JP2000038229A - Sheet material feeding device and sheet material processing device - Google Patents

Abstract

(57) Abstract: In a sheet material feeding device having two separating means, a predetermined sheet interval is ensured during continuous feeding. A sheet material feeding device (200) sequentially feeds sheet materials (S) loaded in a sheet feeding cassette (201) by a sheet feeding roller (202) in order from a top sheet material. Then, the sheet material S sent out by the feeding roller 202 is separated into one uppermost sheet material by a separation claw 203 and fed. If the sheet is not separated by the separation claw 203, the sheet is separated into one uppermost sheet by the separation roller pair 204 and fed. Feeding is performed at a fixed feed timing, but the information of the sheet material detection sensor 216 is read a predetermined time before the next feed timing, and if the information indicates that there is no sheet material, the feed is performed at the predetermined feed timing. In the case of the information indicating that there is a sheet material, the sheet feeding timing for that time is delayed by a predetermined time from the predetermined sheet feeding timing.

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] Representative examples of the sheet material processing apparatus referred to here include, for example, an image forming apparatus (printer, copier) that forms an image on a sheet material (recording material) fed one by one. , Facsimile, etc.) and a document image reading device for reading an image of a sheet material (document) fed one by one.

[0003]

2. Description of the Related Art A sheet material processing apparatus such as an image forming apparatus or a document image reading apparatus is provided with a sheet material feeding apparatus for separating and feeding stacked sheet materials one by one.

Various types of sheet material feeding devices are used, and among them, one having two separating means having different separation methods for the purpose of enhancing the sheet material separating performance. is there. This means that the first separating means is connected to the second separating means.
The separation means supplements the separation performance. For example, as a typical example, a separation roller pair including a separation claw (first separation unit), a feed roller rotating in the sheet material feeding direction, and a retard roller rotating in the direction opposite to the sheet material feeding direction is exemplified. (Second separating means).

[0005]

When the sheet feeding device continuously feeds a plurality of sheets, a predetermined interval is provided between the preceding sheet and the succeeding sheet. Must be done. This interval, that is, the sheet interval, is necessary for detecting the size of the sheet material being conveyed (the size in the conveyance direction) and the jam with a sensor.
If there is no predetermined sheet interval, a conveyance failure occurs.

However, in the case of the above-described sheet feeding apparatus having the two separating units, when the sheet feeding is controlled at a fixed sheet feeding timing (the sheet stacking position is set as the sheet feeding start position), In some cases, a predetermined paper interval could not be obtained. This is because the leading end position (sheet feeding start position) of the sheet material at the time of starting sheet feeding of the next sheet material occurs depending on whether or not the first separating unit has performed the separating function. That is, when the first separating means has performed the separating function, the leading end of the next sheet material is located at the sheet material loading position, and when the first separating means has not performed the separating function, the leading end of the next sheet material has been removed. Is located between the first separating means and the second separating means. In the latter case, the paper feed timing has been substantially advanced, and a predetermined paper interval cannot be obtained.

[0007] Such a problem can be solved, for example, by setting the paper feed timing time longer, but in this method, there is a problem that the throughput is reduced, which is not practically preferable.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides a sheet feeding apparatus capable of reliably obtaining a predetermined sheet interval without setting a long sheet feeding timing time. The purpose is to provide.

[0009]

In order to achieve the above object, according to the present invention, there is provided a sheet material feeding means for sequentially feeding stacked sheet materials from a top sheet material, and a sheet material delivered by the sheet material sending means. First sheet material separating means for separating the sheet material into one uppermost sheet material, and separating a plurality of sheet materials into one uppermost sheet material downstream of the first sheet material separating means. And a second sheet material separating means.

In order to achieve the above object, the present invention provides a sheet for detecting whether or not a staying sheet material exists between the first sheet material separating means and the second sheet material separating means. And a sheet supply control unit that changes a sheet supply timing according to a detection state of the sheet material detection unit.

The paper feed control means performs paper feed control as follows. That is, the detection state of the sheet material detecting means is checked before the predetermined sheet feeding timing, and when the presence of the staying sheet material is detected, the sheet feeding timing is delayed by a predetermined time from the predetermined sheet feeding timing.

[0012]

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

FIG. 1 shows an overall schematic configuration of an image forming apparatus (laser beam printer) provided with a sheet feeding apparatus of the present invention.

First, the image forming apparatus will be briefly described.

A sheet feeding device 200 of the present invention for separating and feeding the stacked sheet materials S one by one is installed below the image forming apparatus main body 100. This will be described in detail later.

The sheet material S fed by the sheet material feeding device 200 is sent by a pair of conveying rollers 101 to a pair of registration rollers 102 in a rotation stopped state.

The sheet material S sent to the pair of registration rollers 102 stops moving when a predetermined amount of loop is formed by the leading edge of the sheet abutting the nip of the pair of registration rollers 102. By the formation of this loop, the skew state of the sheet material S is corrected.

The sheet material S, which has been corrected for the skew state, has a pair of registration rollers 10 which starts rotating at a predetermined timing.
2, the photosensitive drum 1 rotating clockwise
The sheet is sent to a transfer section between the transfer roller 03 and the transfer roller 104.

The sheet material S sent to the transfer section includes
The toner image on the photosensitive drum 103 is transferred by the transfer roller 104.

A toner image is formed on the photosensitive drum 103 as follows. That is, the laser scanner 105 emits a laser beam L based on image information sent from a host computer (not shown), and irradiates the photosensitive drum 103 rotating clockwise. As a result, an electrostatic latent image is formed on the photosensitive drum 103, and the electrostatic latent image is developed by a toner developing device (not shown).

The sheet material S to which the toner image has been transferred after passing through the transfer section is sent to the fixing device 106. Then, the toner image in the unfixed state is fixed on the sheet surface by being heated and pressed while passing through the fixing nip of the identification attaching device 106.

The sheet material S which has been subjected to the fixing process and has passed through the fixing device 106 is sent to the upper portion of the image forming apparatus main body 100 by a pair of conveying rollers 107, and is discharged onto a discharge tray 109 outside the apparatus by a pair of discharge rollers 108. You.

Next, the sheet feeding apparatus 200 of the present invention will be described in detail. In this description, FIGS.
Is used.

The sheet material feeding apparatus 200 separates the sheet materials S stacked and stored in the sheet feeding cassette 201 one by one in order from the uppermost sheet material to form the image forming apparatus main body 1.
Feed within 00.

In the paper feed cassette 201, a middle plate 206 pushed up by a push-up spring (coil spring) 205 is installed, and a sheet material S is stacked on the middle plate 206. The middle plate 206 rises as the sheet material S decreases. Thus, the height position of the uppermost sheet material is always kept at the same level. The leading end of the uppermost sheet material is in contact with the separation claw 203 that regulates the height position.

The sheet material S loaded and stored in the sheet feeding cassette 201 is a half-moon shaped sheet feeding roller 202.
Sent out by FIG. 2 shows a state at the time of paper feed standby. At this time, the feed roller 202 has stopped rotating at the illustrated home position. Then, in response to the input of the paper feed start signal, the paper feed roller 202 makes one rotation in the counterclockwise direction (the direction of the arrow) to feed the sheet material S by frictional force. The driving of a paper feed motor (not shown) is transmitted to the paper feed roller 202 via a paper feed clutch (not shown). When the feed motor is turned on and the feed clutch is turned on, the drive of the feed motor is transmitted to the feed roller 202.

The sheet material S sent out by the sheet feeding roller 202 is separated and fed into one uppermost sheet material by a separating claw 203 serving as first separating means. Is not exhibited, the sheet is separated into one uppermost sheet by the separation roller pair 204 as the second separating means and fed. Here, when the separation is performed by the separation claw 203, the leading end of the next sheet material is located at the stacking position, but when the separation is performed by the separation roller pair 204 without being separated by the separation claw 203. , The leading end of the next sheet material is located near the nip of the separation roller pair 204.

The separation roller pair 204 is a feed roller 20 which is always rotationally driven in the sheet conveying direction (the direction of arrow a).
4a, usually with the feed roller 204a,
When a plurality of sheet materials S enter the nip of the separation roller pair 204, the retard roller 204b is driven to rotate in a direction (arrow b direction) opposite to the sheet material conveyance direction.

When a plurality of sheets enter the nip of the separation roller pair 204, the sheets other than the top sheet are pushed back by the retard roller 204b, and only the top sheet is fed by the feed roller 204a. Is done.

The feed roller 204a is provided on the image forming apparatus main body 100 side. This feed roller 20
4a, the driving of the feed motor is performed by the feed roller shaft 2;
07. When the paper feed motor is turned on, its drive is directly transmitted to the feed roller 204a. The feed roller shaft 207 is connected to the image forming apparatus body 1.
00 is rotatably supported.

The retard roller 204b is connected to the sheet feeding cassette 2
01 side. This retard roller 204b
, The drive of the paper feed motor is transmitted via the relay shaft 208, the coupling 209, the retard roller shaft 210, and the torque limiter 211. When the paper feed motor is turned on, the drive is transmitted directly to the retard roller 204b. The retard roller shaft 210 is rotatably supported by the swing member 212.

The swinging member 212 is attached to the sheet cassette 201 so as to be rotatable up and down around a support shaft 213, and is rotated clockwise by an urging spring (coil spring) 214. Biased in the direction. Thus, the retard roller 204b is in contact with the feed roller 204a at a predetermined pressure.

Next, parts related to the present invention will be described.

In the case of the present sheet feeding apparatus 200, the position of the leading end of the next sheet after the uppermost sheet S has been fed is determined by the separating claw 203 serving as the first separating means. As described above, it differs depending on whether or not it has been performed.
Therefore, when the sheet feeding is controlled at a fixed sheet feeding timing, the sheet feeding timing of the sheet material whose leading end is already located near the nip of the pair of separation rollers 204 as the second separating means at the start of the sheet feeding is substantially As a result, a predetermined sheet interval cannot be obtained, and the size and jam of the sheet material cannot be detected by the sensor. Therefore, in this case, even if the leading end of the sheet material is already located near the nip of the separation roller pair 204 at the start of sheet feeding, a predetermined sheet interval is obtained.

The sheet feeding apparatus 200 includes the separating claw 20
Sheet detection sensor 21 for detecting whether or not the staying sheet S exists in the path P1 between the sheet roller 3 and the separation roller pair 204.
6 is provided. The sheet material detection sensor 216 includes a photo interrupter 216a and a sensor lever 216b.

The sensor lever 216b is mounted so as to be rotatable up and down around a support shaft 216c, and is normally urged clockwise by an unillustrated urging spring to be at a position shown by a broken line. At this time, the sensor lever 216
b shields the optical path 216d of the photo interrupter 216a from light, and the photo interrupter 216a is in an off state (sheet material is not detected). Then, the sensor lever 216b is lifted by the sheet material S moving on the path P1 and rotates counterclockwise as shown by the solid line. Accordingly, the sensor lever 216b is disengaged from the optical path 216d of the photo interrupter 216a, and the photo interrupter 216a is turned on (sheet material detection).

Accordingly, the next sheet material (retained sheet material) S whose leading end is located near the nip of the separation roller pair 204 without being separated by the separation claw 203 after feeding the uppermost sheet material is the sheet material. It is detected by the detection sensor 216.

Information from the sheet material detection sensor 216 is sent to the CPU (sheet feeding control means) 110 (FIG. 1) for controlling sheet feeding of the sheet material feeding apparatus 200.
Numeral 10 controls paper feed based on information from the sheet material detection sensor 216.

FIG. 4 shows a paper feed control method performed by the CPU 110.

The CPU 110 normally feeds paper at a constant paper feed timing as shown in FIG. 4A, but the information (signals) from the sensor 216 is given a predetermined time (several seconds) before the next paper feed timing. ) Is read, and if the sensor 216 is in the off state, paper feeding is continued at a predetermined paper feeding timing.
FIG. 4A shows a case where the sensor 216 is off in all readings. If the sensor 216 is in the ON state as shown in FIG. 4B, the paper feed timing for that time is delayed by a predetermined time from the predetermined paper feed timing. Here, the delay time of the sheet feeding timing is set to a time required for the leading edge of the sheet material to reach the nip of the separation roller pair 204 from the stacking position.

By performing such control, the sheet material whose leading end is already located near the nip of the pair of separation rollers 204 at the start of sheet feeding can be fed with a predetermined interval.

The timing for reading the information from the sensor 216 is set after the trailing end of the fed sheet has passed the sensor 216. By doing so, it is not necessary to erroneously detect the fed sheet material and the staying sheet material.

Here, the sheet material detection sensor 216 is disposed at a substantially intermediate point between the separation claw 203 and the separation roller pair 204. However, in order to reduce the influence of the sensor lever 216b on the conveyance of the sheet material, Material detection sensor 21
6 is preferably arranged at a position close to the separation roller pair 204.

Here, a sensor for detecting the sheet material in contact with the sheet material is used as the sheet material detecting means.
If a sensor that detects the sheet material without contacting the sheet material (for example, a reflection type optical sensor, a transmission type optical sensor, etc.) is used, the back tension by the sensor is not applied,
The conveyance of the sheet material is stabilized.

[0045]

As described above, according to the present invention,
The information from the sheet material detecting means for detecting whether or not a stagnant sheet material exists between the first sheet material separating means and the second sheet material separating means is provided a predetermined time before a predetermined feeding timing comes. When the information is read and there is a staying sheet material, the current sheet feeding timing is delayed by a predetermined time from the predetermined sheet feeding timing, so that the sheet leading end is already close to the second separating means at the start of sheet feeding. Even a positioned sheet material can be fed with a predetermined space between sheets.

Therefore, the size and jam of the sheet material cannot be detected by the sensor, and the reliability of the apparatus is improved.

Further, since it is not necessary to set a long paper feed timing time in order to obtain a predetermined paper interval, the throughput does not decrease.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an overall schematic configuration of an image forming apparatus (laser beam printer) including a sheet material feeding device of the present invention.

FIG. 2 is a cross-sectional view illustrating a configuration of a sheet material feeding device according to the present invention.

FIG. 3 is a development view showing a configuration of a separation roller pair.

FIG. 4 is a timing chart showing a paper feed control method.

[Explanation of symbols]

 110 CPU (paper feed control means) 200 sheet material feeding device 202 paper feed roller (sheet feed means) 203 separation claw (first sheet material separation means) 204 separation roller pair (second sheet material separation means) 216 sheets Material detection sensor (sheet material detection means) S Sheet material

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G03G 21/14 G03G 21/00 372 F term (Reference) 2C059 AA00 AA05 AA09 AA53 AA61 2H027 DC03 ED17 2H072 AA12 AA22 AB00 BA12 3F343 FA02 FB02 FB03 FB04 FC03 GA03 GB01 GC01 GD01 HB03 HD18 JA03 JD09 JD11 MA03 MA13 MA14 MA23 MA54 MB04 MB13 MC08 MC23

Claims (7)

[Claims] A first sheet material feeding means for sequentially feeding the stacked sheet materials from a top sheet material; and a first sheet material for separating the sheet material sent by the sheet material sending means into one top sheet material. A sheet material separating means, and a second sheet material separating means for separating a plurality of sheet materials into one uppermost sheet material on the downstream side of the first sheet material separating means. In the material feeding apparatus, a sheet material detecting means for detecting whether or not a stagnant sheet material exists between the first sheet material separating means and the second sheet material separating means, and the sheet material detecting means And a sheet feeding control means for changing a sheet feeding timing according to a detection state of the sheet feeding device. 2. The sheet feeding control means checks a detection state of the sheet material detecting means before a predetermined sheet feeding timing, and when the presence of a stagnant sheet material is detected, the sheet feeding timing is determined by a predetermined time. 2. The sheet feeding device according to claim 1, wherein the sheet feeding device is delayed by a predetermined time from the sheet feeding timing. 3. The method according to claim 1, wherein the first sheet material separating means separates using a buckling strength of the sheet material, and the second sheet material separating means pushes back and separates other than the uppermost sheet material. The sheet material feeding device according to claim 1, wherein the sheet material feeding device is a system. 4. The apparatus according to claim 3, wherein a separation claw is used for the first sheet material separation means, and a separation roller pair is used for the second sheet material separation means.
A sheet material feeding device according to item 1. 5. The sheet material feeding device according to claim 1, wherein the sheet material detecting means detects the sheet material by contacting the sheet material. 6. The sheet material detecting means according to claim 1, wherein said sheet material detecting means detects the sheet material without contacting the sheet material.
A sheet material feeding device according to item 1. 7. A sheet material processing apparatus for performing a predetermined process on sheet materials fed one by one as sheet material feeding means for separating and feeding the stacked sheet materials one by one. A sheet processing apparatus comprising the sheet feeding apparatus according to any one of claims 1 to 6.