JPH11263460A - Sheet feeder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet feeder capable of carrying sheets of different thickness by automatically separating them and automatically correcting biased delivery of the sheets in simple constitution. SOLUTION: This device has a delivery roller 5 having a comb teeth type grooves and a separation roller 6 making a pair with each other, center distance variation mechanisms M3, 19, 20a, 20, 21 of this roller pair and sheet detection means 14, 15, biased delivery is corrected by striking a fed sheet 22 against a surface on which the delivery roller 5 and the separation roller 6 are overlapped with each other, and the sheet is delivered by moving the delivery roller 5 and the separation roller 6 to separate from each other. When it is detected that the fed sheet passes between the delivery roller 5 and the separation roller 6, the delivery roller 5 and the separation roller 6 come to be in a state impossible to feed paper. Biased delivery correction and one sheet separation are carried out by the delivery roller 5 and the separation roller 6 by carrying out the aforementioned motion for each of the sheets.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an image forming apparatus such as a rotary type camera, a facsimile machine, a printing machine, a copying machine, a printer, a word processor, etc., and various kinds of automatic document feeders, punches, paper binding machines and the like. Sheets such as cards, thin papers, etc. (sheets such as originals, transfer paper, photosensitive paper, electrostatic recording paper, thermal paper, printing paper, printing paper, OHP sheets, envelopes, postcards, etc.) And a sheet feeding apparatus for feeding one sheet to a sheet processing unit such as an image forming unit, an exposure unit, and a processing unit.

[0002]

2. Description of the Related Art Heretofore, as a sheet separating mechanism of a sheet feeding apparatus for separating and conveying stacked sheets one by one, a type using a pair of comb-like rollers is known.

[0003] In this method, two comb-shaped rollers each having a comb-shaped groove formed on the outer periphery thereof are substantially parallel to each other in a state where the concave and convex surfaces of the grooves overlap each other in the axial direction without contact. The rollers are arranged so as to face each other, and one roller is used as a feed roller to increase the frictional force on the sheet, and the other roller is used as a separation roller to reduce the frictional force against the sheet as compared with the above-described feed roller. The separation roller rotates in the reverse direction of the paper feed, and feeds the sheet to the nip (engagement part) of this roller pair. Even if multiple sheets are fed to the nip, the only sheet that comes in contact with the feed roller is fed. By the feed force of the feed roller rotating in the forward direction, regardless of the separation roller rotating in the reverse direction of the paper feed, the sheet passes through the nip portion, and the other sheets are separated by the separation roller rotating in the reverse direction of the paper feed. By conveying it to prevent entry into or passage of the nip portion, in which only that one separated conveyed sheet in contact with the feed roller.

Further, when the sheets are separated and conveyed one by one, a movable guide plate provided on one or both sides of the sheet is moved to prevent skew, and the skewed sheet side is guided by the guide. There is a mechanism that performs correction by pressing against a plate, or a mechanism that detects skew of a sheet being conveyed using a sensor and drives and rotates the conveyance roller by the amount of skew as necessary to perform correction. Have been.

FIG. 9A is a schematic configuration diagram of an example of a sheet feeding apparatus using a pair of comb-like rollers as a sheet separating mechanism.

Reference numeral 1 denotes a paper feed tray on which sheets 2 are placed.
00 is loaded and set in a predetermined manner. The sheet feeding tray 1 is controlled to swing up and down between a sheet feeding position indicated by a solid line and a standby position indicated by a two-dot chain line.

Reference numerals 2 and 3 denote an upper guide plate and a lower guide plate which constitute a sheet conveying path. The sheet feeding tray side of the lower guide plate 3 is bent downward in front of the tip side of the sheet feeding tray 1 to form a sheet tip abutting plate portion 3 a for aligning the position of the tip end face of the sheets stacked on the sheet feeding tray 1. .

Reference numeral 4 denotes a paper feed roller, which picks up and feeds the sheets 200 stacked and set on the paper feed tray 1.

Reference numerals 5 and 6 denote a roller pair of a feed roller and a separation roller, which are disposed downstream of the paper feed roller 4 in the sheet conveying direction. The feed roller 5 is an upper roller and the separation roller 6 is a lower roller.

Both the feed roller 5 and the separation roller 6 are provided with a comb-shaped roller having a comb-shaped groove formed on the outer periphery as shown in a perspective view of FIG. The convex surfaces are arranged so as to be substantially parallel to each other so as to overlap each other in a non-contact manner in the axial direction. The frictional force of the feed roller 5 on the sheet is greater than the frictional force of the separation roller 6 on the sheet.

Reference numeral 16 denotes a registration roller, and reference numeral 17 denotes a transport roller, which are sequentially disposed downstream of the pair of feed rollers and separation rollers 5 and 6 in the sheet transport direction.

The feed roller 4 is driven from the first motor M1 by a pulley 12 → a belt 11 → a two-stage pulley 10 → a belt 8
→ Receiving power transmission via the pulley 4a, the sheet is rotated in the clockwise direction indicated by the arrow, which is the sheet feeding forward direction.

Roller pair 5.6 of feed roller and separation roller
The feed roller 5 receives power transmission from the first motor M1 via the pulley 12 → the belt 11 → the two-stage pulley 10 → the belt 9 → the pulley 5a, and moves in the clockwise direction A indicated by the arrow in the sheet feeding forward direction. It is driven to rotate.

The separation roller 6 is provided with a second motor M2.
From the pulley 13 → the belt 7 → the pulley 6 a, and is rotated in the clockwise direction B in the direction opposite to the sheet feeding in the nip portion with the feed roller 5.

Roller pair 5.6 of feed roller and separation roller
The feed roller 5 is disposed on a movable chassis 21 that can swing freely about the support shaft of the two-stage pulley 10. 20
Are shafts provided on the upper side of the movable chassis 21;
0a is a cam floor 20 provided at one end of the shaft 20.
a. Reference numeral 19 denotes an eccentric cam, and the movable chassis 21 is biased by a biasing spring member (not shown) around the support shaft of the two-stage pulley 10 so that the cam floor 20a is always in contact with the lower surface of the eccentric cam 19. It is biased to rotate counterclockwise. 27 is an adjustment knob for rotating the eccentric cam 19.

The adjusting knob 27, the eccentric cam 19, the cam floor 20a, the shaft 20, the movable chassis 21 and the like constitute a mechanism for varying the distance between the rollers of the feed roller and the separation roller.

That is, by turning the adjustment knob 27, the cam 19 rotates, and the cam movement is controlled by the cam floor 20a and the shaft 2.
0, which is transmitted to the feed roller 5 via the movable chassis 21 and is displaced in the vertical direction of the feed roller 5, so that the distance between the axes of the feed roller 5 and the separation roller 6 is changed, and
Can be adjusted according to the thickness of the sheet.

When the paper is not fed, the paper feed tray 1 is moved downward to the standby position indicated by the two-dot chain line, and is separated from the paper feed roller 4 downward. The sheets 200 are stacked and set on the sheet feed tray 1 in this state. By inserting the sheet 200 sufficiently until the leading end hits the abutting plate portion 3a, the position of the leading end face of the sheets stacked on the sheet feed tray 1 is aligned.

The paper feed tray 1 based on the paper feed start signal
Is moved upward so that the upper surface on the leading end side of the stacked sheets 200 on the paper feed tray 1 is in contact with the lower surface of the paper feed roller 4 as shown by the solid line.

Then, the uppermost sheet 22 of the stacking sheet 200 is sent out (pickup) by the rotating paper feed roller 4, and is guided by the upper guide plate 2 and the lower guide plate 3, and a nip portion between the feed roller 5 and the separation roller 6. And enters the nip.

The uppermost sheet 22 that has entered the nip portion is
Since the feed roller 5 has a greater frictional force with respect to the sheet than the separation roller 6, the nip is generated by the feed force of the feed roller 5 rotating in the paper feed forward direction regardless of the separation roller 6 rotating in the paper feed reverse direction. Section and is transported.

Further, even if a plurality of sheets 22, 22 ',... Are fed to the nip portion by the sheet feed roller 4 in an overlapped manner, the sheet
Only by the feed force of the feed roller 5 rotating in the feed direction, regardless of the separation roller 6 rotating in the feed reverse direction,
Passing through the nip portion, the other sheets 22 'are returned and conveyed by the separation roller 6 rotating in the reverse direction of the sheet feeding, so that the sheet is prevented from entering or passing through the nip portion and double feeding is prevented. Only one sheet 22 in contact with the roller 5 is separated and conveyed.

Roller pair 5.6 of feed roller and separation roller
The sheet 22 that has been separated and conveyed by the
6. The sheet is sent to a sheet processing unit such as a reading unit (not shown) through the transport roller 17. The registration roller 16 determines a conveyance timing for conveying the sheet 22 to the sheet processing unit in accordance with an instruction from a control unit (CPU) (not shown), and conveys the sheet.

When feeding sheets having different thicknesses,
By rotating the adjustment knob 27, the amount of the feed roller 5 entering the separation roller 6 or the amount of the gap at the nip portion between the pair of the feed roller and the separation roller 5.6 is set to a predetermined sheet thickness. That is, when the rotational position of the cam 19 connected to the adjustment knob 27 changes, the shaft 20 that is in contact with the cam 19 and the shaft 2
0, the movable chassis 21 is moved, and the feed roller 5 changes the center distance with respect to the separation roller 6 to perform the above setting, so that sheets having different thicknesses can be conveyed while avoiding double feed. .

[0025]

In the case of the above-mentioned sheet separating mechanism, the distance between the axes of the feed roller and the pair of comb-like rollers serving as the separating roller is set so that normal separation can be performed even if the thickness of the sheet changes. It is adjustable.

However, the adjustment has to be manually made to an appropriate position for each thickness of the fed sheet, and there is a problem that sheets of different thickness cannot be mixedly loaded.

In order to prevent skew when sheets are separated and conveyed one by one, a movable guide plate (not shown) provided on one side or both sides of the sheet is moved to prevent skew. Correction is made by pressing the side of the seat against the guide plate.

In such a skew feeding correcting mechanism, when conveying sheets having different widths, the position of the guide plate must be changed, which is very troublesome.

The mechanism for detecting the skew of the sheet being conveyed by using the sensor and forcibly correcting the skew by using the conveying rollers as necessary to perform the drive rotation is complicated. There were drawbacks such as wrinkling of the sheet.

Accordingly, an object of the present invention is to provide a sheet feeding apparatus which can automatically separate and convey sheets having different thicknesses with a simple structure and automatically correct skew of the sheets. Is to do.

[0031]

According to the present invention, there is provided a sheet feeding apparatus having the following structure.

(1) A sheet-feeding rotator that rotates in the sheet-feeding forward direction and a sheet-separating rotator that rotates in the sheet-feeding reverse direction at the facing portion are provided between the two rotating members. In a sheet feeding apparatus that separates and conveys sheets by one sheet, at least one of the two rotating bodies changes an inter-axis distance with respect to the other, and an inter-axis distance variable mechanism, and the passage of a sheet provided near the two rotating bodies is performed. And sheet detecting means for detecting. At the start of feeding, at least one of the two rotating bodies starts an operation of separating an axis distance from the other,
. When a sheet is detected by the sheet detecting means,
Stopping the isolation operation of the inter-axis distance; When the sheet feeding is completed, an operation of causing at least one of the two rotating bodies to approach the other to a position at which the center distance becomes impossible with respect to the other is performed for each sheet to be fed. Sheet feeding device.

(2) A sheet-feeding rotator rotating in the sheet-feeding forward direction and a sheet-separating rotator rotating in the sheet-feeding reverse direction at the facing portion are provided between the two rotating members. In a sheet feeding apparatus that separates and conveys sheets by one sheet, at least one of the two rotating bodies changes an inter-axis distance with respect to the other, and an inter-axis distance variable mechanism, and a sheet provided near the two rotating bodies passes through the sheet. And sheet detecting means for detecting. At the start of feeding, at least one of the two rotating bodies starts an operation of separating an axis distance from the other,
. From the time when the sheet is detected by the sheet detecting means, perform an operation of isolating the inter-axis distance by a fixed amount, and then stop the isolating operation of the inter-axis distance; When the sheet feeding is completed, an operation of causing at least one of the two rotating bodies to approach the other to a position at which the center distance becomes impossible with respect to the other is performed for each sheet to be fed. Sheet feeding device.

(3) The sheet-feeding rotary member and the sheet-separating rotary member are rollers, and the rotating shafts of the two rollers are substantially parallel to each other. The sheet feeding device according to (1) or (2), wherein the concave surface and the convex surface have a shape capable of overlapping each other in a non-contact manner in the axial direction.

(4) The sheet feeding rotator and the sheet separating rotator are in a state of preventing sheet feeding before starting sheet feeding or after reducing the distance between the axes (1) to (4). The sheet feeding device according to any one of (3).

(5) A sheet-feeding rotator that rotates in the sheet-feeding forward direction and a sheet-separating rotator that rotates in the sheet-feeding reverse direction at the facing portion are disposed opposite to each other. A sheet feeding device that separates and conveys the sheet by one, wherein an inter-axis distance variable mechanism that changes an inter-axis distance between at least one of the two rotating bodies with respect to the other; And a sheet detecting means provided on the downstream side in the sheet conveying direction of. At the start of feeding, at least one of the two rotating bodies starts an operation of separating the center distance from the other, and. When it is detected by the sheet detection signal on of the sheet detection means that the sheet has passed the closest part of the two rotating bodies, the separation operation of the inter-axis distance is stopped; Performing an operation of, based on a sheet detection signal off of the sheet detecting means, causing at least one of the two rotating bodies to approach the other to a position at which a sheet cannot be fed with respect to the other for each sheet to be fed; A sheet feeding device.

(6) A sheet-feeding rotator rotating in the sheet-feeding forward direction and a sheet-separating rotator rotating in the sheet-feeding reverse direction at the facing portion are provided between the two rotating members. A sheet feeding device that separates and conveys the sheet by one, wherein an inter-axis distance variable mechanism that changes an inter-axis distance between at least one of the two rotating bodies with respect to the other; And a sheet detecting means provided on the downstream side in the sheet conveying direction of. At the start of feeding, at least one of the two rotating bodies starts an operation of separating the center distance from the other, and. When it is detected by the sheet detection signal on of the sheet detection means that the sheet has passed the closest part of the two rotating bodies, from the detection time,
After performing a certain amount of the operation of isolating the inter-axis distance, stopping the operation of isolating the inter-axis distance; Performing an operation of, based on a sheet detection signal off of the sheet detecting means, causing at least one of the two rotating bodies to approach the other to a position at which a sheet cannot be fed with respect to the other for each sheet to be fed; A sheet feeding device.

(7) The sheet-feeding rotary member and the sheet-separating rotary member are rollers, and the rotating shafts of both rollers are substantially parallel, and a comb-shaped groove is formed on the outer periphery. The sheet feeding device according to (5) or (6), wherein the concave surface and the convex surface have a shape capable of overlapping each other in a non-contact manner in the axial direction.

(8) The sheet feeding rotator and the sheet separating rotator are in a state of preventing sheet feeding before starting sheet feeding or after reducing the distance between the axes (5) to (5). The sheet feeding device according to any one of (7).

<Operation> A skew is corrected by abutting a feed sheet against an opposing portion of the sheet feeding rotary member and the sheet separating rotary member, thereby performing an isolation operation for increasing the distance between the two rotary members. To feed the sheet. When it is detected that the fed sheet has passed between the two rotating bodies, the two rotating bodies are in a state in which the sheet cannot be fed because the distance between the shafts is reduced. By performing the above operation for each sheet, the skew correction and the separation of one sheet are performed by the feed roller and the separation roller.

Thus, the sheet feeding apparatus according to the present invention can feed a sheet irrespective of the thickness of the sheet, and can avoid double feeding even if sheets of different thicknesses are mixed. The sheet can be fed to.

Further, skew correction can be performed by abutting the end faces of the skewed and fed sheet against the rotator for sheet feeding and the rotator for sheet separation which overlap each other in the axial direction without contact. It can be carried out.

Accordingly, there is no need to manually adjust the thickness of each sheet, and it is not necessary to detect the posture of the sheet being conveyed and correct skew in the conveyance path.

As described above, since the automatic sheet separation and the skew correction can be performed only by the mechanism of the sheet feeding rotating body and the sheet separating rotating body, the apparatus itself becomes very compact and simple.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment (FIGS. 1 to 5) FIG. 1 is a schematic configuration diagram of a sheet feeding apparatus according to the present embodiment.
Components and parts common to those of the above-described sheet feeding apparatus in FIG. 9 are denoted by common reference numerals, and description thereof will not be repeated.

In the sheet feeding apparatus according to the present embodiment, the nip portion (meshing portion) of the roller pair 5.6 of the feed roller and the separation roller is positioned at the sheet entrance side and the sheet exit side of the nip portion. First and second sheet sensors 14 and 15 as sheet detecting means are provided.

The first sheet sensor 14 includes the sheet feed roller 4
This sensor detects the sheet fed to the nip between the roller pair 5 and 6 of the feed roller and the separation roller, and this sensor is hereinafter referred to as a pre-feed sensor.

The second sheet sensor 15 detects a sheet that has passed through the nip portion between the feed roller and the separation roller pair 5 and 6. This sensor is hereinafter referred to as a post-feed sensor.

Further, in the sheet feeding apparatus of the present embodiment, the rotation of the eccentric cam 19 of the center distance variable mechanism 19, 20a, 20, 21 of the roller pair 5.6 of the feed roller and the separation roller is manually adjusted. Instead of the knob 27, the operation is automatically performed by a stepping motor M3.

That is, the sensor 14 before feeding and the sensor 1 after feeding
5 is a control unit (hereinafter, referred to as CPU) 2
Enter 6 The CPU 26 controls the driving of the stepping motor M3 in accordance with the thickness of the fed sheet based on the detection signal of either the pre-feed sensor 14 or the post-feed sensor 15 to control the pair of feed rollers and separation rollers. By rotating the eccentric cam 19 of the 5.6 inter-axis distance variable mechanism,
By changing the distance between the axes of the feed roller 5 and the separation roller 6, the amount of the feed roller 5 entering the separation roller 6 or the amount of the gap is automatically adjusted appropriately in accordance with the thickness of the sheet.

FIG. 2 is a block diagram of an apparatus control system, and FIG. 3 is an operation flowchart of the apparatus. Signals from the pre-feed sensor 14 and the post-feed sensor 15 are controlled and calculated by the CPU 26, and the first motor M1, the second motor M
2. An operation signal is sent to the stepping motor M3 to drive the mechanism assigned to each.

In the operation flow of FIG.
For loading sheets 200 for paper feed tray 1
And the start of sheet feeding (pickup) by the rotary sheet feeding roller 4 is the same as that of the sheet feeding apparatus of FIG. 9 described above (steps S1 and S2).

The sheet 22 that has reached the nip between the feed roller 5 and the separation roller 6 is detected by the pre-feed sensor 14 (step S3), and overlaps in a non-contact manner in the axial direction to prevent sheet feeding. The roller contacts the engagement portion (nip portion) between the feed roller 5 and the separation roller 6 (step S4).

Here, for example, when the sheets 22 are fed in a state where the sheets 22 are not aligned at the time of stacking and the end surfaces of the stacked sheets 200 are not aligned, or when the sheets 22 are skewed by the sheet feeding roller 4 at the time of feeding. When the sheet is fed or conveyed, the leading end of the fed sheet 22 abuts on the surface where the feed roller 5 and the separation roller 6 mesh with each other, and the sheet 22 is pushed further by the feed roller 4 to be fed, and The end face of the fed sheet 22 is aligned on the surface where the feed roller 5 and the separation roller 6 are engaged, and the posture is corrected.

FIG. 4 shows a state in which the end faces of the sheet 22 are aligned and the posture is corrected. Thereafter, the skew-corrected sheet 22 is conveyed as described below.

When the sheet 22 fed by the feed roller 4 to the nip portion of the pair of feed rollers and separation rollers 5 and 6 is detected by the pre-feed sensor, the CPU 26 changes the center distance variable mechanism M3. The stepping motor M3 of 19 / 20a / 20/21 is driven to control the movement of the feed roller 5 in the direction of separating the feed roller 5 from the separation roller 6, that is, in the upward direction U as shown in FIG. 5 (step S6).

The feed roller 5 and the separation roller 6, each having a comb-shaped groove formed on the outer periphery thereof, face each other, and the concave and convex surfaces of the groove overlap each other in a non-contact manner in the axial direction to prevent the paper feed. It is located in. The feed roller 5 that moves upward expands the interval between the separation roller 6 and the inter-axis direction, and the drive roller of the sheet feed roller 4 and the drive roller of the feed roller 5 mesh with the feed roller 5 and the separation roller 6. The interval is set such that the sheet 22 hitting the sheet can be fed by one sheet.

Here, when the sheets 22, 22 ',... Are fed in a double feed, the uppermost sheet 22 which is in direct contact with the feed roller 5 is fed by the feed roller 5 which rotates in the feed direction. Fed, and the other multi-feed sheets 22 'are conveyed back by the separation roller 6 rotating in the reverse direction of the paper feeding, and are prevented from entering or passing through the nip portion, thereby preventing double feed. Only one sheet 22 in contact with the roller 5 is separated and conveyed.

When the uppermost sheet 22 has passed the space between the feed roller 5 and the separation roller 6, the post-feed sensor 15 detects the passage of the sheet 22 (step S7), and
The detection signal is transmitted to U26.

Upon receiving the detection signal, the CPU 26 feeds back the signal to the stepping motor M3 to stop driving the stepping motor M3. At this time, the feed roller 5 is positioned between the separation roller 6 and the sheet 22.
In addition to the interval corresponding to the thickness of one sheet, the load is not applied to the sheet 22 in feeding the sheet, and the sheet is fed by the feed roller 5.
A certain extra value is provided so that the sheet can pass smoothly between the roller and the separation roller 6 (step S8).

Stepping motor M3 stopped driving
Is stopped (step S9), the operation of the inter-axis distance variable mechanism between the feed roller 5 and the separation roller 6 stops (step S1).
0).

Sheet 22 detected by sensor 15 after sheet feeding
The registration roller 16 is determined based on the conveyance speed of the sheet 22 and the distance between the sensor 15 and the registration roller 16 after the sheet is fed, based on the time until the sheet 22 reaches the registration roller 16 or a preset number of motor pulses. CPU equipped with arithmetic means for detecting timing sent to
6, when it is detected that the sheet reaches the registration roller 16 and is conveyed, the driving rotation of the sheet feeding roller 4 and the feed roller 5 is stopped in order to avoid the next sheet 22 '... (Step S13).

The transport timing of the fed sheet 22 is determined by the registration rollers 16 and then transported to the transport rollers 17.

Since the sheet 22 is conveyed by the registration roller 16, the driving of the sheet feeding roller 4 and the feed roller 5 is released, and the sheet roller 4 and the feed roller 5 are rotated (step S14).

Thereafter, when the post-feed sensor 15 detects that one of the fed sheets 22 has passed between the feed roller 5 and the separation roller 6 (step S16), the inter-axis distance is changed. The driving of the stepping motor M3 of the mechanism is restarted. The driving of the stepping motor M3 at this time is in the direction of moving the feed roller 5 in the downward direction D as shown in FIG. 5 (step S17).

As a result, the feed roller 5 and the separation roller 6 approach each other in a non-contact manner in the axial direction, and return to the state before the feed, which overlaps and prevents the sheet feeding (step S18).

Next, based on the fact that the driving of the stepping motor M3 is stopped and the operation of the inter-axis distance variable mechanism is stopped, the operation in which the feed roller 5 and the separation roller 6 approach each other in a non-contact manner in the axial direction also stops. , The state before the feeding (step S20).

At this time, even if sheets of different thicknesses are mixed and fed, the feed roller 5 and the separation roller 6 are movable as described above, and the sheet detection sensor detects the passage of each sheet 22 and detects the passage. Therefore, the sheet can be automatically separated and fed regardless of the thickness of the sheet 22.

Next, when the pre-feed sensor 14 detects that the second sheet 22 'has been fed (step S21), the feed roller 4 and the feed roller 5 start driving and rotating (step S21). Step S22), the feeding of the second sheet 22 'is started (steps S1 and S3).

The above series of operations is performed for each sheet 22 to be fed.

<Second Embodiment> (FIGS. 6 and 7) FIG. 6 is a schematic configuration diagram of a sheet feeding apparatus according to a second embodiment.

The difference from the apparatus of the first embodiment is that the paper is fed by the paper feed roller 4 in the first embodiment, whereas in the present embodiment, the paper is fed in the directions of arrows EF. The surface direction of the sheet 200 is supported by the slidable sheet guide 29 and the upper guide plate 2, and the sheet feed side end surface is supported by the sheet leading end abutting plate portion 3 a which is an extension of the lower guide plate 3. The slide-type seat guide 29
That is, the paper is fed.

Further, since the sheet 200 abuts on the feed roller 5 and the separation roller 6 from the beginning, the need for the sensor 14 before feeding is eliminated, and the same operation as in the first embodiment can be performed only by the sensor 15 after feeding. It becomes possible.

The operation of the present embodiment will be described. The sheet 200 set at a fixed position at the time of feeding a sheet is fed to the sheet feeding section (nip) where the feed roller 5 and the separation roller 6 are overlapped by the sliding sheet guide 29. ), The sheet is fed in the direction of arrow E while the end face is abutted against the sheet leading end abutting plate 3a.

In the vicinity of the sheet feeding section, the sheet 200 slides under its own weight to the sheet feeding section along the tapered sheet front end abutting plate section 3a.
The skew is corrected by colliding with the overlapping portion. At this time, the slide type sheet guide 29 holds the posture of the sheet 200 by the upper guide plate 2, and the feed roller 5 and the separation roller 6 with which the sheet 200 abuts are in a state where their drive rotations are stopped.

Next, after a sufficient time has passed since the sheet 200 is set at a predetermined position and the slide type sheet guide 29 is moved, the feed roller 5 and the separation roller 6 start to rotate.

Thereafter, the feed roller 5 moves from the separation roller 6 in a direction that separates the distance between the axes.

After the sheet 200 is fed by the above operation, the same operation as in the first embodiment is performed.

FIG. 7 shows a flowchart of the above operation.

<Third Embodiment> (FIG. 8) FIG. 8 is a schematic configuration diagram of a sheet feeding apparatus according to a third embodiment.

The difference from the apparatus of the first embodiment is that the feed roller 5 can be moved in the vertical direction in the first embodiment, whereas the separation roller 6 is moved in the vertical direction in the present embodiment. , And the feed roller 5 is at a fixed position.

The separation roller 6 is held by a movable chassis 23 which can rotate coaxially with a support shaft 24 of a pulley 13 which is driven to rotate by a second motor M2 (not shown). The separation roller 6 is rotated by receiving a driving force via the pulley 13 → the belt 7 → the pulley 6a.

A gear 25 is provided integrally with the movable chassis 23 and is coaxial with the shaft 24. 26 is a worm gear meshed with the gear 25. The rotation of the worm gear is controlled by a stepping motor M3.

When the stepping motor M 3 is rotated forward and backward, the worm gear 26 rotates the gear 25, that is, the movable chassis 23 in the clockwise direction C or the counterclockwise direction D about the shaft 24.

When the movable chassis 23 is rotated in the clockwise direction C, the separation roller 6 is moved in a direction of separating the distance from the feed roller 5, that is, downward.

When the sensor 15 detects that one sheet 22 has passed between the separated feed roller 5 and the separation roller 6 after feeding, the movable chassis 23 is rotated in the counterclockwise direction D. As a result, the separation roller 6 is
, And moves upward in a direction in which they overlap each other in a non-contact manner, and stops moving in the vertical direction at a position before sheet feeding. During this time, the separation roller 6 is pulled from the pulley 13 → the belt 7 →
It rotates by receiving a driving force via the pulley 6a.

These operations are performed for each sheet fed in the same manner as in the first embodiment.

<Others> 1) The feed roller and the separation roller need not be comb-shaped rollers. One or both of them may be a rotating belt.

2) The mechanism for varying the distance between the shafts of the feed roller and the separation roller may be configured to move both the feed roller and the separation roller in directions of increasing and decreasing the distance between the shafts.

3) The present invention is not limited to the apparatus of the upper separation feeding system for feeding from the upper sheet of the stacked sheets, but also the apparatus of the lower separation feeding system for feeding from the lower sheet of the stacked sheets. Applicable.

4) The sheet feeding apparatus of the present invention includes a rotary type camera, a facsimile apparatus, a printing machine, a copying machine, a printer,
In image forming devices such as word processors, and various sheet-using devices such as automatic document feeders, punches, paper binding machines, etc., stacked sheets such as cards and thin paper are processed into image forming units, exposure units, processing units, etc. It can be widely used as an apparatus that feeds and conveys one sheet to a sheet processing unit.

[0092]

As described above, according to the present invention, with a simple structure, sheets having different thicknesses can be automatically separated and conveyed, and skew of the sheets can be automatically corrected. A sheet feeding device can be provided.

That is, the sheet feeding apparatus according to the present invention can feed sheets irrespective of the thickness of the sheets, and can avoid double feeding even if sheets of different thicknesses are mixed. The sheet can be fed to.

The skew correction is performed by abutting the end faces of the skewed and fed sheet against the sheet feeding rotator and the sheet separating rotator that are overlapped in the axial direction without contact with each other. It can be carried out.

Thus, there is no need to manually adjust the thickness of each sheet, and it is not necessary to detect the posture of the sheet being conveyed and correct skew in the conveyance path.

Since the automatic sheet separation and the skew correction can be performed only by the mechanism of the sheet feeding rotating body and the sheet separating rotating body, the apparatus itself becomes very compact and simple.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram of a sheet feeding apparatus according to a first embodiment.

FIG. 2 is a block diagram of a control system.

FIG. 3 is an operation flowchart.

FIG. 4 is a perspective view showing a state in which a skewed sheet is hit against a feed roller and a separation roller to perform skew correction.

FIG. 5 is a perspective view showing vertical movement of a feed roller.

FIG. 6 is a schematic configuration diagram of a sheet feeding apparatus according to a second embodiment.

FIG. 7 is an operation flowchart.

FIG. 8 is a schematic configuration diagram of a sheet feeding apparatus according to a third embodiment.

FIG. 9 is a schematic configuration diagram of a conventional sheet feeding apparatus.

[Explanation of symbols]

 5: feed roller 6: separation roller 14: sensor before sheet feed 15: sensor after sheet feed 22: sheet 26: CPU

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Kazuhide Sugiyama 1248 Shimokagemori, Chichibu City, Saitama Prefecture Inside Canon Electronics Co., Ltd.

Claims (8)

[Claims] 1. A sheet feeding rotating body that rotates in a sheet feeding forward direction at an opposed portion and a sheet separating rotating body that rotates in a sheet feeding reverse direction at an opposed portion. In a sheet feeding apparatus that separates and conveys a sheet, at least one of the two rotating bodies changes an axial distance with respect to the other, and an inter-axis distance variable mechanism detects passage of a sheet provided near the two rotating bodies. And sheet detecting means. At the start of feeding, at least one of the two rotating bodies starts an operation of separating the center distance from the other, and. When a sheet is detected by the sheet detecting means, the separating operation of the center distance is stopped,
. When the sheet feeding is completed, an operation of causing at least one of the two rotators to approach the other to a position where the axis cannot be fed with respect to the other is performed for each sheet to be fed. Sheet feeding device. 2. A sheet feeding rotating body which is arranged to face and rotates in a sheet feeding forward direction at an opposing portion, and a sheet separating rotating body which rotates in a sheet feeding reverse direction. In a sheet feeding apparatus that separates and conveys a sheet, at least one of the two rotating bodies changes an axial distance with respect to the other, and an inter-axis distance variable mechanism detects passage of a sheet provided near the two rotating bodies. And sheet detecting means. At the start of feeding, at least one of the two rotating bodies starts an operation of separating the center distance from the other, and. From the time when the sheet is detected by the sheet detecting means, perform an operation of isolating the inter-axis distance by a fixed amount, and then stop the isolating operation of the inter-axis distance;
When the sheet feeding is completed, an operation of causing at least one of the two rotating bodies to approach the other to a position at which the center distance becomes impossible with respect to the other is performed for each sheet to be fed. Sheet feeding device. 3. The sheet-feeding rotary member and the sheet-separating rotary member are rollers, and the rotating shafts of the two rollers are substantially parallel to each other. The sheet feeding device according to claim 1, wherein the concave surface and the convex surface have a shape capable of overlapping each other in an axial direction without contact. 4. The sheet feeding rotator and the sheet separating rotator are in a state of hindering sheet feeding before starting sheet feeding or after approaching the center distance. The sheet feeding device according to any one of the above. 5. A rotating body for feeding a sheet, which is disposed to face and rotates in a forward direction in a sheet feeding direction at a facing portion, and a rotating body for separating a sheet, rotating in a reverse direction to feed a sheet. In a sheet feeding device that separates and conveys a sheet, at least one of the two rotating bodies changes an axial distance with respect to the other, and an inter-axis distance variable mechanism; A sheet detecting means provided on the downstream side in the sheet conveying direction;
At the start of feeding, at least one of the two rotating bodies starts an operation of separating the center distance from the other, and. When it is detected by the sheet detection signal on of the sheet detection means that the sheet has passed the closest part of the two rotating bodies, the separating operation of the inter-axis distance is stopped. Performing an operation of, based on a sheet detection signal off of the sheet detection means, causing at least one of the two rotating bodies to approach the other to a position at which the inter-axis distance cannot be fed for each sheet to be fed; A sheet feeding device. 6. A sheet feeding rotator rotating in a sheet feeding forward direction at an opposing portion and a sheet separating rotator rotating in a sheet feeding reverse direction at an opposing portion. In a sheet feeding device that separates and conveys a sheet, at least one of the two rotating bodies changes an axial distance with respect to the other, and an inter-axis distance variable mechanism; A sheet detecting means provided on the downstream side in the sheet conveying direction;
At the start of feeding, at least one of the two rotating bodies starts an operation of separating the center distance from the other, and. When it is detected by the sheet detection signal on of the sheet detection means that the sheet has passed the closest part of the two rotating bodies, from the time of the detection, after performing an operation of isolating the inter-axis distance by a fixed amount, Stop the isolation operation of the distance between axes,. Performing an operation of, based on a sheet detection signal off of the sheet detecting means, causing at least one of the two rotating bodies to approach the other to a position at which a sheet cannot be fed with respect to the other for each sheet to be fed; A sheet feeding device. 7. The sheet-feeding rotary member and the sheet-separating rotary member are rollers, and the rotating shafts of the two rollers are substantially parallel to each other. The sheet feeding device according to claim 5, wherein the concave surface and the convex surface have a shape capable of overlapping each other in a non-contact manner in the axial direction. 8. The sheet feeding rotator and the sheet separating rotator are in a state of preventing sheet feeding before starting sheet feeding or after approaching the center distance. The sheet feeding device according to any one of the above.