JPH09216739A - Sheet feeder and image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the slant moving of a sheet by the effect of the phase shift of a notch surface and the curl of the sheet, in a device for feeding the sheet by a feed roller having a partial notch part. SOLUTION: In the stop position of a solid line of a feed roller 1 having a circumferential part and partial notch, a sheet is inserted from an insertion port 5 formed by guides 3, 4 to a shutter 12 and a feed roller 1 is turned upto a chain line position and a presser roller 8 is moved to the feed roller 1 side and the sheet is held by both and thereafter, the shutter 12 is released and the sheet is sent toward a resist roller by the feed roller.

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 copying machine, an LBP, and a word processor, and an automatic document feeder attached to the image forming apparatus, and a sheet feeding device in an apparatus using a sheet material such as an automatic document reading device.

[0002]

2. Description of the Related Art Conventionally, in an image forming or image reading apparatus such as a copying machine or a printer, a conveying speed of a pair of conveying rollers (hereinafter referred to as registration rollers) for conveying a sheet in the vicinity of the image forming section or the image reading section. For various reasons such as the stabilization of the registration roller, prevention of skew, improvement of durability, etc., as shown in FIG. 9, by using the feeding roller 106 having a substantially half-moon cross-sectional shape on the upstream side of the registration roller pair 109, the registration roller pair 109 is used. The transport by 109 is not obstructed.

In the drawing, reference numeral 101 is a sheet material cassette as a sheet material stacking and storing section. Reference numeral 102 denotes an intermediate plate arranged in the cassette 101 by being pushed up by a spring member 103 and S is loaded on the intermediate plate 102 and S is loaded on the cassette 101.
The sheet material 104 accommodated in the inside is a separation claw as a sheet material separation member engaged with the left and right corners of the top surface of the stacked sheet material on the leading edge side (the leading edge side in the sheet material feeding direction). The cassette 101 can be freely attached / detached by inserting / removing it into / from a cassette receiver 105 of the copying machine such as a copying machine.

Reference numeral 106 denotes a sheet feeding roller or a pickup roller as a sheet material feeding rotating body on the side of the copying machine such as a copying machine, and the roller has a half-moon shape in which a part of the circumferential surface 106a is a flat cut surface 106b. It is a roller made of friction material such as rubber. Reference numeral 107 denotes a rotation center shaft of the roller, and the roller 106 is integral with the shaft 107. This shaft 107 is driven by one rotation (360 ° rotation) clockwise in the drawing for each sheet material feeding start signal by a drive mechanism (not shown). That is, the roller 106 is driven to rotate once. In the feeding roller 106, the cut plane portion 106b is always facing downward in FIG. 9 (a).
The rotation angle state indicated by the solid line is set as the standby rotation angle position, and the rotation is stopped. Cassette 101 is cassette receiver 1
In the state in which it is inserted into the main body 05 such that it is inserted into the copying machine such as a copying machine, the leading end side of the upper surface of the stacking and storing sheet material S in the cassette 101 is the feeding roller 106 in the standby rotation angle position state. Downward cut plane portion 106b
Faces in a non-contact manner with a gap α below.

The cassette 101 with respect to the cassette receiver 105
When inserting / removing, the cut plane portion 106 of the roller 106
Since b is downward, the roller 106 does not contact and interfere with the stacked storage sheet material S of the cassette 101 to be inserted / removed, and the cassette 101 can be attached / detached without being disturbed.

(A) When one rotation drive of the feeding roller 106 is started based on the sheet material feeding start signal from the standby state of FIG. 9A, the starting end portion 10 of the roller circumferential portion 106a is started.
6c (the joining portion of the cut flat surface portion 106b and the circumferential surface portion 106a on the downstream side in the roller rotation direction) contacts the upper surface of the uppermost sheet material S1 of the stacked sheet material S as shown by the two-dot chain line in FIG. 9 (a). To do. Then, by the subsequent rotation of the roller 106, the roller circumferential surface 106a contacts the upper surface of the uppermost sheet material S1 of the stacked sheet S while pushing down the stacked sheet material S / middle plate 102 against the pushing force of the spring member 103. .
As a result, due to the frictional force between the circumferential surface 106a of the roller 106 and the uppermost sheet material S1 due to the reaction force of the spring member 103 and the subsequent rotation of the roller 106, the uppermost sheet material S1 is fed in the feeding direction. Will be sent.

(B) The feeding force is the uppermost sheet material S1
The left and right corners on the leading edge side of the separating claw 104 are pushed out from the lower surface side to the upper surface side of the separation claw 104, and only the uppermost sheet material S1 is removed from the stacking sheet material of the second or lower order. As shown in 9 (b), one sheet is separated.

(C) The uppermost sheet material S1 separated by one sheet is passed through the guide plates 108a and 108b by the conveying force due to the subsequent rotation of the roller 106, and the registration roller pair 109 is formed.
It is sent to the nip part of a 109b. The pair of registration rollers 109a and 109b are held in a rotation stopped state,
The leading edge of the above-mentioned feeding sheet material S1 abuts against the nip portion and is received. Registration roller pair 109a ・ 10
9b is held in a rotation stopped state for a while after the leading edge of the sheet material S1 reaches and abuts against the nip portion, and during that time, the feeding roller 106 continues to feed the sheet material S1. To do. As a result, a flexible loop portion is formed in the sheet material portion between the feeding roller 106 and the nip portion of the pair of registration rollers 109a and 109b as shown in FIG. 9C. The elastic force of the flexible loop causes the leading edge of the sheet material S1 to abut against the entire length of the sheet material in parallel along the length of the nip portion of the registration roller pair 109a and 109b, whereby the sheet material S1 is obliquely removed. It

(D) A predetermined timing a little before the end of the end portion 106d of the circumferential portion 106a passing the upper surface of the uppermost sheet material S1 and becoming non-contact near the end of one rotation of the feeding roller 106. Registration roller pair 10
The rotation drive of 9a and 109b is started. As a result, the sheet material S1 starts to rotate.
a. 109b, the sheets are synchronously fed at a predetermined conveying speed to a sheet material receiving portion such as an image forming portion (not shown) of the copying machine. The feeding roller 106 then completes one rotation drive, reaches the first standby rotation angle position where the cut flat surface portion 106b faces downward, is held in a rotation stopped state, and is in a non-contact state with the uppermost sheet material S1. The edges are cut off. However, the uppermost sheet material S1 is fed by the registration roller pair 109a.
・ Continued with rotation of 109b. In this process, since the feeding roller 106 is not in contact with the sheet material S1 as described above, there is no back tension due to the roller 106 coming into contact with the sheet material S1 fed by the registration roller pair 109a and 109b. As a result, the sheet material S1 is transferred to the registration roller pair 109 at a stable predetermined speed.
It is fed by a.109b.

(E) Registration roller pairs 109a and 109
After the trailing edge of the sheet material S1 has passed through the nip portion, the rotation of the sheet b is stopped and stands by until the feeding of the next sheet material is started.

(F) Thus, each time the feeding roller 106 is driven to rotate by the sheet material feeding start signal, the above (a) to
The operation cycle of (e) is repeatedly executed and the cassette 1
The stacked storage sheet materials S in 01 are separated and fed one by one from the topmost sheet material.

In the sheet material feeding device of this type, a plurality of feeding rollers 106 are used in the longitudinal direction of the shaft 107 in order to stabilize the sheet feeding by the feeding rollers 106.

[0013]

However, in the above-mentioned conventional example, when a plurality of feeding rollers 106 arranged out of phase with each other, the feeding rollers 106 rotate to first contact the feeding rollers 106c. Since the sheet feeding is started from the contacted portion, the sheet feeding becomes unstable such as skew of the sheet. Also,
Even if the feeding rollers 106 are attached to the shaft 107 with high accuracy, it is inevitable that the abutment timing of the sheet C and the 106c portion of each feeding roller 106 is deviated due to curling or waviness of the sheet S. This has been a factor of deteriorating the conveyance stability by the feeding roller 106.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and a first invention of the present application is a feed rotary member having a partial cutout, and the feed rotary member. It is characterized by comprising a rotation control means for stopping at least two positions and a pressure member capable of coming into contact with and separating from the feeding roller.

According to a second aspect of the present application, a registration means for correcting skew of the sheet is provided upstream of the image input / output unit in the sheet conveying direction, and the sheet is provided upstream of the registration means in the sheet conveying direction. It is characterized by comprising a feeding device.

A third invention according to the present application is provided with the sheet feeding device, and an image forming means for inputting or outputting an image of the sheet conveyed by the sheet feeding device.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A schematic configuration of an image reading apparatus equipped with a sheet conveying apparatus according to the present invention will be described with reference to FIGS.

In the figure, the paper feed roller 1 has a circumferential surface 1a and a flat cut surface 1b or a partial cutout such as a substantially half-moon cross-section having a cutout, and is rotatable about an axis 2. Further, the paper feed roller 1 includes a stepping motor (not shown), a spring clutch having two control cores, and the like, and a first stop position (shown by a solid line in FIG. 1) and a second stop position (shown by a broken line in FIG. 1). It is configured so that it can be stopped / rotated at a single position. The pressure roller 8 is arranged at a position facing each of the paper feed rollers 1 and the arm 7 is provided.
Is rotatably supported. Also, this arm 7
The shaft 10 is swingably supported about a shaft 10 and is separated from the sheet feeding roller 1 by an actuator such as a solenoid 6 (solid line in FIG. 1) and a pressing position abutting the sheet feeding roller 1 (broken line in FIG. 1). It is possible to switch between two positions (shown by).

Further, the shutter 12 is for controlling the insertion amount when a user inserts a sheet original (hereinafter referred to as "sheet") from the insertion opening 5 formed by the guides 3, 4. An actuator such as the solenoid 11 can open / close the sheet conveyance path 19 formed from the conveyance guides 3 and 4.

A sheet detection sensor 13 including a photo sensor is provided between the shutter 12 and the paper feed roller 1 to detect the insertion of the sheet by the user.

Numerals 15a and 15b are a pair of active registration rollers as registration means, which are arranged in front in the longitudinal direction.
Two units are provided in the back and each has an independent driving unit. Then, the skew of the sheet S is corrected by changing the transport speed of the active registration rollers 15 that are independently driven in the front and back.

Reference numeral 16 is a skew amount detection sensor as a sheet skew amount detecting means, and two skew amount detection sensors are arranged in a direction orthogonal to the sheet conveying direction, and based on a signal that the leading edge of the sheet crosses each sensor. The inclination of the leading edge of the sheet is detected. As the skew detection sensor 16, for example, a transmissive photo sensor is used, and the sheet S blocks the optical path of the photo sensor to detect the passage of the leading end thereof. The sheet S is conveyed while being conveyed to the reading unit 17 by controlling the conveyance speed of the rollers in the front and back of the active registration roller pair 15 based on the signal of the skew detection sensor 16.
Skew is corrected.

Then, the sheet is conveyed by a pair of conveying rollers 18 provided on the further downstream side, and is discharged to a discharging portion (not shown).

In the reading unit 17, the reflected light obtained by irradiating the sheet S conveyed on the platen glass with light is imaged on a photoelectric conversion element such as a CCD through a short-focus imaging lens or the like. The image information is electrically encoded and stored in the memory.

In order for the skew feed correction by the pair of active registration rollers 15 to work effectively, it is necessary to hold the sheet S only by the pair of active registration rollers 15 during skew feed correction. For this reason, the arrangement of the rollers 15, 1, the sensors 13, 16 and the shutter 12 is arranged and the sheet feeding roller 1 is arranged so that the sheet conveyance by the sheet feeding roller 1 ends between the pair of active registration rollers 15 and the skew detection sensor 13. Shape 1 is selected.

Next, the operation of the sheet feeding apparatus according to the present invention will be described with reference to the flow chart shown in FIG. 7 and FIGS.

The user inserts the sheet S from the manual insertion slot 5 until the leading edge of the sheet S contacts the shutter 12 (step).
1) When the sheet detection sensor 13 detects the above (step 2), the feeding roller 1 is rotated to the second stop position and stopped by the driving means (not shown) based on the detection signal. It faces the pressure roller 8 (steps 3, 4, 5 and FIG. 2).

At this time, the pressure roller 8 is connected to the solenoid 6
By this action, since the separated state is maintained in which the sheet is separated from the feeding roller 1, the sheet is not given a conveying force by the rotation of the feeding roller 1 from the first stop position to the second stop position. At the next predetermined timing, a predetermined signal is given to the solenoid 6 and the solenoid 11 so that the pressure roller 8 is pressed and the shutter 12 is released (step
(p6, 7 and FIG. 3), the conveyance path 19 from the feeding roller 1 to the active registration roller pair 15 is released. Then, the sheet feeding roller 1 is rotated until the feeding roller 1 is located at the first stop position, and stopped at the first stop position (step 8,
9, 10 and FIG. 4). The sheet is conveyed by the active roller 15 and the conveying roller 18, and after a lapse of a predetermined time (after the rear end of the sheet passes through the shutter portion) after detecting that the rear end of the sheet S has passed through the sheet detection sensor, the solenoid. A predetermined signal is input to the solenoid 11 and the solenoid 6, the shutter 12 is returned to the state in which the conveyance path 19 is closed, and the pressure roller 8 is separated from the sheet feeding roller 1 to return to the initial state, and the next feeding is performed. The process is completed in preparation for the paper operation (steps 11, 12, 13 and the state of FIG. 5).

In this way, the sheet S is fed by the feeding roller 1
As described above, the sheet is passed from the active registration roller pair 15 to the active registration roller pair 15 by the feeding roller 1 when the leading edge of the sheet is conveyed to the position A between the active registration roller 15 and the skew detection sensor 16. Since the sheet is returned to the stop position, the sheet is always held only by the pair of active registration rollers when the leading edge of the sheet reaches the skew detection sensor 16 and the skew amount is detected and skew correction is performed by the active registration roller 15. Therefore, it is possible to maintain the skew correction accuracy with high accuracy.

In the above embodiment, solenoids are independently provided as position switching means for the shutter 12 and the pressure roller 8, but as shown in FIG.
Also, the pressure roller 8 may be operated in conjunction with each other.

In addition, as shown in FIG.
It may be applied to a feeding cassette unit that separates and feeds the sheets one by one. Further, although the present embodiment has been described using the document reading device as the image input unit, it is needless to say that the same effect can be obtained by using the image reading unit such as the transfer unit of the copying machine.

[0032]

As described above, according to the present invention, a feeding rotary member having a circumferential portion and a partial cutout for feeding a sheet,
The sheet is provided with a rotation control means for stopping the feeding rotating body at at least two stop positions, and a pressure member capable of coming into contact with and separating from the feeding roller, so that the sheet has a notch. It is possible to reliably hold the sheet between the circumferential portion of the body and the pressure member before starting the conveyance. As a result, there is no phase misalignment of the cutout surface of each feeding rotating body, and there is no conveyance failure such as skewing due to the contact timing deviation between the sheet and the feeding rotating body due to floating or curling of the sheet. It has become possible to provide a stable sheet feeding device.

[Brief description of drawings]

FIG. 1 is a sectional view of an original reading apparatus according to an embodiment of the present invention in an operating state.

FIG. 2 is a sectional view of an original reading device according to an embodiment of the present invention in an operating state.

FIG. 3 is a sectional view of an original reading apparatus according to an embodiment of the present invention in an operating state.

FIG. 4 is a sectional view of an original reading apparatus according to an embodiment of the present invention in an operating state.

FIG. 5 is a sectional view of an original reading device according to an embodiment of the present invention in an operating state.

FIG. 6 is a sectional view of a document reading device according to another embodiment of the invention.

FIG. 7 is a flowchart showing the operation of the embodiment according to the present invention.

FIG. 8 is a diagram showing a sheet feeding device according to another embodiment of the invention.

FIG. 9 is a diagram showing a conventional sheet feeding device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Feed roller 8 ... Pressure roller 12 ... Shutter 13 ... Sheet detection sensor 15 ... Active registration roller pair 16 ... Skew amount detection sensor 17 ... Image reading unit 18 ... Conveying roller

Claims (4)

[Claims] 1. A feeding rotating body for feeding a sheet, which has a circumferential portion and a partial notch, rotation control means for stopping the feeding rotating body at at least two stop positions, and the feeding roller. A sheet feeding device including a pressing member that can be brought into and out of contact with the sheet feeding device. 2. A registration means for correcting skew of the sheet is provided upstream of the image input / output unit in the sheet carrying direction, and the sheet feeding device according to claim 1 is provided upstream of the registration means in the sheet carrying direction. Sheet feeding device. 3. The seat according to claim 2, wherein the two stop positions are set at a position where a part of the notch faces the seat and a position where the vicinity of the starting end of the circumferential part faces the pressing member. Feeder. 4. An image forming apparatus comprising: the sheet feeding device according to claim 1; and an image forming unit that inputs or outputs an image of a sheet conveyed by the sheet feeding device.