JP2000264460A - Sheet material feeder and processing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure a prescribed paper feeding performance, even if reduced the friction coefficient of separation/feed roller pair by the endurance abrasion and adhesion of paper powder. SOLUTION: A send-out roller 101 sends out superimposed and loaded sheet materials S. A separation/feed roller pair 102 separates and feeds the sent-out sheet materials S one by one. The sent out sheet materials S are carried to the downstream side by a carrier roller pair 125. In this case, a tip detecting sensor 103 detecting the tip of the feed sheet material is arranged on the right upstream side of the carrier roller pair 125 and a CPU 104A monitors the time, when the tips of the sheet materials reach the sensor 103. When the sheet material tips reach the sensor 103 at later than the prescribed time, the CPU 104A controls the send-out roller to send out the paper sheets so that the tips reach the sensor 103.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding apparatus provided in a sheet processing apparatus for performing a predetermined process on sheet materials fed one by one.

[0002] The sheet material processing apparatus referred to here includes:
For example, an image forming apparatus (copier, printer, facsimile, etc.) that forms an image on a recording material (sheet material) fed one by one, or an image of a document (sheet material) fed one by one There is a document image reading device for reading a document.

[0003]

2. Description of the Related Art A sheet material processing apparatus is provided with a sheet material feeding device for separating and feeding sheet materials stacked one by one. There are various types of this sheet material feeding device. One of them is a feeding roller (pickup roller) for feeding the stacked sheet materials, and the sheet fed by the feeding roller. Some include a separating / feeding roller pair that separates and feeds the materials one by one.

[0004] The feed-out roller normally stands by at an upper position away from the stacked sheet materials, and when there is a sheet feeding instruction, descends while rotating in the sheet material feed-out direction, and moves to the uppermost position. The sheet lands on the sheet material at a predetermined pressure.
As a result, the feeding roller feeds out the stacked sheet materials. The feeding by the feeding roller is conventionally performed for a fixed time.

The separation / feed roller pair includes a feed roller that feeds the uppermost sheet material fed by the feed roller, and a retard roller that pushes the other sheet material fed by the feed roller back to the sheet material stacking section. Consists of The retard roller is in contact with the feed roller at a predetermined pressure. This nip pressure is conventionally constant. The drive is transmitted directly to the feed roller, and the drive is transmitted to the retard roller via a torque limiter.

When one sheet material fed by the feeding roller enters the nip of the separation / feed roller pair, the retard roller is driven to rotate by the feed roller rotating in the sheet material feeding direction. Thus, the sheet material entering the nip of the separation / feed roller pair is fed by the feed roller. Also, when a plurality of sheet materials fed by the feeding roller enter the nip of the separation / feed roller pair,
The retard roller rotates in a direction to push back the sheet material.
Accordingly, only the uppermost sheet material is fed by the feed roller, and the other sheet materials are pushed back to the sheet material stacking section by the retard roller.

[0007]

However, in the case of this type of sheet feeding apparatus, there has been a problem to be solved in order to ensure a predetermined sheet feeding performance permanently. that is,
Slip occurs when the friction coefficient of the surface of each roller of the separation / feeding roller pair is reduced due to durable wear, adhesion of paper powder, or the like. In such a case, the feeding sheet material does not reach the predetermined position within the predetermined time, and the predetermined sheet feeding performance cannot be secured.

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of the above circumstances, and a sheet feeding apparatus capable of ensuring a predetermined sheet feeding performance even if the friction coefficient of a separation / feed roller pair is reduced. The purpose is to provide.

[0009]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention provides a feeding roller for feeding out stacked sheet materials and a sheet material fed by the feeding roller. The present invention relates to a sheet material feeding apparatus including: a separation / feed roller pair for feeding; and conveyance means for conveying the sheet material separated and fed by the separation / feed roller pair to a downstream side.

In order to achieve the above object, the present invention provides a leading edge detecting means for detecting a leading edge of a sheet material fed by the separation / feed roller pair at a predetermined position, and the fed sheet material. And a control means for controlling a feeding time of the feeding roller in accordance with a time required for the front end of the feeding roller to reach the front end detecting means.

For example, when the leading edge of the sheet material fed by the separation / feed roller pair reaches the leading edge detecting means for more than a predetermined time, the control means determines that the leading edge of the fed sheet material has not been reached. Control is performed so that the feeding roller performs feeding until reaching the leading end detecting means. Also,
If the leading edge detecting means is disposed upstream of the conveying means, and the leading edge of the sheet material fed by the separation / feed roller pair reaches the leading edge detecting means over a predetermined time, the control is performed. The means controls the feeding roller to feed the sheet until a predetermined time elapses after the leading edge of the fed sheet material passes through the leading edge detecting means.

According to another aspect of the present invention, in order to achieve the above object, a leading edge detecting means for detecting a leading edge of a sheet material fed by the separation / feed roller pair at a predetermined position, and The image forming apparatus further comprises control means for controlling the nip pressure of the separation / feed roller pair in accordance with the time taken to reach the leading edge detection means.

For example, when the leading end of the sheet feeder reaches the leading end detecting means for more than a predetermined time, the control means sets the nip pressure of the separation / feed roller pair higher than the normal nip pressure. Set.

The leading end detecting means is disposed immediately upstream of a conveying means for conveying the sheet material fed by the separation / feed roller pair downstream. The conveying means is a pair of conveying rollers for nipping and conveying the sheet material.

According to another aspect of the present invention, in order to achieve the above object, nip pressure setting means for setting a nip pressure of the separation / feed roller pair, and nip pressure information to be set for the nip pressure setting means are input. It is characterized by having input means to perform.

The sheet feeding apparatus of the present invention is used as a sheet feeding means in a sheet processing apparatus for performing a predetermined process on a sheet fed one by one.

[0017]

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

<First Embodiment> FIG. 1 shows a first embodiment of the present invention.
1 shows a configuration of a sheet material feeding apparatus according to an embodiment.

The sheet feeding apparatus 100A includes a feeding roller (pickup roller) 101 for sequentially feeding sheet materials S stacked on a tray (not shown) or the like from the uppermost sheet material, and the feeding roller 101. A separation / feed roller pair 102 that separates and feeds the fed sheet material S one by one, and a separation / feed roller pair 102
The sensor detects the front end of the sheet material S fed at a predetermined position on the downstream side, and controls the sheet feeding time of the feeding roller 101 in accordance with the situation where the front end detection sensor 103 detects the sheet front end. CPU
104A.

The separation / feed roller pair 102 is a sheet material S
And a retard roller 102-2 that pushes the sheet material S back to the sheet material stacking portion. When one sheet material S fed by the feed roller 101 enters the nip of the separation / feed roller pair 102, the retard roller 102-2 is driven to rotate by the feed roller 102-1 and the feed roller 102-1 is rotated.
02-1 feeds the sheet material S. When a plurality of sheet materials S fed by the feed roller 101 enter the nip of the separation / feed roller pair 102,
The retard roller 102-2 rotates in the reverse direction, the feed roller 102 feeds only the uppermost sheet material, and the retard roller 102-2 pushes the sheet materials other than the uppermost sheet material back to the sheet material stacking unit.

The feed roller 102-1 is fixed at a predetermined position. The retard roller 102-2 is attached to the feed roller 102-1 so as to be able to contact and separate therefrom, and is in contact with the feed roller 102-1 at a predetermined pressure (nip pressure P). A roller shaft 105 of the retard roller 102-2 has a holder member 107 rotatably mounted on a support shaft 106.
Is rotatably supported on the tip side of the camera. The holder member 107 is urged clockwise by a spring (coil spring) 108. The retard roller 102-2 supported on the tip side of the holder member 107 is
The feed roller 102-1 is actuated by the urging force of the spring 108.
At a predetermined pressure.

The roller shaft 109 of the feeding roller 101
Is a holder member 111 rotatably mounted on the roller shaft 110 of the feed roller 102-1.
Is rotatably supported on the tip side of the camera. The holder member 111 is urged in a counterclockwise direction by a spring (coil spring) 112. This holder member 111
A solenoid 1 for raising and lowering the feed roller 101 supported on the tip side of the holder member 111.
13 are connected.

FIG. 1 shows a state in which the feeding roller 101 is lifted away from the uppermost sheet material S and stands by at a standby position. This state is a state in which the solenoid 113 is excited (the solenoid is on). In this case, the plunger 113-1 contracts, and rotates the holder member 111 clockwise. When the solenoid 113 is demagnetized (solenoid off), the holder member 111 rotates counterclockwise due to the urging force of the spring 112, and the feeding roller 101 supported on the tip end side of the holder member 111 Land on the top sheet S. It should be noted that when there is a paper feed command, the solenoid 113 is turned off.

Feed roller 101 and feed roller 1
The drive from the same motor is transmitted to 02-1 and the retard roller 102-2. FIG. 2 shows the configuration of this drive system.

The motor 114 has a feed roller 102-1.
The roller shaft 110 is directly connected to the
Driving is transmitted to 0. The drive transmitted to the roller shaft 110 is transmitted to the relay shaft 119 via the gears 115, 116, 117 and 118, and further transmitted to the universal coupling 1.
20, the roller shaft 10 of the retard roller 102-2
5 and further transmitted to the retard roller 102-2 via the torque limiter 121. Also, the roller shaft 1
Drives transmitted to the gears 10 are gears 122, 123, and 124.
And transmitted to the roller shaft 109 of the feeding roller 101.

In the drive system having the above structure, the motor 11
4 is turned on, the drive is simultaneously transmitted to the feed roller 101 and the feed roller 102-1.
01 and 102-1 rotate in a predetermined direction. At this time, the drive is not transmitted to the retard roller 102-2, and the roller 102-2 is driven to rotate by the rotation of the feed roller 102-1. When the torque becomes equal to or less than the predetermined value, the torque limiter 121 transmits the drive from the motor 114 to the retard roller 102-2, and the retard roller 102-2 rotates in the opposite direction. The motor 114 is turned on when there is a sheet feeding command.

The leading edge detection sensor 103 detects the leading edge of the sheet material immediately upstream of the pair of transport rollers 125 for transporting the sheet material S fed by the separation / feed roller pair 102 downstream.

A characteristic of the sheet feeding apparatus 100A is that the CPU 104A monitors the state of conveyance of the sheet S by the separation / feed roller pair 102, and the feeding time of the feeding roller 101 according to the state of conveyance. The point is to control. Each roller 102-of the separation / feed roller pair 102
In Nos. 1 and 102-2, the friction coefficient μ of the surface is reduced due to durable wear, adhesion of paper powder, and the like. In such a case, the conveyance capability of the separation / feed roller pair 102 is reduced by the slip, and the sheet material S being conveyed by the separation / feed roller pair 102 reaches a predetermined position (the leading edge detection sensor 103). It takes time. In such a case, C
The PU 104 </ b> A controls the feeding roller 101 to feed the sheet material S until the leading edge of the sheet material S being conveyed by the separation / feed roller pair 102 is detected by the leading edge detection sensor 103, and slips. Roller 101 for the sheet material S
Is applied so that the sheet material S reaches a predetermined position within a predetermined time.

The longest time from when the sheet S is picked up to when the leading edge of the sheet S reaches the leading edge detection sensor 103 when no slip occurs in the separation / feed roller pair 102 is, as shown in FIG. a ₀ + t _N. Here, t _N is a time delayed from the basic time t ₀ due to a slip or the like caused by the feeding roller 101. Further, the same time when the slip occurs in the separation / feed roller pair 102, as shown in FIG.
It is t ₀ + t _N + t _S. Also, in this case, the sheet material S
Is the minimum value, Vp ≧ M1 / (t ₀ + t
_N is a + t _S). Here, M1 is the feed roller 10
2-1 is the distance from the nip between the retard roller 102-2 and the tip detection sensor 103.

FIG. 3 shows that a slip occurs in the separation / feed roller pair 102 and the leading end of the sheet material S is detected by the leading end detection sensor 103.
Shows the paper feeding operation when the time until the time reaches t ₀ + t _N + t _S.

FIG. 3A shows the motor 11 in response to a paper feed command.
4 is turned on, the solenoid 113 is turned off, and the feeding roller 101 rotates in a predetermined direction and lands on the uppermost sheet material S. At this time, the feed roller 101 feeds the sheet material S. The feed roller 102-1 is rotating at a predetermined speed V. However, since the friction coefficient μ of the surfaces of the feed roller 102-1 and the retard roller 102-2 is reduced, the retard roller 102-2 immediately feeds. The roller 102-1 is not driven to rotate.

FIG. 3B shows a state in which the leading end of the sheet material S fed by the feed roller 101 is the feed roller 1.
10 shows a state in which the sheet has passed through the nip between 02-1 and the retard roller 102-2. At this point, the retard roller 10
2-2 is driven and rotated by the feed roller 102-1. The sheet material S is conveyed by the conveying force of the feed roller 102-1 and the conveying force of the feeding roller 101. However, at this time, the conveying speed of the sheet material S is somewhat lower than that in the normal state even with the help of the conveying force of the feeding roller 101.
This is due to the friction coefficient μ of the surface of the feed roller 102-1.
Is low, and the reverse rotation force of the retard roller 102-2 acts from the back surface.

FIG. 3C shows a feed roller 102-1.
The state at the time when the leading end of the sheet material S conveyed by the conveying force of the sheet feeding roller 101 and the conveying force of the feeding roller 101 reaches the leading end detection sensor 103 is shown. At this point, the CPU 104A
Turns on the solenoid 113 and turns the feeding roller 10
1 is raised to the standby position. Accordingly, from this point, the sheet material S is conveyed by the conveyance force of only the feed roller 102-1.

FIG. 3D shows a feed roller 102-1.
The state in which the leading end of the sheet material S conveyed with only the conveying force passes through the nip of the conveying roller pair 125 is shown. The conveying speed of the sheet material S being conveyed by the conveying force of only the feed roller 102-1 is lower than the previous conveying speed. However, when the feed roller 102-1 has a certain friction coefficient μ. Before the conveyance of the sheet material S is stopped, the leading end of the sheet material S can sufficiently enter the nip of the conveying roller pair 125 that is located at a short distance from the leading end detection sensor 103. The sheet material S whose leading end enters the nip of the conveying roller pair 125 is nipped and conveyed by the conveying roller pair 125.

In the above-described paper feeding operation of FIG.
In A, when the leading edge of the sheet material reaches the leading edge detection sensor 103, the conveying force of the feeding roller 101 is released. This is because the friction coefficient μ of the feed roller 102-1 has a certain value and the time t ₀ + t _N + t _S is the time of the conditions that a predetermined value or less.

However, under the condition that the friction coefficient μ of the feed roller 102-1 is extremely low and the time t ₀ + t _N + t _S is equal to or more than the predetermined value, the CPU 104A makes the leading end of the sheet material reach the leading end position detecting sensor 103. After a lapse of a predetermined time T _M from the point in time, the feeding force of the feed roller 101 is released (FIG. 5), and control is performed so that the leading end of the sheet material enters the nip of the feeding roller pair 125 reliably. The time T _M here is the time required for the leading edge of the sheet material that has passed the leading edge detection sensor 103 to reach the nip of the pair of transport rollers 125, and at most T _M ≦ M2 (t ₀ + t
The _N + t _S) / M1. Here, M1 is the distance from the nip between the feed roller 102-1 and the retard roller 102-2 to the leading edge detection sensor 103, and M2 is the distance from the leading edge detection sensor 103 to the nip between the transport roller pair 125.

In the case of this configuration, the retard roller 102-2
The feeding force of the feeding roller 101 overcomes the returning force of the feeding roller 101, and the sheet is likely to be in the double feeding state. However, if a plurality of sheet materials in the double feeding state are nipped and conveyed by the feed roller 102-1 and the retard roller 102-2. However, since the sheet material other than the uppermost sheet material is pushed back by the retard roller 102-2 when the feeding force of the feeding roller 101 is released, the sheet material is not fed to the pair of conveying rollers 125.

<Second Embodiment> FIG. 6 shows a second embodiment of the present invention.
1 shows a configuration of a sheet material feeding apparatus according to an embodiment.

A characteristic of the sheet material feeding apparatus 100B is that the CPU 104B monitors the conveyance status of the sheet material S by the separation / feed roller pair 102, and according to the conveyance status, the separation / feed roller pair. The point is to control the nip pressure P of 102. Each roller 102-of the separation / feed roller pair 102
In Nos. 1 and 102-2, the friction coefficient μ of the surface is reduced due to durable wear, adhesion of paper powder, and the like. In such a case, it takes time for the sheet material S being conveyed by the separation / feed roller pair 102 to reach a predetermined position (the leading end detection sensor 103). In such a case, the CPU 104B increases the nip pressure P of the separation / feed roller pair 102 to increase the conveying capacity, so that the sheet material S reaches the predetermined position within the predetermined time.

Here, by changing the urging force of the spring 108 urging the holder member 107 of the retard roller 102-2, the nip pressure P of the separation / feed roller pair 102 can be changed in three stages. Has become. Spring 10
8 is a pulse motor 12 fixed at a predetermined position.
6 is interposed between the holder member 107 and the hook member (gear head) 127 fixed on the output shaft 126-1. When the pulse motor 126 changes the stop position of the hook member 127, the urging force of the spring 108 changes according to the stop position of the hook member 127, and the nip pressure P changes. The CPU 104B controls the pulse motor 126 so that the hook member 127 stops at the three stop positions X1, X2, and X3.

FIG. 7 shows each stop position (nip pressure setting position) of the hook member 127 rotated by the pulse motor 126.

FIG. 7A shows a state where the hook member 127 is stopped at the position X2 at 12:00. The nip pressure P at this time is P2. This nip pressure P2 is a normally set nip pressure.

FIG. 7B shows a state where the hook member 127 is stopped at the position X1 at 11:00. The nip pressure P at this time is P1, which is larger than P2. This nip pressure P1 is equal to the feed roller 102-1 and the retard roller 1
The nip pressure is set when the friction coefficient μ of No. 02-2 decreases.

FIG. 7C shows a state in which the hook member 127 is stopped at the 1 o'clock position X3. The nip pressure P at this time is P3, which is smaller than P2. This nip pressure P3 is a nip pressure set when double feeding is likely to occur.

The position of X1 in FIG. 7B is the home position of the hook member 127. The hook member 127 at the position X1 is connected to the home position switch 12.
Press 8 to switch on. From this home position X1, the hook member 127 rotates clockwise and moves to the position X2 in FIG. 7A or the position X3 in FIG. 7C.

CPU 1 monitoring the state of conveyance of sheet material S being conveyed by separation / feed roller pair 102
04B, when the leading end of the sheet material S reaches the leading end detection sensor 103 within a predetermined time (t ₀ + t _N ) as shown in FIG. 8, the feed roller 102-1 and the retard roller 102-2 are It is determined that the function is normal without a decrease in the friction coefficient μ, the hook member 127 is stopped at the position X2, and the nip pressure P is set to the normal nip pressure P2.

When the leading end of the sheet material S reaches the leading end detection sensor 103 with a delay of time t _S from a predetermined time (t ₀ + t _N ) as shown in FIG. -1 and retard roller 102
-2 determines that the friction coefficient μ is reduced and slips easily, and controls the pulse motor 126 so that the hook member 127 stops at the position of X1, and sets the nip pressure P to the maximum nip pressure P1. I do. Thus, by setting the nip pressure P to the maximum nip pressure P1, no slip occurs between the feed roller 102-1 and the retard roller 102-2, and the leading end of the sheet material S is kept within a predetermined time (t ₀ +
At t _N ), the light reaches the tip detection sensor 103.

FIG. 10 shows the nip pressure P with and without a delay t _S in the time when the leading edge of the sheet material reaches the leading edge detection sensor 103. Here, the nip pressure P when there is a delay t _S is constant at P1, but the nip pressure P may be increased as a linear function as shown by an imaginary line depending on the degree of the delay t _S.

When the CPU 104B determines that the nip pressure P is too large and there is a double feed of the sheet material, the CPU 104B controls the pulse motor 126 so that the hook member 127 stops at the position X3, and Set P to the minimum nip pressure P3.

Whether the double feed is present or not is determined by the leading end detection sensor 103.
Is determined based on the detection information from. To this end, the time from when the leading edge detection sensor 103 detects the leading edge of the sheet material to when the trailing edge of the sheet material is detected is measured, and the time is measured as one sheet material of the same size as the size used. It may be compared with the time when the sensor 103 is on when the sensor passes the tip detection sensor 103. For example, since in the case of the sheet material of A4 size is the leading edge sensor 103 is ON T _P time, a no double feed because at the same time T _P in the case of the detection results shown in FIG. 11, FIG. 12 In the case of the detection result shown in (1), it can be determined that there is a double feed because the time t _PE is long.

FIG. 13 shows the nip pressure P with and without double feed. Here, when the time t _PE is short, it is regarded as an error, and when the time t _PE exceeds the error, the nip pressure P is reduced to P ₃ corresponding to the double feed.

<Third Embodiment> FIG. 14 shows the configuration of a sheet feeding apparatus according to a third embodiment of the present invention.

The characteristic features of the sheet material feeding device 100C are the same as those of the sheet material feeding device 100B.

Here, the nip pressure P of the separation / feed roller pair 102 can be changed in two stages by changing the urging force of the spring 108 that urges the holder member 107 of the retard roller 102-2. Has become.

The spring 108 is interposed between the plunger 130-1 of the solenoid 103 fixed at a predetermined position and the holder member 107. Solenoid 130
The urging force of the spring 108 changes depending on whether the plunger 130-1 contracts or expands, and the nip pressure P changes. When the plunger 130-1 contracts, the spring 1
08 becomes large, and the nip pressure P is set high. When the plunger 130-1 is extended, the spring 1
08 becomes small, and the nip pressure P is set low (normal pressure).

When the solenoid 130 is off, the plunger 130-1 is extended by being pulled by the spring 108. When the solenoid 130 is on, the plunger 130-1 is sucked and contracts to pull the spring 108.
The CPU 104C determines that the leading edge of the sheet material is within a predetermined time (t ₀ +
If it has reached the tip detection sensor 103 at t _N ), the solenoid 130 is turned off to set the nip pressure P to the normal pressure (low pressure). Further, the leading edge detection sensor 1 delays the leading edge of the sheet material by a time t _S from a predetermined time (t ₀ + t _N ).
If it has reached 03, the solenoid 130 is turned on to set the nip pressure P to a high pressure.

In the second and third embodiments, the necessity and necessity of switching the nip pressure P may not be determined based on the result of one sheet feeding, but may be determined based on the results of several sheet feedings.

In the second and third embodiments, the nip pressure P is switched by the control panel and the video I.
It may be performed by input from the input means 131 such as / F.

FIG. 15 shows a sheet feeding apparatus 10 according to the present invention.
1 shows the overall configuration of a copying machine (sheet material processing apparatus) provided with 0A (100B, 100C).

This copying machine is provided with a plurality of paper feeding units. Deck paper feeder 302 and cassette paper feeders 303, 3
05 is that. The sheet material S is fed one by one from one of these sheet feeding units.

Each of the sheet feeding units 302, 303, and 305 has a sheet material feeding device 100A (100B, 100B) of the present invention.
C) is provided.

The sheet material S fed one by one from the paper feeding units 302, 303, and 305 is sent to the registration roller pair 310 in a rotation stopped state. When the leading end of the sheet material abuts the nip of the pair of registration rollers 310 to form a predetermined amount of loop, the movement stops. By the formation of this loop, the skew state of the sheet material S is corrected.

On the other hand, on the photosensitive drum 311 rotating clockwise, an electrostatic latent image of an original image on the platen glass 304 read by the reading optical system 301 is formed. This electrostatic latent image is visualized (toner image) by the toner supplied from the developing device 308.

The sheet material S in which the skew state has been corrected is moved between the photosensitive drum 311 and the transfer charger 312 by a pair of registration rollers 310 which starts rotating at a timing with the toner image on the photosensitive drum 311. It is sent to the transfer unit. Then, the toner image on the photosensitive drum 311 is transferred to the sheet material S passing through the transfer section by the transfer charger 312.

The sheet material S to which the toner image has been transferred after passing through the transfer section is sent to the fixing device 315 by the transport belt 313. Then, the toner image is heated and pressed while passing through the identification attaching device 315, so that the toner image is fixed.

The sheet material S which has passed through the fixing device 315 and has been subjected to the fixing process is discharged onto a discharge tray 319 outside the apparatus by an inner discharge roller pair 316 and an outer discharge roller pair 317.

The copying machine is provided with a two-sided copy mode and a multiple copy mode in addition to the one-sided copy mode (normal mode). When any of these copy modes is selected, the copying machine passes through the fixing device 315. The sheet material S on which the fixing process has been performed is sent to the registration roller pair 310 again through the paths 320 and 326 and the intermediate tray 321.

In this specification, the sheet feeding apparatus of the type in which the stacked sheet materials are sequentially fed from the uppermost sheet material has been described. However, the present invention relates to the stacked sheet materials. It is needless to say that the present invention can be applied to a sheet material feeding device of a type in which the material is sequentially fed from the lowest sheet material. In the case of this method, the sheet material pressing means presses the stacked sheet materials from above with a predetermined pressure, and the feeding roller feeds the sheet material.

[0069]

As described above, according to the present invention,
When the leading edge of the fed sheet material does not reach the specified position within the specified time, the feeding force of the feed roller is applied to the fed sheet material. Even if the separated / feed roller pair is used as it is, the leading end of the fed sheet material will reach the predetermined position within the predetermined time without slipping, and the predetermined paper feeding performance can be secured.

According to the present invention, the nip pressure of the separation / feed roller pair is increased when the leading edge of the fed sheet material does not reach the predetermined position within the predetermined time.
Even if the separation / feed roller pair having the reduced friction coefficient is used as it is, the leading end of the feed sheet material will reach the predetermined position within the predetermined time without slipping, and the predetermined paper feeding performance can be secured.

[Brief description of the drawings]

FIG. 1 is a side view showing the configuration of a sheet material feeding device according to a first embodiment of the present invention.

FIG. 2 is a front view showing a configuration of a drive system of the sheet feeding apparatus of FIG. 1;

FIG. 3 is a side view illustrating the operation of the sheet feeding apparatus of FIG. 1;

FIG. 4 is a diagram illustrating a time taken from a pick-up of a sheet material to a leading edge of the sheet material reaching a leading edge detection sensor when no slip occurs in a separation / feed roller pair.

FIG. 5 is a diagram illustrating a time required from the pickup of the sheet material to the leading edge of the sheet material reaching the leading edge detection sensor when a slip occurs in the separation / feed roller pair.

FIG. 6 is a side view illustrating a configuration of a sheet material feeding device according to a second embodiment of the present invention.

FIG. 7 is a side view showing each stop position (nip pressure setting position) of a hook member for setting the nip pressure of the separation / feed roller pair.

FIG. 8 is a diagram illustrating a nip pressure set for a separation / feed roller pair when the leading edge of a sheet material reaches a leading edge detection sensor within a predetermined time.

FIG. 9 is a diagram illustrating a nip pressure set for a separation / feed roller pair when a sheet material front end reaches a front end detection sensor with a delay from a predetermined time.

FIG. 10 is a view showing a nip pressure when there is a delay in the time when the leading edge of the sheet material reaches the leading edge detection sensor and when there is no delay.

FIG. 11 is a diagram illustrating a state in which the leading edge detection sensor detects no double feed, and a nip pressure set for a separation / feed roller pair in this case.

FIG. 12 is a diagram illustrating a state in which a leading edge detection sensor detects the presence of double feeding, and a nip pressure set for a separation / feed roller pair in this case.

FIG. 13 is a diagram showing nip pressures when there is no double feed and when there is double feed;

FIG. 14 is a side view illustrating a configuration of a sheet material feeding device according to a third embodiment of the present invention.

FIG. 15 is a vertical cross-sectional side view showing an overall configuration of a copying machine (sheet material processing apparatus) provided with the sheet material feeding device of the present invention.

[Explanation of symbols]

 100A, 100B, 100C Sheet material feeding device 101 Feeding roller 102 Separation / feeding roller pair 103 Tip detection sensor (tip detection means) 104A, 104B, 104C CPU (control means) 125 Transport roller pair (transportation means) 126 Pulse motor (Nip pressure setting means) 130 Solenoid (nip pressure setting means) 131 Input means P Nip pressure S Sheet material

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3F343 FA02 FB02 FB03 FB04 FC01 GA01 GB01 GC01 GD01 HA12 HB04 HD16 JA19 JD03 JD09 JD33 KA04 KA16 LA04 LA14 LC11 LC19 LD10 LD11 MA03 MA15 MA33 MA39 MA45 MB03 MB15 MC08 MC12 MC21 MC23

Claims (9)

[Claims] A feeding roller for feeding out the stacked sheet materials; a separation / feed roller pair for separating and feeding the sheet materials fed by the feeding roller one by one; Conveying means for conveying the sheet material separated and fed by the feed roller pair to the downstream side, wherein the leading end of the sheet material fed by the separation / feed roller pair is A leading edge detecting unit that detects at a predetermined position, and a control unit that controls a feeding time of the feeding roller in accordance with a time taken until a leading edge of the fed sheet material reaches the leading edge detecting unit. Characteristic sheet material feeding device. 2. When the leading edge of the sheet material fed by the separation / feed roller pair reaches the leading edge detecting means for more than a predetermined time, the control means determines that the leading edge of the fed sheet material is not sufficient. 2. The sheet feeding device according to claim 1, wherein the feeding roller controls the feeding so that the feeding roller reaches the leading edge detecting unit. 3. The method according to claim 1, wherein the leading end detecting unit is disposed upstream of the conveying unit, and a leading end of the sheet material fed by the separation / feed roller pair reaches the leading end detecting unit for a predetermined time. 2. The control device according to claim 1, wherein the control unit controls the feeding roller to feed the sheet until a predetermined time elapses after the leading edge of the sheet material passes through the leading edge detecting unit. A sheet material feeding device according to item 1. 4. A feed roller for feeding out stacked sheet materials, and a separation / feed roller pair for separating and feeding the sheet materials fed by the feed roller one by one. In the sheet material feeding device, a leading edge detecting means for detecting a leading edge of the sheet material fed by the separating / feeding roller pair at a predetermined position, and a leading edge of the feeding sheet material reaching the leading edge detecting means. A sheet feeding device having control means for controlling a nip pressure of the separation / feed roller pair in accordance with an elapsed time. 5. When the leading end of the sheet material reaches the leading end detecting means for more than a predetermined time, the control means sets the nip pressure of the separation / feed roller pair higher than the normal nip pressure. The sheet feeding device according to claim 4, wherein the setting is performed. 6. The apparatus according to claim 1, wherein the leading end detecting means is disposed immediately upstream of a conveying means for conveying the sheet material fed by the separation / feed roller pair downstream. The sheet material feeding device as described in the above. 7. The sheet material feeding apparatus according to claim 6, wherein said conveying means is a pair of conveying rollers for nipping and conveying the sheet material. 8. A feed roller for feeding out stacked sheet materials, and a separation / feed roller pair for separating and feeding the sheet materials fed by the feed roller one by one. A sheet material feeding device, comprising: a nip pressure setting means for setting a nip pressure of the separation / feed roller pair; and an input means for inputting nip pressure information to be set to the nip pressure setting means. Sheet material feeding device. 9. A sheet material processing apparatus for performing a predetermined process on sheet materials fed one by one, as means for separating and feeding the sheet materials one by one. A sheet material processing apparatus provided with any one of the sheet material feeding apparatuses.