sheet 37 is increased. Even if the feed side end section 40 of a next fed sheet 38 pulled by the fed sheet 37 is pressed by the rear end section of the fed sheet 37 when the fed sheet 37 is fed in the direction different from the feeding direction before separation, the deformation of the feed side end section 40 can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device used in an image forming apparatus such as a printer or a copying machine, and more particularly, to feed a sheet separated by a separating means in a direction different from a feeding direction before separation. Regarding the configuration.

[0002]

2. Description of the Related Art Conventionally, there is a paper feeder which feeds sheets stored in a sheet storage means by a feeding means and separates and feeds the sheets one by one by a separation means.
In such a sheet feeding device, before the cassette is mounted on a printer, a copying machine, or the like, the sheets are stacked on the middle plate of the cassette, and positioned according to the sheet size by the side regulating member and the rear end regulating member, Thereafter, a cassette was mounted so that the top sheet could be picked up.

The middle plate of the cassette is configured to rotate in an arc shape around a support member provided in the middle of the cassette, and is mounted on the middle plate by the rotation of the middle plate. The leading end of the sheet thus drawn also draws a similar trajectory. When the number of stacked sheets decreases, the rotation angle of the middle plate increases, and as the rotation angle increases, the contact area between the leading end portion of the sheet and the sheet feeding roller decreases, and sheet feeding is not performed. Will not work properly.

On the other hand, the cassette is provided with a side regulating plate and a rear end regulating plate for setting the sheet at an appropriate position. The set positions of the side regulating plate and the rear end regulating plate are determined by the size of the sheet. The sheet is set to be wider by 1 to 2 mm than the sheet size in consideration of the variation of the sheet and the elongation due to moisture absorption.

Here, in a cassette (hereinafter, referred to as a universal cassette) in which the side regulating plate and the rear end regulating plate can be freely changed according to the size of the sheet, it is surprisingly difficult to set paper in accordance with the sheet size.
Depending on the user, the side regulating plate or the rear end regulating plate may be set so that a gap of 4 to 5 mm is left between the sheet and the sheet. However, when the sheets are set in this way, when the size of the sheets is small and the number of stacked sheets is small, paper feeding failure is particularly likely to occur.

In order to solve such a problem, a leaf spring is provided on a trailing end regulating plate to press the trailing end of a sheet, for example, as in a paper feeder disclosed in Japanese Patent Application Laid-Open No. 7-137848. Also, there has been proposed a paper feeder disclosed in Japanese Patent Application Laid-Open No. 7-101564 in which the middle plate is moved up and down in a horizontal state.

In the sheet feeding device, in order to save space, the sheet feeding direction of the picked-up sheet is set at 18 degrees.
There is an apparatus in which a U-shaped guide is provided to guide the sheet into the main body by turning the sheet by 0 degrees.

[0008]

However, in the conventional sheet feeding device in which the rear end of the sheet is pressed by the rear end regulating plate, if the sheet is frictionally charged and strongly adheres to the middle plate, May not move forward, in which case,
There has been a problem that the rear end of the sheet is bent or curled.

Further, the conventional paper feeding device in which the middle plate is moved up and down in a horizontal state not only requires a complicated mechanism but also requires a lot of space, and is not suitable for a small paper feeding device. There was a point.

On the other hand, in a conventional sheet feeding apparatus in which the traveling direction of the sheet is reversed by 180 degrees, the traveling direction of the sheet picked up by the feed roller and the sheet determined by the feed roller and the separating means are determined. Since the direction of travel is greatly different, the following problem occurs.

That is, when the trailing end of the first sheet fed to the separation means after being picked up by the feeding roller comes out of the cassette, the second sheet is pulled out from the cassette. This is because the paper feed roller is switched from the driving state to the driven state after the pickup and is not actively feeding the paper, but cannot be stopped suddenly and rotates a little by inertia.

Here, the cassette and the separating means are designed to be close to each other. However, a gap of about 2 mm is generated due to tolerances of parts and the like. When the direction of the first sheet changes, the trailing edge of the first sheet strongly presses the leading edge of the second sheet downward, so that the leading edge of the second sheet becomes a cassette. It comes into the gap with the friction separating means.

If the sheet feed roller tries to pick up this sheet in this state, the leading end of the sheet is bent and fed, and stops inside the main body (a so-called jam state). Here, if the sheet is set in the normal state, there is not much problem.However, if the rear end regulating plate is set with a large shift rearward, the sheet is shifted rearward in the feeding direction from the specified position. And the gap is further increased, so that the second and subsequent sheets are easily jammed.

Conventionally, cassettes are often inserted and removed from the side (right or left side). However, due to improvement in operability and user demand, cassettes which are inserted and removed from the front of the apparatus have recently been called front loading. In such a cassette, a gap is easily formed between the cassette and the main body, and the above-described problem is particularly likely to occur.

Therefore, the present invention has been made to solve the above problems, and prevents the occurrence of a jam even when a sheet is set to be shifted rearward in a feeding direction from a predetermined position. It is an object of the present invention to provide a paper feeding device capable of performing the above-described operations.

It is another object of the present invention to provide a sheet feeding device capable of indicating a shift when a sheet is set rearward in a feeding direction.

[0017]

According to the present invention, sheets stored and stored in sheet storage means are fed by feeding means, and the fed sheets are taken out with the fed sheets. In a sheet feeding device that separates a next sheet to be fed by a separating unit and then feeds the sheet in a direction different from a feeding direction before the separation, the sheet is rotatably provided in the sheet storage unit, and the sheet is stacked. A plate, an urging member for urging the middle plate toward the feeding means so as to press the feeding side end of the sheet stacked on the middle plate against the feeding means, and a rotating end of the middle plate. And a concave / convex portion for waving a feeding side end of the sheet pressed against the feeding means in a direction orthogonal to the feeding direction of the sheet. The feeding side end is made to wave, and the fed sheet is Obtaining time, is characterized in that it has to suppress the deformation of the feeding end of said next time feeding sheet which is pressed by the rear end of the sheet.

In the present invention, the uneven portion may include a flat portion formed at a rotating end of the intermediate plate, and convex portions formed on both sides of the flat portion in a direction orthogonal to a sheet feeding direction. Alternatively, it is characterized by comprising a concave portion and a concave portion or a convex portion formed on both sides of the convex portion or the concave portion in a direction perpendicular to the sheet feeding direction.

In the present invention, a restricting member which restricts the movement of the stacked sheets by contacting the side end opposite to the feeding side of the stacked sheets can be moved in the feeding direction. On the other hand, when the sheets are stacked in a direction away from the rotating end of the middle plate due to the position of the regulating member, a mark indicating that the sheets are stacked with a gap is provided. It is characterized by being provided at the moving end.

Further, in the present invention, the mark is provided on a first mark indicating a sheet feedable area provided substantially in parallel with a rotating end of the intermediate plate, and on a regulating member side of the first mark. And a second mark indicating a non-feedable area.

Further, the present invention is characterized in that the first mark and the second mark are displayed in different colors.

Further, the present invention is characterized in that the diameter of the feeding means has a predetermined size such that the direction before the separation and the direction after the separation are largely different.

Further, as in the present invention, an intermediate plate for loading sheets in the sheet storage means is rotatably provided, and the intermediate plate is urged toward the feeding means by an urging member to be loaded on the intermediate plate. The sheet feeding side end of the sheet is pressed against the feeding means, so that the sheet feeding side end is oriented in a direction orthogonal to the sheet feeding direction by the uneven portion formed at the rotating end of the middle plate. Make it undulate. By waving the feeding side end in this way to increase the rigidity of the sheet, when the fed sheet is fed in a direction different from the feeding direction before separation, the sheet is fed. Even if the feeding side end of the next fed sheet taken out along with the fed sheet is pressed by the rear end of the fed sheet, deformation of the feeding side end of the next fed sheet is suppressed. Can be.

[0024]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view of a copying machine which is an example of an image forming apparatus provided with a sheet feeding device according to the first embodiment of the present invention. In the figure, 1A is a copying machine main body (hereinafter, referred to as a main body).
The main body 1 includes an image reading unit 1 for reading an image of a document, and an image forming unit 2 for forming an image based on information read from the image reading unit 1. I have.

Reference numeral 3 denotes a mirror base of the image reading unit 1. The mirror 3 scans an original (not shown) and reflects reflected light of the light source 3a to mirrors 3b, 4a, 4b, a zoom lens 5, a mirror 6, and so on. An original image is radiated onto the surface of the photosensitive drum 9 of the image forming unit 2 via 7 and 8.

On the other hand, reference numeral 10 denotes a process cartridge of the image forming section 2, and this process cartridge 10 develops a latent image on the photosensitive drum 9 and feeds a sheet cassette 29 described later.
The toner image is transferred onto a sheet fed and conveyed from the printer. The sheet 31 to which the toner image has been transferred is
The toner image is sent to the fixing device by the transport belt 22 to thermally fix the toner image, and then discharged onto the paper discharge tray 27.

In FIG. 1, reference numerals 1a and 2a denote the main body 1.
The first frame 1a and the second frame 2a are connected by a hinge 28, and if a release hook 28a provided on the opposite side is removed,
The first frame 1a opens in an alligator shape at an opening angle of about 45 degrees.

On the other hand, in the figure, reference numeral 29 denotes a sheet cassette which is a so-called front loading type sheet storage means which is attached to the lower part of the main body 1 so as to be able to be pulled out to the front side. It can be pulled out by a handle (not shown). Also,
The sheets stored in the sheet cassette 29 are picked up by a feeding roller 11 serving as a feeding unit, separated by a separation pad 12 serving as a separating device, and passed through a U-turn guide 18 to a registration roller pair 19. Sent.
Thereafter, the sheet once stopped by the registration roller pair 19 is conveyed at a constant speed in synchronization with the toner image on the photosensitive drum 9.

By the way, as shown in FIG. 2, the paper feed cassette 29 has side regulating plates 34a and 34b for regulating the width of the sheets so that sheets of various sizes can be fed.
A rear end regulating plate 15, which is a regulating member that regulates the movement of the sheet by contacting a rear end which is a side end opposite to the leading end (feed side end) of the sheet, and an intermediate plate 13.

Here, the side regulating plates 34a, 34b are racks 34c, which mesh with the pinion gear 35 shown by broken lines.
34d, and moves symmetrically around the pinion gear 35, and is set by a lock member (not shown) in accordance with the paper width of A4 size, A5 size, or the like.

The rear end regulating plate 15 is formed substantially at the center of the cassette 29 and at a position deviated from the middle plate 13, and is provided movably along a groove 36 extending in the feeding direction. And claws 37a provided on both sides of the groove 36,
By locking the engaging claw 15c provided on the lower side of the handle 15b shown in FIG. 1 with the 37b, locking can be performed at an arbitrary position.

On the other hand, the middle plate 13 is provided with pins 33a, 33a provided in the middle of two side walls 33A, 33B of the sheet cassette 29 shown in FIG.
The holes 13a, 13b are fitted into the holes 13a, 13b provided on both end surfaces of the intermediate plate 13 as shown in FIG.
With reference to 13b as a fulcrum, it is rotated between an inclined position (a state where the load is small) and a substantially horizontal position (a state where the load is large) shown in FIG.

Further, the middle plate 13 is constantly pressurized by a spring 14 as an urging member so as to be rotatable upward, so that the sheet stacked on the middle plate 13 is fed at the feeding end. A certain leading end portion comes into pressure contact with the feed roller 11.

Meanwhile, a recess 13e is provided in a region facing the feeding roller 11 at the feeding end, which is the rotating end of the intermediate plate 13, as shown in FIGS. 3 and 4A. The recess 13e is provided with a cork pad (high friction member) 17 for preventing double feeding of sheets. Here, the depth of the concave portion 13e is an amount corresponding to the thickness of the cork pad 17, and the bottom surface of the concave portion 13e is inclined downward to the right so as to incline slightly below the middle plate main body 13A.

On the other hand, 13j shown by a broken line in FIG. 3 is a first inclined portion provided on the side (rear side) of the concave portion 13e along the feeding end as shown in FIG. As shown in FIG. 4B, the portion 13j is provided with the middle plate body 13A (and the concave portion 1).
3e) It is inclined upward, that is, upward to the right. In addition,
As shown in FIG. 2, the second inclined portion 13g provided on the side (front side) opposite to the first inclined portion forming side of the concave portion 13e is also inclined at the same angle as the first inclined portion 13j.

Further, as shown in FIG.
A third inclined portion 13k is provided on the back side of j, and the third inclined portion 13k is slightly below the angle of the middle plate main body 13A, that is, lowering to the right as shown in FIG. It is inclined. Further, the fourth inclined portion 13f on the front side of the second inclined portion 13g shown in FIG. 2 is also inclined at the same angle as the third inclined portion 13k. FIG. 4D shows 13h and 13i.
Are concave portions 13e and first and second inclined portions 13g and 13j.
And a flat portion provided between the two.

Then, as described above, at the feeding end of the intermediate plate 13,
As shown in FIG. 2, the concave portion 13 whose bottom surface is inclined slightly downward.
e, first and second inclined portions 13 inclined upward to the right
g, 13j, and the concave and convex portion 13B composed of the third and fourth inclined portions 13f, 13k inclined downward to the right, so that when the intermediate plate 13 is pressed against the feeding roller 11, At the leading end of the placed sheet, undulations occur in a direction orthogonal to the large feeding direction, thereby increasing the stiffness of the sheet at the leading end, that is, increasing the rigidity.

In FIG. 3, reference numeral 37 denotes a sheet (hereinafter, referred to as a first sheet) conveyed by the feed roller 11 and the separation pad 12, and reference numeral 38 denotes a sheet which is taken out of the first sheet 37. The next feed sheet 2
This is the first sheet. FIG. 5 shows that the leading end 40 of the second sheet 38 is several mm from the normal position 38a.
The state where the user has entered the entrance of the separation pad 12 from the lowered position 38b is shown.

When the first sheet 37 is being conveyed by the feeding roller 11 and the separation pad 12, the sheet 37 receives a conveying force at the contact portion between the separation pad 12 and the feeding roller 11. This transport direction is the direction of arrow P, which is different from the exit direction indicated by arrow R when sheet 37 exits from cassette 29.

When the sheet feeding direction, which is the direction before separation, and the exit direction, which is the direction after separation, are different from each other, when the sheet 37 exits from the cassette 29, the sheet 37 follows the cassette 29 and the feed roller 11 until that time. Sheet 3
The rear end of the shutter 7 is momentarily opened to rotate counterclockwise, that is, downward.

Here, when the rear end of the sheet 37 rotates downward in this manner, the leading end 40 of the second sheet 38 that has been protruded by the first sheet 37 is attached to the sheet 3.
The rear end portion 7 can be bent downward.
At this time, when the rigidity of the sheet 38 is low, the leading end 40 of the second sheet 38 is greatly bent as shown by the broken line, enters the gap S between the separation pad 12 and the middle plate 13 and stops. Become like

However, the rigidity can be increased by generating a large waving at the front end portion 40 of the sheet 38 as in the present invention, whereby the first sheet 37 can be bent downward by the rear end portion. Even if the tip 40
The bending amount (deformation) of the separation pad 12 is suppressed, and it enters the entrance of the separation pad 12. The second sheet 38 that has thus entered the entrance of the separation pad 12
Is separated from the first sheet 37 by the separation pad 12, and is conveyed into the main body by the feeding roller 11 and the separation pad 12 after the conveyance of the first sheet 37.

Here, as a comparison of the rigidity of the tip portion 40,
For example, when the sheet is protruded by 50 mm from the middle plate 13, the leading end portion (though it is impossible to feed the sheet in a state where the sheet is protruded by 50 mm in the cassette), the conventional middle plate (simply flat) hangs down by 5 mm. On the other hand, in the case of the middle plate 13 of the present invention, even if the middle plate 13 is protruded by 50 mm, it is lowered only by 0 to 1 mm.

On the other hand, the following table shows various types of sheets.
When 0, 150 or 250 sheets are stacked, the rear end regulating plate 1
This indicates the paper feeding performance of how much paper 5 can be fed even if it is shifted backward. Here, the data in the table are based on environmental conditions at normal temperature (22.5 degrees) and low humidity (5%). In addition, high temperature and humidity (30 degrees, 80
%), 23 degrees, and 60%, the same result is obtained.

[0046]

[Table 1] As is clear from this table, if the middle plate 13 of the present invention is used, it is possible to feed the paper even if the rear end regulating plate 15 is shifted backward by 3.5 mm to 4.5 mm. On the other hand, in the case of using the conventional middle plate, the rear end regulating plate is 1.5 m
When it was shifted backward by m to 2 mm, a jam or the like occurred.

From this, it can be understood that the use of the middle plate 13 of the present invention allows normal feeding even if the rear end regulating plate 15 is shifted at least by about 3 to 3.5 mm behind.
As described above, by increasing the rigidity of the sheet by waving the front end portion 40 of the sheet, it is possible to prevent the occurrence of a sheet jam even when the sheet is set slightly behind.

In recent years, the use efficiency of space in offices and the like has been increasing more and more, so that the diameter of the paper feed roller 11 tends to be smaller due to the configuration. Therefore, the margin of the rear end regulating plate 15 with respect to the displacement amount is reduced, and the effect of the middle plate 13 of the present invention is further enhanced.

In this embodiment, the feed roller 11 has a diameter of 36 mm. However, the feed roller 11 is not necessarily limited to the diameter of 36 mm. What is necessary is just a predetermined dimension. For example, when the diameter of the paper feed roller 11 is 40 mm or less, the direction in which the fed sheet advances and the tangential direction separated by the separation pad greatly differ from each other by 20 to 30 degrees.

Next, a second embodiment of the present invention will be described.

FIG. 6 is a plan view of the cassette of the sheet feeder according to the present embodiment in which sheets are stacked. The same reference numerals as those in FIG. 2 indicate the same members.

In the figure, reference numeral 50 denotes a middle plate. When a sheet is shifted rearward at the feeding end of the middle plate 50 depending on the setting position of the rear end regulating plate 15, the sheet is shifted and stacked. The three areas, which are marks for indicating that the operation is performed, are shown in different colors.

In this embodiment, an area 51 closest to the feeding end (hereinafter referred to as a first area) 51 has a width of 2.
Green hatching is made at 5 mm. In addition, an area 52 (hereinafter, referred to as a second area) 52 closest to the feeding end.
Is colored yellow at 1 mm. Further, an area 53 farthest from the feeding end (hereinafter, referred to as a third area) 53
2.5 mm red hatching. However,
The shape of the feeding end of the middle plate 50 is the same as the shape of the middle plate 13 in the first embodiment described above, and the paper feeding performance is improved as compared with the conventional middle plate as described above.

Here, the first region 51 is located at the rear end regulating plate 15.
When the sheet 54 is placed in a state where is set in accordance with the sheet size, this is an area that looks as shown in FIG. 7A.
Is set according to the sheet size, and the conveyance of the sheet 54 can be surely performed.

As shown in FIG. 6, the second region 52 has a rear end regulating plate 15 of 2.5 to 3.5 mm as described above.
If you place the sheet with it shifted about
This is an area that appears as shown in FIG. 7B. Even if yellow is seen, the sheet can be transported reliably. The first region 51 and the second region 5
Reference numeral 2 denotes a first mark indicating a paper feedable area.

On the other hand, the third area 53 is an area that appears as shown in FIG. 7C when the sheet is placed in a state where the rear end regulating plate 15 is set at a position shifted by 3.5 mm or more. When the red color is seen as described above, a paper feeding failure is likely to occur. The third area 53 is a second mark indicating a non-feedable area.

Therefore, even if an unskilled user does not set the sheet in the third area 53 where the red hatching is visible, that is, take care that the leading end of the sheet enters the green or yellow area. By doing so, it is possible to prevent the occurrence of paper feeding failure.

In the above description, the three regions are divided by color. However, it is needless to say that the same function can be obtained by dividing by three numbers, graduations or patterns.

[0059]

As described above, according to the present invention, the sheet is fed by undulating the sheet feeding side end in a direction perpendicular to the sheet feeding direction to increase the rigidity of the sheet. Even when the feeding end of the next sheet is pressed by the trailing end of the sheet, the deformation of the feeding end of the next sheet can be suppressed. As a result, even if the sheet is set slightly shifted backward, it is possible to prevent the sheet from being jammed, so that an extra burden is not imposed on the user.

Further, since the area of the sheet non-feedable area and the area of the sheet feedable area are displayed at the rotating end of the middle plate, it is assumed that the rear end regulating plate is shifted backward when sheets are stacked. Also, the deviation of the leading end can be immediately recognized, and it is possible to prevent a wasteful paper jam or the like from being caused.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a copying machine that is an example of an image forming apparatus including a sheet feeding device according to a first embodiment of the present invention.

FIG. 2 is a plan view of a paper feed cassette of the paper feed device.

FIG. 3 is an enlarged view of the vicinity of a feeding roller of the paper feeding device.

4 (a) is a sectional view taken along line AA, FIG. 4 (b) is a sectional view taken along line CC, FIG. BB sectional view, GG sectional view, (d) is DD sectional view, EE sectional view.

FIG. 5 is an enlarged view of a main part of FIG. 3;

FIG. 6 is a plan view of a paper feed cassette of a paper feed device according to a second embodiment of the present invention.

FIG. 7 is a view showing how three regions formed at a feeding end of a middle plate provided in the paper feed cassette appear according to a shift of a sheet.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Paper feed roller 12 Separation pad 13 Middle plate 13B Concavo-convex part 14 Spring 15 Rear end regulation plate 29 Paper feed cassette 37 First sheet 38 Second sheet 51 First area 52 Second area 53 Third area

Claims (6)

[Claims] A sheet feeding unit that feeds the sheets stacked and stored in the sheet storing unit, and separates a next sheet fed from the fed sheet along with the fed sheet by a separating unit; A sheet feeding device for feeding a sheet in a direction different from a feeding direction before separation after separation, wherein the sheet storage means is rotatably provided and a middle plate for stacking the sheets, and a middle plate for stacking the sheets. An urging member for urging the middle plate in the direction of the feeding means so as to press the feeding-side end of the fed sheet against the feeding means; and And a concavo-convex portion for making the feeding side end of the sheet pressed against the means undulate in a direction orthogonal to the sheet feeding direction, and undulating the feeding side end of the next feeding sheet. When the fed sheet changes its direction, Paper feeding apparatus being characterized in that so as to suppress the deformation of the feeding end of said next time feeding sheets to be pressed by the part. 2. The uneven portion includes a flat portion formed at a rotating end portion of the middle plate, and a convex portion or a concave portion formed on both sides of the flat portion in a direction orthogonal to a sheet feeding direction. 2. The sheet feeding device according to claim 1, further comprising a concave portion or a convex portion formed on both sides of the convex portion or the concave portion in a direction orthogonal to a sheet feeding direction. And a regulating member for regulating the movement of the stacked sheets by abutting on a side end opposite to a feeding side end of the stacked sheets so as to be movable in a feeding direction. If the sheet is shifted in a direction away from the rotation end of the intermediate plate due to the position of the regulating member, a mark indicating that the sheet is stacked with a deviation is displayed on the rotation end of the intermediate plate. The sheet feeding device according to claim 1, wherein the sheet feeding device is provided with the sheet feeding device. 4. The mark is a first mark that is provided substantially in parallel with a rotating end of the middle plate, and indicates a paper-feedable area, and a paper-feed disabled area is provided closer to the regulating member than the first mark. 4. The sheet feeding / separating apparatus according to claim 3, further comprising a second mark indicating an area. 5. The paper separating apparatus according to claim 4, wherein the first mark and the second mark are displayed in different colors. 6. The sheet feeding device according to claim 1, wherein the diameter of the feeding unit has a predetermined size such that a direction before the separation and a direction after the separation are largely different.