JPH05338825A - Paper feeding device - Google Patents

Abstract

PURPOSE:To reduce stains of paper sheets caused by formed images, and enable the stable paper feeding without shortage of the carrying force and uneveness. CONSTITUTION:A feed roller 130 to constitute a paper separating part and a feeding roller 120 to feed the lowerst paper sheet to a separate roller 131 are made to be an elastic body of high friction resistance having a plurality of tops forming acute angle, and the pressure applying contact are with the paper sheet is reduced while the carrying force is maintained.

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 copying machine, a printer and a facsimile machine.

[0002]

2. Description of the Related Art When the page order of a copy to be made is matched with a double-sided device of a copying machine, or when the copy processing speed is improved by combining it with an RDH (original circulation type automatic document feeder), The bottom paper feeding method is adopted.

As in the image forming apparatus disclosed in Japanese Patent Application Laid-Open No. 63-41329, generally, in lower paper feeding, a lowermost paper of the stacked paper is sent to the separating section, and a sending roller is arranged below the stacking tray. A pressurizing unit is provided for urging the stacked sheets toward the delivery roller.

[0004]

In the above-mentioned conventional double-sided device or the like, since the paper on which one side has been copied is handled, it is necessary to use the paper shown in FIG.
As shown in (a), when the sheet is fed downward with the image side facing downward, the back side of the first sheet P ₁ is the second sheet P ₂
However, since the first sheet P ₁ is being conveyed, the stain is dispersed and slight.

However, as shown in FIG. 14B, when the image surface of the sheets is stacked upward (face up) and the sheets are fed one by one from the bottom, the back side of the second sheet P ₂ is the first sheet. There is a problem in that the toner on the P ₁ image is liable to be contaminated due to the toner falling off.

In order to deal with this problem, it is best to improve the fixing property of the toner. However, if that is not possible, the pressing force P _A is often reduced to deal with it. However, thick paper or the like generally has a low fixing property, so that stains occur, and the feeding force becomes insufficient, so that there is a limit in reducing the pressing force P _A.

Further, in the conventional double-sided device or the like, the upper surface of the stacked sheet bundle is not flat due to curling and corrugation of the sheet. Further, in the case where a plurality of delivery rollers are arranged side by side in the direction perpendicular to the transport direction, the contact between the delivery roller and the sheet may not be uniform due to variations in the roller itself or the mounting accuracy of the rollers. is there.

For this reason, the pressure acting between the sheet bundle and the delivery roller becomes non-uniform in the width direction of the delivery roller, and if the paper is fed in this state, skew or non-feeding is likely to occur. ..

The object of the present invention is to reduce the stain on the paper due to the formed image, and to prevent the conveyance force from being insufficient and uneven.
An object of the present invention is to provide a paper feeding device that can perform stable paper feeding.

[0010]

SUMMARY OF THE INVENTION The above-mentioned object is to stack and store single-sided image-formed sheets with the image side facing up, and separate them one by one from the bottom sheet side of the sheet bundle by frictional force. In a paper feeding device for feeding paper, a paper conveying means which is provided below a stacked paper sheet and is made of a high-friction elastic body having a plurality of substantially acute-angled tops for feeding the bottommost paper, and above the paper conveying means. And a sheet pressing means for pressing and urging the sheet bundle toward the sheet conveying means. The weight of the sheet bundle and the pressure action between the sheets generated by the sheet pressing means are applied to the top of the sheet conveying means. It is achieved by being configured so as to be dispersed and acted on the range of the paper surface of a certain area with the rotational movement of.

A further object of the present invention is to provide a sheet feeding device that separates sheets one by one from the bottom sheet side of the stacked sheets by frictional force and feeds the sheets, which is provided below the stacked sheets and sends out the bottom sheet. A plurality of sheet-conveying means made of high-friction elastic body for arranging them in a direction perpendicular to the sheet-conveying direction, and arranged above the sheet-conveying means so as to face each other. A sheet pressure plate for pressing and urging toward the plurality of sheet conveying means, and further, the sheet pressure plate has a fulcrum at the center of the plurality of sheet conveying means in the width direction and is swingable by a predetermined amount. It is achieved by supporting.

[0012] Further, the above-mentioned object is that in the paper feeding device for separating and feeding the stacked sheets of paper one by one from the bottom sheet side by frictional force, the bottom sheet provided below the stacked sheets is fed. A sheet conveying means made of a high friction elastic body for sending out,
A sheet pressure plate which is disposed above the sheet conveying means to face the sheet bundle, and which presses and urges the sheet bundle; a contacting / separating means which presses and separates the sheet pressure plate onto the sheet bundle; This is achieved by providing a restricting means for restricting the most lowered position and an urging means for urging the sheet pressure plate around the support shaft so that the pressing urging force is reduced in accordance with the decrease of the sheet bundle.

[0013]

Even when the sheets on which one side of the image has been formed are stacked and stored with the image side facing upward, the sheet conveying means is provided below the stacked sheets and has a high-friction elastic body having a plurality of substantially acute-angled tops. Therefore, the pressure contact area with the sheet at the time of sheet feeding is small, the occurrence of stains on the sheet due to the formed image is small, and further, since the sheet comes into elastic contact with the sheet to be fed, the reduction of the conveying force is suppressed.

Further, as a result of the paper pressure plate being pivotally supported by a predetermined amount in the direction of the paper conveying means, the pressing force in the width direction of the paper conveying means is equalized, so that no pressure is applied during paper feeding. Skewing and non-feeding due to uniformity are prevented in advance.

Further, since the means for restricting the lowermost position of the pressure plate is provided, it is possible to prevent the sheet from being excessively pressed by the sheet pressure plate and deformed when the amount of the sheet bundle is reduced. , It can be fed smoothly even under the condition that the amount of paper is small.

[0016]

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

FIG. 2 is a block diagram of a double-sided device of a copying machine.
In the figure, a double-sided device 100 is an intermediate tray 101.
A conveying roller 102 provided on the downstream side of the intermediate tray 101 in the conveying direction, a stopper 103 further provided on the downstream side of the intermediate tray 101, and a sheet conveying device that is provided on the lower surface side of the intermediate tray 101 and sends out the sheet on the intermediate tray 101. It is mainly composed of a delivery roller 120 (which will be described in detail later) as a means.

By transferring the image on the photosensitive drum 1, the paper 2 which has been copied on one side is fixed by the fixing device 3, the branching claw 4,
It is fed into the double-sided device 100 through the switch back device 5. The sheet 2 carried into the double-sided device 100 is discharged and stored on the intermediate tray 101 from the discharge gates A1 to A4 which are predetermined according to the sheet length in the transport direction.
That is, the long letter is emitted from the A1 side and the short letter is emitted from the A4 side. The discharged sheet 2 slides on the already stored sheet 2, is further conveyed by the conveying roller 102, and collides with the stopper (stopper gate means) 103 to align the advancing edges of the sheet.

When a predetermined number of sheets of paper 2 are stored, the stopper 103 makes one turn around the support shaft 104, and the conveying path is opened. After that, the delivery roller 120 rotates to convey the entire sheet bundle 200 to the separation roller pair 105 on the downstream side, and the separation roller pair 105 separates only one sheet of the bottom sheet and feeds it, and the sheet is sent from the double-sided device 100. To be done.

FIG. 1 is a detailed configuration diagram of a main portion of a re-feeding device according to an embodiment of the present invention, and FIG. 3 is a main-portion configuration diagram showing a state of the re-feeding device at the time of separate sheet feeding.

The carrying roller 102 is made of a material having a relatively low coefficient of friction, and is supported by a supporting arm 107.
The support arm 107 is further suspended from the drive shaft 108. A belt 109 is stretched between the drive shaft 108 and the conveyance roller 102 via a pulley, and rotates the conveyance roller 102 counterclockwise. The discharged sheet 2 is conveyed by the conveying roller 102 to the abutting surface 103a of the stopper 103, and after the sheet abutting, the conveying roller 102 slips on the sheet 2 so that the sheet 2 abutted against the abutting sheet 2 is conveyed. There is no buckling. Further, as the number of sheets of paper 2 accommodated increases, the transport roller 102 can move upward about the shaft 108.

The stopper 103 comprises a feed roller 130 and a separate roller 13 which form a separation roller pair 105.
It is arranged upstream of the separation nipple (nip portion) N formed by 1, and the abutting surface 103 a of the solenoid 106 advances and retreats from the conveyance path by the solenoid 106.

A plurality of delivery rollers 120 are provided below the retransmission side of the intermediate tray 101. The feed-out roller 120 is made of a triangular or polygonal high-friction elastic body (for example, soft rubber or sponge rubber) having a substantially acute-angled top portion, and the surface thereof when the paper is accommodated is the intermediate tray 10.
Although the sheet bundle 200 is retracted downward from the conveyance surface of No. 1, the outer periphery of the intermediate tray 101 pops out from the opening 101a on the intermediate tray 101 and comes into contact with the bottom sheet when the sheet is retransmitted. Transfer to the separation roller pair 105. The delivery roller 120 is a clutch 113 that is controlled to rotate once.
Driven by.

The bundle of sheets 200 is supported by a support shaft 114 above the re-sending end, and is swingably controlled by a solenoid 116 which is a contacting / separating means with the support shaft 114 as a center. A pressure plate 115 is provided. Pressure plate 1
15 is an upper guide plate 110 as shown in FIG.
Although it is retracted inside, when it is retransmitted, the sheet bundle 200 is sent out from the opening 110a onto the uppermost sheet in accordance with the rotation of the delivery roller 120, and the sheet bundle 200 is pushed and biased toward the roller 120 side.

The sheet separating portion is fed by a feed roller 130 driven in the feeding direction, a separate roller 131 which is pressed against the feeding roller 130 and is driven in the counter feeding direction by a torque limiter (not shown), and an upper guide. It is composed of a plate 110, a lower guide plate 111, and the like. Nip portion N of feed roller 130 and separate roller 131
When there is one sheet 2 and when there is no sheet 2, the torque limiter slides and the separate roller 131 rotates with the feed roller 130. Note that reference numeral 132 is a pair of conveying rollers.

The sheet 2 sent out from the sheet separating section is carried out by the carrying roller pair 132. Between the upstream side of the separation nipple N and the downstream side of the stopper abutment surface 103a, preferably at a position close to or less than 20 mm from the separation nipple N, a feed amount regulating member 150 inclined in the same direction as the stopper abutment surface 103a is provided, A gap 151 for allowing a regulated amount of paper to pass and a space 151 for reducing pressure are provided between the lower end of the feed amount regulating member 150 and the lower guide plate 111.

The material of the separate roller 131 is
A material having a friction coefficient slightly smaller than that of the feed roller 130 is selected. That is, when the friction coefficients between the feed roller 130 and the paper, between the separate roller 131 and the paper, and between the papers are μ ₁ , μ ₂ , and μ _P , μ ₁ > μ ₂ > μ _P The material of both rollers is selected so that For example, a soft rubber material for the feed roller 130,
Further, it is preferable to use foamed polyurethane rubber for the separate roller 131.

FIG. 4 is a cross-sectional view of the first delivery roller portion, FIG. 5 is a side view of the delivery roller portion, and FIG. 6 is an explanatory view of the drive portion of the first delivery roller portion. A first delivery roller portion and a second delivery roller portion (not shown) are provided in front of and behind. Two delivery rollers 120 are provided on the first delivery roller shaft 121 symmetrically with respect to the transport center line L. Each delivery roller 12
In No. 0, a high-friction elastic body 122a having a substantially triangular cross section formed by cutting off a part of a cylindrical body is mounted on the hub 122b. A pulley 123 and a spring clutch 125 are provided at the end of the first delivery roller shaft 121,
A belt 124 is stretched around the pulley 123, and the second delivery roller is synchronously rotated in the same direction. The spring clutch 125 is a drive clutch cylinder integrated with the gear 125a,
A driven clutch cylinder 125b fixed on the shaft 121, a clutch spring 125c wound around both the clutch cylinders, and a sleeve 125d having a protrusion. One end of the clutch spring 125c is the sleeve 125d and the other end is the driven clutch cylinder. It is locked to 125b.

A solenoid 129 for controlling the clutch 125 is provided adjacent to the spring clutch 125. The solenoid 129 is a spring clutch 125.
The engaging claw 128 that engages and disengages with the is operated. When the feeding roller 122 is not fed, the plane portion of the feeding roller 122 faces upward and is retracted below the intermediate tray transport surface. Note that 126 and 12
Reference numeral 7 is a gear meshing with the gear 125a.

FIG. 7 is a sectional view of the pressure plate (paper pressure plate) portion, FIG. 8 is a side view of the central portion of FIG. 7, and FIG. 9 is an explanatory view of the drive unit of the pressure plate. Spindle 1
A pressure plate 115 is provided which is supported by 14 and whose swing is controlled by a solenoid 116 about this. Pressure plate 1
Reference numeral 15 has two pressing portions 115a, which are arranged to face the delivery roller 120. The pressing portion 115a of the pressure plate 115 retracts into the upper guide plate 110 when the sheet is not fed.

A bracket 114a is welded to the support shaft 114, and the bracket 114a and the pressure plate 115 are the spacers 1.
When the pressure plate 115 descends on the sheet bundle, the equalizing function is provided to the two pressing portions 115a, 115a, which are rotatably mounted around the center of the sheet bundle 16 and equalize the biasing force. Have

The lower surface of the pressure plate 115 is a smooth surface having a low friction coefficient. Reference numeral 115b is a stopper long hole for restraining excessive movement of the pressure plate 115. The pressure plate support shaft 114 extends to the outside of the upper unit side plate, and an arm 160 is fixed to the shaft end thereof as shown in FIG. The arm 160 is given a habit of turning counterclockwise by a spring 161 which is a biasing means. The force of the spring 161 also applies a sheet pressing force to the pressure plate 115.

On the other hand, the swing lever 162, which is rotatably supported by the side plate of the main body, swings by a fixed angle by the solenoid 116 via the link 163. One end 162a of the swing lever 162 extends in the direction of the arm 160 and engages with a locking pin 160a on the arm 160. 164 is a swing lever 1
The return spring that urges 62 counterclockwise,
Since the return force of the spring 164 is set to be larger than the arm turning force of the spring 161, the arm 160 is rotated clockwise when the solenoid 116 is off. That is, the pressure plate 115 is in the retracted position.

Reference numeral 165 is an adjustable stopper which is a regulating means for regulating the movement of the locking pin 160a. The stopper 165 regulates the lowermost position of the pressure plate 115, and prevents the sheet from being unnaturally pressed and deformed due to the pressure plate 115 being lowered when, for example, there is one remaining sheet. To do. As shown in FIG. 7, the lowest position of the pressure plate 115 may be restricted by the flange portion 122c of the hub 122b.

Next, the operation from the storage of a predetermined number of sheets in the intermediate tray 101 to the re-feeding will be described with reference to the timing chart of FIG.

When the solenoid 106 is turned on, the stopper 103 retracts upward. At the same time, the speed switching solenoid (not shown) is turned on (the speed switching device is not shown).

Next, the delivery roller solenoid 12
9 and the pressure plate solenoid 116 are turned on, the feed roller 120 makes one rotation at a low speed by the one rotation clutch 113, and the pressure plate 116 descends onto the sheet, so that the sheet bundle 200 is moved in the separation nip N direction. To be done. On the way, the upper member of the sheet bundle 200 is restricted from being transported by the restricting member 150 and stopped, and only the lower member continues to reach the separation nip N.

Then, the speed switching solenoid 121 is turned off (which allows the delivery roller 120 to rotate at a normal rotation speed).

Then, the delivery roller solenoid 129 and the pressure plate solenoid 116 are turned on again. At the same time, a separate roller clutch (not shown) is turned on, the separate roller 131 is rotated at a low speed in the counter feeding direction, and the sheet that has entered the separation nip N is slightly returned (at this time, the feed roller 130 is in a rotation free state).

After a short time (time t), a feed roller clutch (not shown) is turned on, the lowermost sheet is fed by the feed roller 130, and the upper sheet is fed by the separate roller 131. Therefore, the progress is blocked (see FIG. 3).

The sheet bundle 200 has a pair of grip rollers 132.
After that, the feed roller clutch and the separate roller clutch are turned off and the driving is stopped. The feed roller 130 is rotated together with the paper by the one-way clutch.

After that, the above steps are repeated.

In this way, the lower layer paper is fed one by one. At the time of feeding the last sheet of the lower layer paper, a part or all of the upper layer portion which is blocked by the regulating member 150 moves in the separating nipple N direction together with the final sheet of the lower layer paper, and the sheet bundle 200 is moved to the separating nipple N portion. It will be automatically replenished.

Here, when the delivery roller 120 is a half-moon roller as in the conventional case, as shown in FIG.
When P _A is the pressing force of the sheet by the pressure plate 115 and P α is the reaction force due to the weight of the sheet bundle, and when the bottom sheet is P ₁ and the sheet next to the bottom sheet is P ₂ , the sheet intervals P _{1 to} P ₂ are The maximum pressure that acts is P _A + P α, which occurs at point Q. The circumference of the circle remains unchanged until the passage. For this reason, as described above, the portion of the back surface of the second sheet P ₂ facing the point Q is significantly soiled as compared with the other portions, which causes a practical inconvenience. Incidentally as the P _A is larger, also dirt becomes conspicuous as the load of the sheet is increased.

On the other hand, in this embodiment, FIG.
Consider a case where the delivery roller 120 has a substantially triangular shape as shown in the operation explanatory diagram of the delivery roller in (c).
The first top portion T1 contacts the sheet bundle 200 at the upstream side L ₁ from the point Q, and a reaction force Pα is generated on the lowermost surface of the sheet bundle. As the delivery roller 120 rotates, the reaction force Pα is shown in FIG.
As shown in (a) to (c), the action point moves with respect to the second sheet P ₂ and disappears at the downstream side L ₂ of the point Q. Subsequently, the second and third tops T2 and T3 are similarly transported.

Therefore, from the viewpoint of the generation of stains, since the stains are dispersed in the area of L ₁ + L ₂ including the Q point of the second sheet P ₂ , the stains are reduced and it is sufficiently practical.
Especially when the load of paper is increased, the effect is obvious.

Further, each top T1 of the delivery roller 120
The angle φ of T3 to T3 is an acute angle, preferably 30 to 80 degrees, and a flat portion of 1 to 10 mm is provided at the tip in consideration of wear resistance. In the case of a small-diameter roller, a <b1,
b2 is recommended.

The number of tops of the delivery roller 120 is not limited to three, and as shown in FIGS. 13 (a) and 13 (b),
Any number of rollers may be used according to the diameter of the delivery roller 120.

Further, if the contact area between the pressure plate 115 and the sheet bundle 200 is increased, the P _A becomes a distributed load, which is more effective in dispersal of dirt.

[0050]

According to the first aspect of the invention, since the plurality of substantially acute-angled tops of the sheet conveying means come into contact with the sheet, the pressure contact area is reduced, and the sheet is prevented from being contaminated by the formed image. Moreover, since the sheet conveying means is made of a high friction elastic body, it is possible to suppress the reduction of the conveying force.

According to the second aspect of the invention, since the paper pressure plate is swingable in the width direction of the paper conveying means, the pressing force in the width direction can be equalized, and skew and non-feeding can be prevented. ..

According to the third aspect of the invention, even if the sheet pressure plate is excessively pressed by the sheet, the regulating member prevents the sheet from deforming, so that the sheet can be smoothly fed without being affected by the amount of the sheet. it can.

[Brief description of drawings]

FIG. 1 is a detailed configuration diagram of a main part of a re-feeding device according to an embodiment of the present invention.

FIG. 2 is a configuration diagram of a double-sided device of a copying machine.

FIG. 3 is a main-part configuration diagram showing a state of the re-feeding device at the time of separate feeding.

FIG. 4 is a cross-sectional view of a first delivery roller portion.

FIG. 5 is a side view of a delivery roller.

FIG. 6 is an explanatory diagram of a drive unit of a delivery roller unit.

FIG. 7 is a sectional view of a pressure plate portion.

8 is a side view of the central portion of FIG. 7. FIG.

FIG. 9 is an explanatory diagram of a drive unit of a pressure plate.

FIG. 10 is a timing chart of a sheet feeding operation.

FIG. 11 is an explanatory diagram of paper feeding by a half-moon-shaped feed roller.

FIG. 12 is an explanatory diagram of sheet feeding by a delivery roller according to the present exemplary embodiment.

FIG. 13 is a diagram showing a modified example of a delivery roller.

FIG. 14 is an explanatory diagram of a conventional paper feeding state.

[Explanation of symbols]

 115 Pressure Plate (Paper Pressing Means) 116 Solenoid (Contact / Separation Means) 120 Feeding Roller (Paper Conveying Means) 130 Feed Roller 131 Separate Roller 161 Spring (Biasing Means) 165 Locking Pin (Regulating Means)

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location B65H 83/02 7111-3F G03G 15/00 309 7369-2H

Claims (3)

[Claims] 1. A paper feeding device for feeding and receiving single-sided image-formed paper sheets, with the image surface facing upward, and separating and feeding the paper sheets one by one from the bottom paper side of the paper sheet by frictional force. A sheet conveying means which is provided below the stacked sheets and which is made of a high-friction elastic body having a plurality of substantially acute-angled tops for feeding the bottom sheet, and a sheet bundle arranged above the sheet conveying means to convey the sheet bundle. A sheet pressurizing means for pressing and urging the sheet in the direction of the means, and the pressure action between the sheets caused by the weight of the sheet bundle and the sheet pressurizing means has a constant area with the rotational movement of the top of the sheet conveying means. A sheet feeding device, which is configured to be dispersed in the range of the sheet surface of the sheet. 2. In a paper feeding device for feeding paper one by one from the bottom paper side of the stacked paper sheets by frictional force, the paper feeding device is provided below the stacked paper sheets and has a height for feeding the bottom paper sheet. A plurality of sheet conveying means made of a friction elastic body and arranged side by side in a direction perpendicular to the sheet conveying direction, and a sheet bundle arranged above the sheet conveying means so as to face each other. A sheet pressure plate for urging the sheet in the direction of the conveying means, and further, the sheet pressure plate has one fulcrum in the widthwise center of the plurality of sheet conveying means and is pivotally supported by a predetermined amount. Paper feeding device characterized by. 3. A paper feeding device for separating and feeding the stacked sheets of paper one by one by frictional force from the side of the bottom sheet, and feeding the bottom sheet provided below the stacked sheets. A sheet conveying means made of a high-friction elastic body, a sheet pressure plate disposed above the sheet conveying means so as to oppose the sheet bundle, and the sheet pressure plate is pressed against and separated from the sheet bundle. Contacting / separating means, a restricting means for restricting the lowermost position of the paper pressure plate, and a biasing means for biasing the paper pressure plate around the support shaft so that the pressing biasing force is reduced according to the decrease of the sheet bundle. And a biasing means.