JP3875003B2 - Paper transport device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a paper transporting device that can be mounted on an image reading device or an image forming device such as a copying machine, a facsimile device, a scanner device, or a printer device.In placeSpecifically, the paper transport apparatus is configured to correct the skew of the paper by abutting the front end of the paper against the nip portion of the rotating member.In placeRelated.
[0002]
[Prior art]
An image forming apparatus or an image reading apparatus such as a copying machine, a facsimile apparatus, a scanner apparatus, or a printer apparatus is equipped with various types of automatic document conveying apparatuses for conveying a read document. After feeding a bundle of documents placed on a document table by a pickup roller, the bundle is separated one by one by a feed belt and a reverse roller provided on the downstream side of the document table in the document conveyance direction and conveyed to a reading position. I am doing so.
[0003]
As this image reading method, there is a method in which an original separated into one sheet is stopped on a contact glass, and an optical system is scanned on the original surface. In this method, a scanner carriage that moves the optical system moves to a reading start position. In order to discharge the original on the contact glass according to the page order, the loss of the time to return to the page occurs, and the CPM (number of copies to be discharged per minute) is lower than when only the copy function is used. In this case, the document must be discharged to an external discharge tray provided on the outside of the main body, which causes a problem that space cannot be reduced.
[0004]
As an automatic document feeder for solving such a problem of the image reading method, there is a so-called sheet-through method in which a scanner carriage is fixed and an original is moved on an optical system fixed by the scanner carriage. It is used frequently and is now becoming mainstream.
[0005]
According to this sheet-through method, by controlling the interval between the read originals, a CPM equivalent to the copy function can be secured if the original interval is reduced to the maximum, and the discharged original is provided below the original table. The sheet can be discharged to the discharged sheet discharge table, and an external tray can be made unnecessary.
[0006]
However, in such a configuration, the skew of the document occurs due to various transport members that transport the document to the reading position, for example, the roller pressure balance of the pair of transport rollers, and the document is read. The skew must be corrected inside the machine before the position is reached.
[0007]
Therefore, a pair of document conveying rollers provided in the apparatus (hereinafter, this roller pair is referred to as a butting roller pair) has a skew correction function, and the leading edge of the document is placed at the nip portion of the butting roller pair that has stopped rotating. By abutting and bending the document to form a loop, the leading edge of the document is aligned and the skew of the document is corrected.
[0008]
However, when correcting the skew of the document in this way, when transporting the document with the abutting finished and the loop formed, only the butting roller pair is driven to pull the document. However, it is possible to eliminate the bending of the paper, but ideally, the leading edge is stopped without being reliably guided to the nip part of the abutting roller pair, such as a thick paper document, etc. If the leading edge is aligned but the leading edge of the document is not sandwiched between the abutting roller pair, a non-feed jam occurs when the abutting roller pair is driven.
[0009]
As a means for solving such a problem, for example, there is a technique described in JP-A-6-336353. In this case, the registration roller pair is stopped for a predetermined time until the leading edge of the document fed by the feeding means abuts against the nip of the registration roller pair to cause bending, and then the document is moved over the entire nip of the registration roller pair. The registration roller is driven at a low speed until it is sandwiched between the two, and then stopped at a low speed, and then the feeding unit and the registration roller pair are driven at a predetermined timing to convey the document.
[0010]
On the other hand, in such a sheet-through type automatic document feeder, a pickup roller and a paper feed belt are provided in order to reduce the manufacturing cost by simplifying the configuration of the device and reducing the number of parts. Some reverse rollers and registration rollers are driven by the same driving means, for example, a stepping motor. This is provided with a clutch means for stopping the rotation of the registration roller for skew correction. The registration roller is turned on / off so as not to affect the operation of the common stepping motor. It can be driven independently of the pickup roller.
[0011]
[Problems to be solved by the invention]
However, in the apparatus having the skew correction function described in the conventional example, the registration roller pair is stopped for a predetermined time until the leading edge of the document abuts against the nip of the registration roller pair to cause bending. Thereafter, the registration roller is stopped after being driven at a low speed until the document is nipped across the nip of the registration roller pair, and then the feeding unit and the registration roller pair are driven at a predetermined timing. And the driving means for driving the registration roller pair must be provided separately, and the manufacturing cost cannot be reduced sufficiently by simplifying the configuration of the automatic document feeder and reducing the number of parts. was there.
[0012]
  Therefore, the present invention achieves the simplification of the configuration and the reduction in the number of parts to reduce the manufacturing cost, and corrects the skew of the paper to reliably convey the corrected paper, High-quality paper transport device that can prevent paper non-feed jamsPlaceIt is intended to provide.
[0017]
[Means for Solving the Problems]
  BookIn order to solve the above problems, the invention provides a separation sheet feeding unit that separates and feeds sheets one by one from a sheet bundle placed on a sheet placing table, and a downstream side of the separation sheet feeding unit in the sheet conveying direction. A pair of rotating members that sandwich and convey the separated paper, a single driving unit that drives the rotating member and the separation sheet feeding unit, and a clutch unit that rotates and fixes the rotating member, Control means for driving the driving means and switching the rotation member to a fixed state or a rotating state by operating the clutch means, and fixing the leading edge of the paper separated by the separation paper feeding means In the sheet conveying apparatus in which the sheet is bent by abutting against the nip portion of the rotating member in a state to correct the skew of the sheet, the control unit includes the rotating unit. The driving means is stopped after a lapse of a certain period of time after the leading edge of the paper comes into contact with the nip portion of the paper, and the driving means is driven for a predetermined time and stopped after the clutch means is switched from the fixed state to the rotating state Then, control is performed so as to drive the driving means after a predetermined time.
[0018]
In that case, the rotating member and the separation sheet feeding unit are driven by a single driving unit, and the rotation member is driven by the clutch unit, whereby the rotating member can be driven independently of the separation sheet feeding unit. Simplification of the configuration of the conveying device and reduction in the number of parts can be achieved, thereby reducing the manufacturing cost.
[0019]
In addition, by stopping the drive means after a certain period of time has elapsed since the leading edge of the paper comes into contact with the nip portion of the rotating member, the rotating member deflects the paper to correct the skew of the paper, and the clutch means is fixed. By switching from the rotating state to the rotating state, the rotating member is driven and stopped for a certain period of time, so that the leading edge of the sheet is sandwiched in the entire nip portion using the bending of the sheet and the rotating member, and then the rotating member is driven. By doing so, the sheet can be reliably conveyed.
[0020]
As a result, it is possible to obtain a high-quality paper transport apparatus that can prevent the occurrence of paper non-feed jam.
[0021]
  Also bookIn order to solve the above problems, the invention provides a separation sheet feeding unit that separates and feeds sheets one by one from a sheet bundle placed on a sheet placing table, and a downstream side of the separation sheet feeding unit in the sheet conveying direction. A pair of rotating members that sandwich and convey the separated paper, a single driving unit that drives the rotating member and the separation sheet feeding unit, and a clutch unit that rotates and fixes the rotating member, Control means for driving the driving means and switching the rotation member to a fixed state or a rotating state by operating the clutch means, and fixing the leading edge of the paper separated by the separation paper feeding means In the sheet conveying apparatus in which the sheet is bent by abutting against the nip portion of the rotating member in a state to correct the skew of the sheet, the control unit includes the rotating unit. Immediately after the leading edge of the paper comes into contact with the nip portion of the paper, the clutch means is switched from the fixed state to the rotating state, and then the driving means is stopped when the leading edge of the paper comes into contact with the rotating member. Control is performed so as to drive the driving means after a predetermined time.
[0022]
In that case, the rotating member and the separation sheet feeding unit are driven by a single driving unit, and the rotation member is driven by the clutch unit, whereby the rotating member can be driven independently of the separation sheet feeding unit. Simplification of the configuration of the conveying device and reduction in the number of parts can be achieved, thereby reducing the manufacturing cost.
[0023]
In addition, the driving means is stopped when the leading edge of the paper comes into contact with the nip portion of the rotating member by switching the clutch means from the fixed state to the rotating state immediately before the leading edge of the paper comes into contact with the nip portion of the rotating member. Accordingly, the skew of the sheet can be corrected by causing the sheet to be bent by the rotating member, and the amount of pinching at the leading end of the sheet can be adjusted by adjusting the stop timing of the driving unit. Thereafter, the sheet can be reliably conveyed by driving the rotating member.
[0024]
As a result, it is possible to obtain a high-quality paper transport apparatus that can prevent the occurrence of paper non-feed jam.
[0027]
  Also bookIn order to solve the above-described problems, the present invention has a detecting unit that detects that the leading end of the sheet is close to the rotating member, and the control unit is configured to detect the leading end of the sheet based on a detection signal of the detecting unit. Is controlled so as to switch the clutch means from the fixed state to the rotating state immediately before contacting the rotating member.
[0028]
In that case, the leading edge of the sheet is brought into contact with the nip portion of the rotating member to cause the sheet to bend and correct the skew of the sheet, and then the leading edge of the sheet is sandwiched in the entire nip portion by using the bending of the sheet. be able to.
[0048]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0049]
  1 ~12BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram illustrating a first embodiment of a paper transport device according to the present invention, an image reading device including the paper transport device, and an image forming apparatus including the paper transport device. The image forming apparatus can be applied to a copying machine, a facsimile apparatus, and a printer apparatus, and the image reading apparatus can be applied to a copying machine, a facsimile apparatus, a scanner apparatus, etc. A copier will be described as an example.
[0050]
First, the configuration will be described. 1 to 3, reference numeral 1 denotes an image forming apparatus including a copying machine. A contact glass 2 and a slit glass 3 having a smaller area than the contact glass 2 are provided on the upper surface of a main body 1 a of the image forming apparatus 1. An automatic document feeder (hereinafter simply referred to as ADF) 4 is provided on the upper surface of the main body 1a. The ADF 4 is provided on the upper surface of the main body 1a through a hinge mechanism (not shown) so as to be opened and closed.
[0051]
The ADF 4 is provided with a document table (paper placement table) 5 on the upper surface, and a document bundle P made up of a plurality of documents can be set on the document table 5. A side guide 6 is provided on the document table 5, and the side guide 6 positions the document bundle P in the width direction.
[0052]
A document stopper 7 is provided on the downstream side of the document table 5 in the document transport direction, and the leading end of the document bundle P is brought into contact with the document stopper 7 so that the leading ends of the document bundle P are aligned. ing. Further, the document stopper P moves between an abutting position (shown by a broken line in FIG. 2) abutted against the leading end of the document bundle P and a separation position (shown by a solid line in FIG. 2) separated from the leading end of the document bundle P. It is possible.
[0053]
A document set detection filler 8 is provided in the vicinity of the document stopper 7 at the front end of the document bundle P. The document filler 8 is shown by the document bundle P when the document bundle P is set on the document table 5. 2, the position rises from the position indicated by the broken line to the position indicated by the solid line.
[0054]
Further, when the filler 8 is at the solid line position, the filler 8 is detected by a document set sensor 9 comprising an optical sensor. When the document bundle P is set on the document table 5 and the filler 8 is raised, the document 8 Since the set sensor 9 is released from light shielding by the filler 8, the document set sensor 9 detects that the document bundle P is set on the document table 8 and outputs a signal to the controller 100.
[0055]
The document table 5 is provided with document length sensors 10a and 10b spaced apart in the front-rear direction of the table 5 (document feeding direction). The sensors 10a and 10b detect the length of the document. A detection signal is output to the controller 100.
[0056]
The sensors 10a and 10b are composed of a reflection type sensor or an actuator type sensor that can detect even a single document, and is disposed at a position at which it is possible to determine at least whether the same document is vertical or horizontal.
[0057]
A pickup roller 11 is provided on the document table 5 on the leading end side of the document bundle P. The pickup roller 11 is located between a contact position where the pickup roller 11 is in contact with the document bundle P and a separation position which is separated from the document bundle P. It swings.
[0058]
A paper feeding belt 12 is provided downstream of the pickup roller 11 in the document conveyance direction. The paper feeding belt 12 is bridged by a driving roller 13a and a driven roller 13b and is rotated clockwise by the driving roller 13a. It is designed to move around.
[0059]
A reverse roller 14 is in sliding contact with the paper feed belt, and the reverse roller 14 rotates in a clockwise direction that is a separation direction. Therefore, the uppermost document is separated from the document bundle P conveyed between the paper feed belt 12 and the reverse roller 14.
[0060]
FIGS. 4A and 4B are views showing the swing mechanism of the document stopper 7 and the pickup roller 11.
[0061]
In FIG. 4, reference numeral 15 denotes a call motor, and a motor shaft 15a of the call motor 15 is connected to a gear 17a via a timing belt 16 in which concave and convex grooves are formed on the inner peripheral surface. The gear 17a is connected to an idle gear 17c via a shaft 17b, and a gear 18a and a gear 21a are engaged with the idle gear 17c. A cam 18c is provided on the shaft 18b of the gear 18a, and this cam 18c is brought into contact with and separated from a bracket 7c provided on the shaft 7a of the document stopper 7. The bracket 7c is biased by a spring 7d, and the document stopper 7 is positioned at a position where the document bundle P is abutted and released (see FIG. 4B) when biased by the spring 7d.
[0062]
The document stopper 7 is moved to the abutting position (see FIG. 4A) when the bracket 7c is pressed against the urging force of the spring 7d by the cam 18c. Further, a filler 18d is provided at the end of the shaft 18b, and this filler 18d is detected by a document stopper home position sensor 20 comprising an optical sensor.
[0063]
That is, when the sensor 20 is turned on when the filler 18d is detected and outputs a signal to the controller 100, the controller 100 detects that the document stopper 7 is located at the abutting position, and the sensor 20 does not detect the filler 18d. If the signal is turned OFF and no signal is output to the controller 100, the controller 100 detects that the document stopper 7 is located at the butting release position.
[0064]
On the other hand, a cam 21c is provided at the end of the shaft 21b of the gear 21a. The cam 21c can be brought into contact with and separated from the presser lever 22 of the pickup roller 11. The pickup roller 11 is rotatably supported by the presser lever 22.
[0065]
The pickup roller 11 is pressed by a spring (not shown), and when the presser lever 22 is pressed by the cam 21c, the pickup roller 11 is separated from the document bundle P against the biasing force of the spring. (See FIG. 4B), and when the pressing of the presser lever 22 by the cam 21c is released, the pickup roller 11 is urged by the spring and moves to a position where it comes into contact with the document bundle P. (See FIG. 4A).
[0066]
Further, a filler 21d is provided at the end of the shaft 21b, and this filler 21d is detected by a pickup home position sensor 23 made of an optical sensor.
[0067]
That is, when the sensor 23 detects the filler 21d and is turned on and outputs a signal to the controller 100, the controller 100 detects that the pickup roller 11 is at a position separated from the document bundle, and the sensor 23 detects the filler 21d. If the signal is not turned off and no signal is output to the controller 100 when it stops, the controller 100 detects that it is in a position in contact with the pink up roller 11.
[0068]
The controller 100 drives the call motor 15 when a paper feed start signal is input when a copy start key of an operation unit (not shown) is pressed. At this time, since the calling motor 15 rotates the gears 17a and 17c clockwise through the timing belt 16 in FIG. 4B, the gear 18a rotates counterclockwise and the cam 18c rotates the bracket 7c. The document stopper 7 is retracted from the leading end of the document bundle P.
[0069]
At the same time, the gear 21a rotates counterclockwise so that the cam 21c moves away from the presser lever 22 to release the press of the presser lever 22, so that the pickup roller 11 is urged by the spring and comes into contact with the document bundle P. Move to. As a result, the document bundle can be fed.
[0070]
If the number of document bundles P is small when the pickup roller 11 presses the document bundle P, the drop-up height of the pitch-up roller 11 is large, and the document is placed between the document table 5 and the pickup roller 11. When the cushioning action is small, the drop impact sound of the pickup roller 11 is increased.
[0071]
In the present embodiment, a recess for escaping the pickup roller 11 is formed at the contact point of the pickup roller 11 in the document table 5 so that the roller 11 does not strike the document table 5 directly.
[0072]
On the other hand, registration rollers (rotating members) 24a and 24b are provided on the downstream side of the paper feeding belt 12 in the document conveying direction. The registration roller 24a constitutes a driving roller, and the registration roller 24b constitutes a driven roller.
[0073]
As shown in FIG. 5, a gear 25 is provided at the end of the registration motor 24a. The gear 25 is connected to a pulley 27 via a one-way clutch 26. This pulley 27 is connected to a paper feed motor (drive means, drive motor) 101 via a timing belt 28. When the paper feed motor 101 is driven, the registration roller 24a is rotated only in the paper feed direction by the one-way clutch 26. It is supposed to be.
[0074]
A gear 29a of an electromagnetic clutch (clutch means) 29 is engaged with the gear 25. The electromagnetic clutch 29 is turned on / off based on a command signal from the controller 100, whereby the registration rollers 24a and 24b are rotated. It is switched to a state or a stopped state. The registration rollers 24a and 24b are configured to rotate with a force of about 50 gf, and can be rotated with a bending force of paper.
[0075]
Next, the drive mechanism of the pickup roller 11, the paper feed belt 12, the reverse roller 13, and the registration rollers 24a and 24b will be described with reference to FIGS.
[0076]
6 and 7, a pulley 31a is connected to the paper feed motor 101 via a timing belt 30, and an idler gear 31b provided on the rotary shaft 31 of the pulley 31a is provided on the rotary shaft 32 of the reverse roller 14. Is engaged with the gear 32a. The reverse roller 14 is connected to the rotary shaft 32 via a torque limiter.
[0077]
A gear 32b provided on the rotating shaft 32 of the reverse roller 14 meshes with a gear 33a provided on the rotating shaft 33 of the driving roller 13a that drives the separation belt 12, and a pulley 31c provided on the shaft 31 is As shown in FIG. 5, it is connected to a pulley 27 of a registration roller 24a through a timing belt. The pickup roller 11 is connected to the driven roller 13b via a timing belt 34. The drive roller 13a has a built-in one-way clutch, and the drive force is transmitted to the drive roller 13a only when the paper feed motor 101 is driven forward.
[0078]
Thus, in the present embodiment, the pickup roller 11, the paper feed belt 12, the reverse roller 13, and the registration rollers 24a and 24b are driven by the single paper feed motor 101.
[0079]
Here, a method for separating a document will be described.
[0080]
When the paper feed motor 101 is driven, the pickup roller 11 in contact with the original bundle P rotates in the clockwise direction, and the original located at the top of the original bundle P is fed toward the feed belt 12. At this time, the paper feeding belt 12 is wound with a predetermined tension between the rollers 13a and 13b, and is supplied to the nip portion of the paper feeding belt 12 and the reverse roller 14 that is in sliding contact with the paper feeding belt 12. The
[0081]
At this time, if two or more documents are supplied to the nip portion of the paper feed belt 12 and the reverse roller 14, the reverse roller 14 rotates the paper feed belt 12 because the reverse roller 14 has a built-in torque limiter. Rotate with.
[0082]
By setting the following force to be lower than the torque force of the torque limiter, the reverse roller 14 rotates in the clockwise direction, which is the original driving direction, and pushes back the excess document so that multiple documents are fed. Is prevented.
[0083]
In the present embodiment, the pickup roller 11, the paper feeding belt 12, and the reverse roller 14 constitute a separation paper feeding unit.
[0084]
On the other hand, the separated document is detected by an abutment sensor (detection means) 35 provided upstream of the registration rollers 24a and 24b in the document conveyance direction, and this sensor 35 detects the leading edge of the document. Thus, a signal is output to the controller 100.
[0085]
The controller 100 counts the drive pulse of the paper feed motor 101 after the sensor 35 detects the leading edge of the document, and this drive pulse is a predetermined pulse (the distance + α between the position of the sensor 35 and the nip portion of the registration rollers 24a and 24b). ) Is stopped, the drive of the paper feed motor 101 is stopped, the leading edge of the document is brought into contact with the nip portion of the registration rollers 24a and 24b set to the stopped state by the electromagnetic clutch 29, and the document is bent. Correcting document skew (skew)
[0086]
Thereafter, the controller 100 turns on the electromagnetic clutch 29 to drive the registration roller 24a, so that the document is nipped and conveyed by the registration rollers 24a and 24b.
[0087]
This document is sandwiched between a large-diameter reading and conveying roller (conveying driving roller) 36 and a pressure roller (conveying driven roller) 36a driven by the reading motor 102 and conveyed through the reverse path 37. Further, a leading edge detection sensor 38 is provided on the upstream side in the document conveyance direction of the reading conveyance roller 36 and the pressure roller 36a, and the registration rollers 24a and 24b as described above until the leading edge of the document is detected by the sensor 38. The registration rollers 24a and 24b are rotated at a high speed in order to recover the extra time that has been waiting.
[0088]
When the leading edge of the document is detected by the document reading sensor 38, the controller 100 reduces the speed of the registration roller 24a to the speed of the reading and conveying roller 36, and performs this operation between successive documents. A predetermined document interval is maintained.
[0089]
On the other hand, the width of the document that has passed through the registration rollers 24a and 24b is detected by the size detection sensor group 39 in the direction orthogonal to the conveyance direction. The controller 100 detects the width signal and the document length sensor 10a. 10b, the correct document size is grasped based on the combination of the length signals obtained by 10b.
[0090]
A registration sensor 40 is provided downstream of the reading and conveying roller 36 and the pressure roller 36a. When the registration sensor 40 detects the leading edge of the document, it outputs a signal to the controller 100, and the controller 100 is based on this detection signal. Then, the driving of the reading motor 102 is stopped, the reading conveyance roller 36 is stopped, and the input of an image alignment signal on the image forming side is waited for.
[0091]
When an image alignment signal is input to the controller 100 from the main body 1 a of the image forming apparatus 1, the reading motor 102 is driven to rotate the reading conveyance roller 36. At this time, the document is nipped between the reading conveyance roller 36 and the pressure roller (conveyance driven roller) 36 b and conveyed toward the slit glass 3.
[0092]
A white background plate 41 is disposed on the slit glass 3 with a predetermined interval, and the document passes between the contact glass 3 and the white background plate 41. At this time, the document is read by the optical system provided in the image forming apparatus 1.
[0093]
Specifically, the image forming apparatus 1 below the slit glass 3 is provided with a scanner (image reading means) 42 formed of an image sensor. The scanner 42 is moved in the left-right direction in FIG. It is supposed to move.
[0094]
This driving device is controlled by a main body control unit 111. When reading image information of a document set on the contact glass 2, the scanner 42 is scanned below the contact glass 2 and the slit glass is scanned. The scanner 42 is stopped below the slit glass 3 when reading the image information of the document conveyed onto the sheet 3.
[0095]
The image information of the original read by the scanner 42 is stored as image data in a memory of the main body control unit 111 (not shown).
[0096]
Further, in the present embodiment, a measure is taken so that the conveyance gap of the document conveyance unit of the slit glass 3 is as narrow as possible and the degree of freedom of the document is minimized. As the method, a flexible guide plate (not shown) is pulled out from the inner surface on the downstream side of the inversion path 37 toward the white background plate 41 to fill the gap.
[0097]
Further, since the white background plate 41 is pressed onto the slit glass 3 with a predetermined elastic force with a gap of about 0.5 mm ± 0.2 mm, errors in the depth direction are also suppressed.
[0098]
Further, the surface of the slit glass 3 is subjected to a surfactant (silicone activator) treatment in order to make it difficult for ink and the like to adhere and adhere. Further, the above-described flexible guide is extended to the vicinity of the reading point, and the document surface does not positively contact the slit glass 3 at the reading position, and the leading end of the document is wiped near the reading point of the slit glass 3 (the slit glass at the leading end). The action of scraping off the foreign matter on the three surfaces).
[0099]
A document to be read by the slit glass 3 is conveyed by being sandwiched between a reading conveyance roller 36 and a pressure roller (conveyance driven roller) 36c through a stepped pickup guide 43. Since the pressure roller 36b and the pressure roller 36c are commonly driven (driven) by the reading and conveying roller 36, the feeding speed and the drawing speed are the same, and the linear speed of the original is kept constant to reduce the occurrence of a shock at the delivery of the original. can do. In the present embodiment, the reading and conveying roller 36 and the pressure rollers 36a to 36c constitute a conveying unit.
[0100]
A document sandwiched between the reading and conveying roller 36 and the pressure roller 36c and coming out of the slit glass 3 has a contact image sensor (reading means) 44 having a reading surface set on the lower surface, and a sensor 44 and a predetermined sensor on the lower surface of the sensor 44. It passes between the pressing members 45 arranged at intervals, and at this time, the back side of the document is read by the sensor 44 and is electrically converted in the same manner as the document surface and stored in a memory device (not shown).
[0101]
The pressing member 45 has a function as a reference for shading and a function as a white background plate. As the pressing member 45, a plate-shaped guide member is used, but it may be constituted by a rotating body.
[0102]
A document read by the contact image sensor 44 is discharged to a document stacker unit (paper discharge table) 46. The document stacker unit 46 is provided below the document table 5 and is inclined upward from the upstream side to the downstream side in the document discharge direction to prevent the document from jumping out. It is possible to improve stackability by aligning the discharged documents.
[0103]
Thus, the image of the original read by the scanner 42 and the image sensor 44 is transferred to the transfer paper by the image forming means.
[0104]
Hereinafter, this transfer method will be described.
[0105]
The main body control unit 111 forms an electrostatic latent image on the photosensitive drum 202 constituting the image forming unit 201 by using the writing system 200 with the image data, and the charging unit 203, the exposure unit 204, and the developing unit constituting the image forming unit 201. A visible image of the toner is formed on the photosensitive drum 202 by the cooperation of the unit 205.
[0106]
On the other hand, the transfer paper fed from the paper feed system 206 is conveyed to the image forming means 201 by the transfer paper conveying means including the roller pairs 210 and 211, and one of the transfer papers is transferred by the transfer unit 207 constituting the image forming means 201. The toner is transferred onto the surface of the sheet, and the transfer sheet on which the fixing by the fixing system 208 has been completed is conveyed to the reverse discharge unit 209.
[0107]
Here, the I path in the reverse paper discharge unit 209 is a straight paper discharge path for the transfer paper to the outside of the image forming apparatus 1, and the II path is a path through which the transfer paper is reversed and discharged in the reverse paper unit 209. In the path III, after the transfer paper is reversed in the reverse discharge unit 209, the transfer paper is re-fed to the double-sided tray, and the other side of the transfer paper is transferred through the image forming process described above. , And discharged through the I path to the outside of the image forming apparatus 1.
[0108]
Here, when originals of different sizes are mixed, the original length sensors 10a and 10b on the original table 5 cannot determine the original size. The size is determined for the first time when the image is separated from the original bundle P and becomes completely independent.
[0109]
For this reason, it is necessary to determine the document size before reading the document. In this case, the maximum document between the first document rear end position after separation of the document path configuration and the position of the registration sensor 40 before reading is determined. It is necessary to set the length to ½ or more of the length.
[0110]
If this is satisfied, the document setting position needs to be greatly separated from the reading position, and the part including the document table 5 and the conveyance path becomes large, and the entire ADF 4 becomes wide.
[0111]
Therefore, in order to reduce the ADF 4, it is necessary to devise detection of the document length when different sizes are mixed. In this embodiment, when the document size cannot be determined before starting the reading when mixed with different sizes, the document is not read in the first conveyance, but the document is passed only for reading the size, and the reversing unit is set. Thus, a method of simultaneously reading the front and back surfaces at the time of the second reading passage is adopted.
[0112]
This will be specifically described below.
[0113]
In the present embodiment, the transport operation until the first discharge of the document is the same as the transport method of the document of the same size except that reading is not performed. However, when the document is discharged through the slit glass 3, A reversing switching claw 50 that is controlled to be switched by a reversing switching solenoid 49 before the front end of the sheet is exposed to the document stacker unit 46 by the discharge rollers 48 and 48a driven by the reading motor 102 is shown in the direction of the broken line in FIG. The document is moved and conveyed through the switchback path 51.
[0114]
The reversal switching solenoid 49 is driven by the controller 100, and the controller 100 indicates the position where the reversing switching claw 50 is indicated by a broken line based on the signal of the sensor 52 when the paper discharge sensor 52 detects the leading edge of the document. Move to.
[0115]
The document conveyed to the switchback path 51 is fed by the switchback roller pair 53 driven by the reversing motor 103 until the trailing edge of the document passes the paper discharge rollers 48 and 48a. Is detected by the paper discharge sensor 52 until a predetermined time has elapsed.
[0116]
The controller 100 counts the driving pulse of the reading motor 102 after the trailing edge of the document is detected by the paper discharge sensor 52, and this driving pulse corresponds to the trailing edge of the document sufficiently entering the switchback path 51. When the number of pulses is reached, the driving of the reading motor 102 is stopped.
[0117]
Thereafter, the reverse switching solenoid 49 is driven to move the reverse switching claw 50 to the position indicated by the solid line so that the reverse switching claw 50 is directed to the nip portion of the paper discharge rollers 48 and 48b. Thereafter, the reversing motor 103 is driven in reverse to rotate the switchback roller pair 53 counterclockwise and reversely, thereby conveying the document toward the nip portion of the discharge rollers 48 and 48b.
[0118]
At this time, since the driving of the reading motor 102 is stopped, the leading edge of the document comes into contact with the nip portion of the paper discharge rollers 48 and 48b and the document is bent, whereby the skew of the document is corrected.
[0119]
Thereafter, by driving the reading motor 102, the original is sandwiched between the paper discharge motors 48 and 48b and conveyed to the slit glass 3 and the image sensor 44 through the return path 54 and the reverse path 37, and the images on the front and back surfaces are transferred. Read. Further, when the trailing edge of the document is detected by the reversing sensor 80, the driving of the reversing motor 103 is stopped.
[0120]
At this time, since the document is in a state in which the back side and the front side are reversed, the reading order is the back side first and the front side later, and the ADF 4 side needs to change the page order.
[0121]
The reading operation is completed as described above. However, if the original is discharged to the original stacker unit 46 as it is, the page order will not be normal, and after performing the reversal process similar to that described above, Paper is discharged to the document stacker unit 46. The above-described conveyance only for size reading and conveyance only for page alignment is configured to send at the highest conveyance speed of the ADF 4 for the conveyance operation without image reading, thereby reducing the document conveyance loss time. I try to reduce it.
[0122]
On the other hand, the controller 100 of this embodiment constitutes a control means, and when the leading edge of the document comes into contact with the nip portions of the registration rollers 24A and 24b, the paper feed motor 101 is stopped and the electromagnetic clutch 29 is fixed ( Switching from the ON state to the rotating state (OFF) and driving the paper feed motor 101 after a certain period of time makes it possible to correct the skew of the document and pinch the leading edge of the document.
[0123]
  Next, how to correct document skew and pinch the documentExampleWill be described with reference to FIGS. FIG. 8 is a flowchart showing skew correction and document leading edge pinching processing, FIG. 9 is a timing chart when the separating paper feeding means and the registration roller are driven, and FIG. 10 is a document skew correcting time and document leading edge clamping state. It is a figure which shows operation | movement of a separate paper feeding means and a registration roller. Here, since the procedure from document feeding to paper ejection has been described above, only the skew correction and the method for pinching the leading edge of the document will be described in detail.
[0124]
  First, when the original bundle P is set on the original table 5 so that the leading end of the original bundle P abuts against the original stopper 7, the original bundle filler 8 is pressed against the original bundle P and the position indicated by the broken line is indicated by the solid line position.OnTo rise. At this time, the filler 8 is detected by the document set sensor 9.RenaTherefore, a signal indicating that the document bundle P has been set is transmitted from the set sensor 9 to the controller 100.
[0125]
Next, when the copy start key of the operation unit is pressed and a paper feed start signal is input to the controller 100, the controller 100 drives the calling motor 15 to rotate forward. At this time, the calling motor 15 rotates the cam 18c via the timing belt 16, the gears 17a and 17b, and the gear 18a, thereby releasing the pressing of the bracket 7c.
[0126]
At this time, the bracket 7c is urged by the spring 7d to move the document stopper 7 to the butting release position of the document bundle P. At this time, since the home position sensor 20 is turned off without detecting the filler 18d provided at the end of the shaft 18b, the controller 100 detects that the document stopper 7 is located at the butting release position.
[0127]
Further, when the calling motor 15 rotates the cam 21c via the timing belt 16, the gears 17a, 17b, and the gear 21a, the cam 21c is separated from the presser lever 22 that supports the pickup roller 11, so that the pickup roller 11 is moved by a spring. Is moved to a position in contact with the document bundle P. (See FIG. 10 (a)).
[0128]
At this time, since the home position sensor 23 is turned off without detecting the filler 21d provided at the end of the shaft 21b, the controller 100 detects that the pickup roller 11 is in a position where it abuts against the document bundle. To do.
[0129]
Next, the electromagnetic clutch 29 is turned on to switch the registration rollers 24a and 24b to a fixed state, and the paper feed motor 101 is driven forward. When the paper feed motor is driven, the pickup roller 11 that is in contact with the document bundle P rotates clockwise, and feeds the document located at the top of the document bundle P toward the paper feed belt 12 to be fed. Supplied to the nip portion of the paper belt 12 and the reverse roller 14.
[0130]
At this time, if two or more documents are supplied to the nip portion of the paper feed belt 12 and the reverse roller 14, the reverse roller 14 rotates the paper feed belt 12 because the reverse roller 14 has a built-in torque limiter. Rotate with.
[0131]
Since the follower force is set to be lower than the torque force of the torque limiter, the reverse roller 14 rotates in the clockwise direction, which is the original driving direction, and pushes back the excess document, thereby causing The paper is conveyed toward the registration rollers 24a and 24b while preventing the feeding (the above processing is step S1).
[0132]
Next, it is determined whether or not the leading edge of the document is detected by the abutting sensor 35 (step S2). When the leading edge of the document is detected by the abutting sensor 35, the controller 100 determines whether the leading edge of the document is based on this detection signal. 101 is decelerated and the drive pulse of the paper feed motor 101 is counted. When this drive pulse reaches a predetermined pulse (distance between the position of the sensor 35 and the nip portion of the registration rollers 24a and 24b + α), the paper is fed. The drive of the motor 101 is stopped. (Step S3).
[0133]
At this time, as shown in FIG. 10B, the front end of the original P1 is brought into contact with the nip portions of the registration rollers 24a and 24b set to the stopped state by the electromagnetic clutch 29, and the original P1 is bent to thereby bend the original P1. Correct the skew.
[0134]
Next, the controller 100 monitors a stop signal issued from a program for rotating the paper feed motor 101, and while this stop signal is detected (15 msec for the first original, the second and subsequent originals). The electromagnetic clutch 29 is turned off for only 50 msec (step S4). At this time, as shown in FIG. 10C, the registration rollers 24a and 24b are rotated by the bending of the document P1, and the leading end of the document P1 is sandwiched between the nip portions of the registration rollers 24a and 24b.
[0135]
Next, when the controller 100 detects that the stop signal is released, the controller 100 drives the reading motor 102 in the reverse direction and drives the calling motor 15.
[0136]
When the calling motor 15 is driven, the cam 21c rotates via the timing belt 16, the gears 17a, 17b, and the gear 21a, so that the cam 21c presses the presser lever 22 that supports the pickup roller 11 to attach the spring. The pickup roller 11 is separated from the document bundle P against the force.
[0137]
The controller 100 also reversely drives the paper feed motor 101 simultaneously with the release of the stop signal, and does not transmit the driving force to the paper feed belt 12 that is driven only when the paper feed motor 101 is rotated forward by the one-way clutch. The documents 24a and 24b are driven to convey the document toward the reading and conveying roller 36. As a result, the document is conveyed to the slit glass 3 by the reading conveyance roller 36.
[0140]
In the present embodiment, the paper feed motor 101 is driven to decelerate from when the abutment sensor 35 detects the front end of the document, and the drive motor 101 counts the driving pulses during the deceleration drive, so that the front end of the document is detected. Since the contact with the nip portion of the registration rollers 24a and 24b is detected, it is possible to prevent the original such as thin paper from coming into strong contact with the nip portion of the registration rollers 24a and 24b and damaging the original.
[0141]
Further, since the paper feed motor 101 is driven by the distance + α between the detection position of the leading edge of the document and the nip portions of the registration rollers 24a and 24b, the document can be reliably bent and the skew of the document can be reduced. It can be corrected.
[0142]
Further, since the skew of the original is corrected by the registration rollers 24a and 24b, the original skew can be corrected immediately after the original is separated from the original bundle P, and the original can be stably conveyed to the slit glass 3. Can do.
[0143]
Further, since the clutch means is composed of the electromagnetic clutch 29, the registration rollers 24a and 24b can be easily switched between the rotation state and the stop state.
[0144]
In this embodiment, the document stacker unit 46 from which the document is discharged is provided below the document table 5, and the document stacker unit 46 is inclined upward from the upstream side toward the downstream side in the document discharge direction. Therefore, it is possible to prevent the document from jumping out and to improve the stackability by aligning the discharged document.
[0145]
In this embodiment, since the ADF 4 capable of reducing the manufacturing cost by achieving simplification and reducing the number of parts is mounted on the image forming apparatus 1, the cost of the image forming apparatus 1 is reduced correspondingly. Can do.
[0146]
  Furthermore, the large-diameter reading and conveying roller 36 is disposed around the reading and conveying roller 36.InA plurality of pressure rollers 36 a to 36 c slidably in contact with the reading conveyance roller 36WhenTherefore, the original can be conveyed by the large-diameter reading and conveying roller 36, and the original can be stably conveyed while keeping the linear speed of the original constant.
[0147]
  Figures 11 and 12It is a figure which shows the control of this embodiment which a controller performs.
[0148]
In this embodiment, the controller 100 drives the paper feed motor 101 for a predetermined time after switching the electromagnetic clutch 29 from the fixed state to the rotating state when the leading edge of the document comes into contact with the nip portions of the registration rollers 24a and 24b. Then, control is performed so that the paper feed motor 101 is driven after a predetermined time.
[0149]
Hereinafter, the control will be described based on the flowchart of FIG. 11 and the timing chart of FIG. The timing chart of FIG. 12 shows the timing of the paper feed motor 101, the electromagnetic clutch 29, and the reading motor 102, and other timings are the same as those of FIG.
[0150]
First, in step S11, the same processing as in step S1 of the first embodiment is performed to separate and feed the document, and then it is determined whether or not the leading edge of the document is detected by the abutting sensor 35 (step S12). . When the leading edge of the document is detected by the abutting sensor 35, the controller 100 decelerates the sheet feeding motor 101 based on this detection signal and counts the driving pulse of the sheet feeding motor 101, and this driving pulse is a predetermined pulse ( When the setting of the position of the sensor 35 and the distance to the nip portions of the registration rollers 24a and 24b + α) is reached, the driving of the paper feed motor 101 is stopped. (Step S13).
[0151]
Next, after the electromagnetic clutch 29 is turned off (step S14), the paper feed motor 101 is driven in reverse, and the paper feed motor 101 is driven for 10 pulses only (feed amount of one pulse: approximately 20 msec from 1.66 mm from 0.16 mm). Just rotate. The breakdown of these 10 pulses is set to 4 pulses for through-up, 1 pulse for constant speed, and 5 pulses for through-down.
[0152]
Next, when the controller 100 detects that the stop signal is released, the controller 100 drives the reading motor 102 in the reverse direction and also drives the calling motor 15 to convey the document toward the slit glass 3.
[0153]
  Thus, in this embodiment,Registration roller twenty four a, twenty four b and separating paper feeding means into a single paper feeding motor 101 And the registration roller twenty four a, twenty four b for electromagnetic clutch 29 By driving with a registration roller twenty four a, twenty four b can be driven independently of the separation sheet feeding means, and the structure of the ADF 4 can be simplified and the number of parts can be reduced, thereby reducing the manufacturing cost.
  In this embodiment,By stopping the paper feed motor 101 when the leading edge of the document comes into contact with the nip portions of the registration rollers 24a and 24b, the registration rollers 24a and 24b cause the document to bend, thereby correcting the skew of the document. Then, by switching the electromagnetic clutch 29 from the fixed state to the rotating state and stopping the sheet feeding motor 101 by driving the registration rollers 24a and 24b for 10 pulses, the deflection of the original and the rotation of the registration rollers 24a and 24b are utilized. Thus, the leading edge of the document can be sandwiched in the entire nip portion, and then the document can be reliably conveyed by driving the registration rollers 24a and 24b.As a result, it is possible to obtain a high-quality ADF 4 that can prevent the occurrence of a document unfeed jam.
[0154]
  FIG. 13 is a schematic diagram of a sheet conveying apparatus according to the present invention, an image reading apparatus including the sheet conveying apparatus, and an image forming apparatus including the sheet conveying apparatus.2It is a figure which shows embodiment. The present embodiment is characterized by the control executed by the controller, and the apparatus configuration is the same as that of the first embodiment. Therefore, description will be made with reference to the drawings of the first embodiment.
[0155]
In the present embodiment, the controller 100 switches the electromagnetic clutch 29 from the fixed state to the rotating state immediately before the leading edge of the document comes into contact with the nip portions of the registration rollers 24a and 24b, and then the leading edge of the document on the registration rollers 24a and 24b. The sheet feeding motor 101 is stopped when the sheet abuts, and then the sheet feeding motor is controlled to be driven after a predetermined time.
[0156]
Hereinafter, the control will be described based on the flowchart of FIG.
[0157]
First, in step S21, the same processing as in step S1 of the first embodiment is performed to separate and feed the document, and then it is determined whether or not the leading edge of the document is detected by the abutting sensor 35 (step S22). .
[0158]
When the leading edge of the document is detected by the abutting sensor 35, the controller 100 decelerates the paper feed motor 101 based on this detection signal and counts the drive pulses of the paper feed motor 101 (step S23). Is set to a predetermined pulse (the position of the sensor 35 and the distance between the nip portions of the registration rollers 24a and 24b + α), that is, whether or not the through-down of the paper feed motor 101 is completed (step S24). Immediately before the end of through-down of the paper feed motor 101, the electromagnetic clutch 29 is turned off and the leading edge of the document is sandwiched between the nip portions of the registration rollers 24a and 24b (step S25).
[0159]
In this embodiment, the electromagnetic clutch 29 is turned off while the paper feed motor 101 is rotating. However, if the electromagnetic clutch 29 is turned off quickly, the registration rollers 24a, Since there is a possibility that the front end of the original passes through the nip portions of the registration rollers 24a and 24b by extruding 24b, it is necessary to turn off the electromagnetic clutch 29 with the front end of the original sufficiently aligned.
[0160]
In the present embodiment, the controller 100 is configured to turn off the electromagnetic clutch 29 based on a motor through down end signal issued from a control program for the paper feed motor 101.
[0161]
In the current software configuration, since the end of the through-down is not the stop of the paper feed motor 101, in this embodiment, programming is performed so that the paper feed motor 101 is rotated by three pulses after the through-down final address data and then stopped. . In addition, if the software configuration is such that the number of remaining steps during the down-down can be determined, the electromagnetic clutch 29 may be released at any remaining number of pulses. It is possible to make fine adjustments to determine how many millimeters the tip of the sheet is inserted.
[0162]
As described above, in this embodiment, by switching the electromagnetic clutch 29 from the fixed state to the rotating state immediately before the leading edge of the document comes into contact with the nip portions of the registration rollers 24a and 24b, the document is placed in the nip portions of the registration rollers 24a and 24b. By stopping the paper feed motor 101 when the leading end abuts, the document rollers can be bent by the registration rollers 24a and 24b to correct the skew of the document, and the stop timing of the paper feed motor 101 can be set. By adjusting, the amount of pinching at the leading edge of the document can be adjusted. Thereafter, the document can be reliably conveyed by driving the registration rollers 24a and 24b.
[0163]
In each of the above embodiments, the back surface of the document is read by the contact image sensor 44. However, since the image sensor 44 is expensive, the reverse surface is used to read the back surface of the document without the image sensor 44. Can do.
[0164]
Hereinafter, this method will be described.
[0165]
The document whose surface has been read by the scanner 42 on the slit glass 3 is switched back by the switchback roller pair 53 in the switchback path 51 and then returned to the slit glass 3 via the return path 54 and the reverse path 37. The back side of the document is read. Thereafter, the sheet is switched back again by the switchback roller pair 53 in the switchback path 51 for page alignment, and then discharged onto the document stacker unit 46 through the return path 54 and the reverse path 37.
[0166]
If a double-sided copy is taken from a double-sided original as described above in the absence of the image sensor 44, the document transport time becomes long and the copy productivity decreases, but in this embodiment, multiple sheets are taken as a countermeasure. This method employs a method in which the original document is fed into the ADF 4 and the inter-paper loss is reduced by alternately combining image reading and document reverse discharge.
[0167]
The method will be specifically described below.
[0168]
First, the first original is fed to the slit glass 3 and the first page (front surface) image is read by the scanner 42, and then the original is conveyed to the switchback path 51.
[0169]
At this time, the controller 100 counts the driving pulse of the reading motor 102 after the trailing edge of the document is detected by the paper discharge sensor 52, and the driving pulse has sufficiently entered the trailing edge of the document into the switchback path 51. When the number of pulses is equal to, the driving of the reading motor 102 is stopped.
[0170]
Thereafter, the reverse switching solenoid 49 is driven to move the reverse switching claw 50 to the position indicated by the solid line so that the reverse switching claw 50 is directed to the nip portion of the paper discharge rollers 48 and 48b. Thereafter, the reversing motor 103 is driven in reverse to rotate the switchback roller pair 53 counterclockwise and reversely, thereby conveying the document toward the nip portion of the discharge rollers 48 and 48b.
[0171]
At this time, since the driving of the reading motor 102 is stopped, the leading edge of the document comes into contact with the nip portion of the paper discharge rollers 48 and 48b and the document is bent, whereby the skew of the document is corrected.
[0172]
Thereafter, by driving the reading motor 102, the original is sandwiched between the paper discharge motors 48 and 48b and conveyed to the slit glass 3 and the image sensor 44 through the return path 54 and the reverse path 37, and the second page (back surface). ) Is read, the document is conveyed to the switchback path 51.
[0173]
Further, before and after the operation of transporting the document to the switchback path 51, the second document is fed, and the image on the third page (the surface of the second document) is read on the slit glass 3. On the other hand, the first original is reversely discharged from the switchback path 51 via the return path 54 and the reverse path 37. At this time, the first document and the second document are conveyed by the reading conveyance roller 36.
[0174]
Next, after reading the surface of the second document, the document is transported to the switchback path 51 and transported from the switchback path 51 to the reverse path 37 via the return path 54. When detected by the sensor 40, the first document is discharged to the document stacker unit 46.
[0175]
Next, after the second original is returned from the switchback path 51 to the slit glass 3 via the return path 54 and the reverse path 37, the image on the fourth page (the back side of the second original) is read. The document is conveyed to the switchback path 51.
[0176]
Further, the third original is fed before and after the operation of conveying the second original to the switchback path 51, and the image of the fifth page (the surface of the third original) on the slit glass 3 is supplied. The second original is reversely discharged from the switchback path 51 via the return path 54 and the reverse path 37.
[0177]
Next, after reading the image of the sixth page (the back side of the third document), this document is transported to the switchback path 51 and transported from the switchback path 51 to the reverse path 37 via the return path 54. When the leading edge of the original is detected by the registration sensor 40, the second original is discharged to the original stacker unit 46.
[0178]
In this way, by performing the processing with the document discharge operation already completed between the reading operation on the front surface and the reading operation on the back surface, the loss time between sheets in the reverse discharging operation without reading is minimized. Can do.
[0179]
Note that this processing is possible only for a document having a length that fits between the switchback roller pair 53 and the registration sensor 40.
[0180]
【The invention's effect】
According to the present invention, the rotating member and the separation feeding unit are driven by a single driving unit, and the rotation member is driven by the clutch unit, so that the rotating member can be driven independently of the separation feeding unit. In addition, the configuration of the sheet conveying device can be simplified and the number of parts can be reduced to reduce the manufacturing cost.
[0182]
In addition, by stopping the drive means after a certain period of time has elapsed since the leading edge of the paper comes into contact with the nip portion of the rotating member, the rotating member deflects the paper to correct the skew of the paper, and the clutch means is fixed. By switching from the rotating state to the rotating state, the rotating member is driven and stopped for a certain period of time, so that the leading edge of the sheet is sandwiched in the entire nip portion using the bending of the sheet and the rotating member, and then the rotating member is driven. By doing so, the sheet can be reliably conveyed. As a result, it is possible to obtain a high-quality paper transport apparatus that can prevent the occurrence of paper non-feed jam.
[0183]
In addition, the driving means is stopped when the leading edge of the paper comes into contact with the nip portion of the rotating member by switching the clutch means from the fixed state to the rotating state immediately before the leading edge of the paper comes into contact with the nip portion of the rotating member. Accordingly, the skew of the sheet can be corrected by causing the sheet to be bent by the rotating member, and the amount of pinching at the leading end of the sheet can be adjusted by adjusting the stop timing of the driving unit. Thereafter, the sheet can be reliably conveyed by driving the rotating member. As a result, it is possible to obtain a high-quality paper transport apparatus that can prevent the occurrence of paper non-feed jam.
[0185]
In addition, a detecting unit that detects that the leading end of the sheet is close to the rotating member is provided, and the control unit rotates the clutch unit from the fixed state immediately before the leading end of the sheet contacts the rotating member based on the detection signal of the detecting unit. Since the control is performed so as to switch to the state, the leading edge of the sheet is brought into contact with the nip portion of the rotating member to cause the sheet to bend and correct the skew of the sheet. The leading edge of the paper can be sandwiched across the entire area.
[Brief description of the drawings]
FIG. 1 is a sheet conveying apparatus according to the present invention.SetIt is a figure which shows 1st Embodiment,A paper transport device is installed.1 is a schematic configuration diagram of an image forming apparatus.
FIG. 2 is a schematic configuration diagram of an ADF provided in the image forming apparatus according to the first embodiment.
FIG. 3 is a block diagram illustrating a circuit configuration of the ADF according to the first embodiment.
FIGS. 4A and 4B are diagrams illustrating a document stopper and a pickup roller driving mechanism according to the first embodiment; FIGS.
FIG. 5 is a diagram illustrating a driving mechanism of a registration roller according to the first embodiment.
FIG. 6 is a top view of a drive mechanism for a pickup roller, a paper feed belt, a reverse roller, and a registration roller according to the first embodiment.
FIG. 7 is a side view of a drive mechanism for a pickup roller, a paper feed belt, a reverse roller, and a registration roller according to the first embodiment.
[Fig. 8]TheFor cue correction and document pinchingAn exampleIt is a flowchart.
FIG. 9MinWhen the paper feeding means and registration rollers are drivenAn exampleIt is a timing chart.
FIG. 10 is a diagram illustrating operations of the separation paper feeding unit and the registration roller when correcting the skew of the document and sandwiching the leading edge of the document according to the first embodiment.
[Figure 11]The first embodiment10 is a flowchart of cue correction and document tip nipping processing.
[Figure 12] First16 is a timing chart at the time of driving the separation sheet feeding unit and the registration roller according to the embodiment.
FIG. 13 is a sheet conveying device according to the present invention.SetFirst2FIG. 6 is a diagram illustrating an embodiment, and a flowchart of skew correction and document tipping processing.
[Explanation of symbols]
  1 Image forming device
  3 Slit glass
  4 ADF
  5 Document table (paper placement table)
  11 Pickup roller (separate paper feeding means)
  12 Separation belt (separation paper feeding means)
  14 Reverse roller (separate paper feeding means)
  24a, 24b Registration roller (rotating member)
  29 Electromagnetic clutch (clutch means)
  35 Butting sensor (detection means)
  36 Reading conveyance roller (conveyance means)
  36a-36c Reading conveyance roller (conveyance means)
  42 Scanner (image reading means)
  44 Contact image sensor (reading means)
  46 Document stacker (paper output tray)
  100 controller (control means)
  101 Paper feed motor (drive means, drive motor)
  201 Image forming means
  210, 211 Roller pair (transfer paper transport means)
  P Document bundle (paper bundle)

Claims (3)

A separation sheet feeding unit that separates and feeds sheets one by one from a sheet bundle placed on the sheet loading table, and is provided on the downstream side of the separation sheet feeding direction with respect to the sheet conveyance direction, and holds the separated sheets. A pair of rotating members, a single driving unit for driving the rotating member and the separation paper feeding unit, a clutch unit for rotating and fixing the rotating member, and driving the driving unit, and the clutch Control means for switching and controlling the rotating member to a fixed state or a rotating state by operating means,
Paper conveyance in which the leading edge of the paper separated by the separation paper feeding means abuts against the nip portion of the rotating member in a fixed state, thereby causing the paper to bend and correct the skew of the paper. In the device
Wherein the control means, the tip of the sheet to the nip portion of the rotating member stops said drive means after a predetermined time has elapsed from contact, after switching in rotation the clutch means from the fixed state, the driving means Is driven for a predetermined time and then stopped, and then, the control is performed to drive the driving means after a predetermined time . A separation sheet feeding unit that separates and feeds sheets one by one from a sheet bundle placed on the sheet loading table, and is provided on the downstream side of the separation sheet feeding direction with respect to the sheet conveyance direction, and holds the separated sheets. A pair of rotating members, a single driving unit for driving the rotating member and the separation paper feeding unit, a clutch unit for rotating and fixing the rotating member, and driving the driving unit, and the clutch Control means for switching and controlling the rotating member to a fixed state or a rotating state by operating means,
Paper conveyance in which the leading edge of the paper separated by the separation paper feeding means abuts against the nip portion of the rotating member in a fixed state, thereby causing the paper to bend and correct the skew of the paper. In the device
The control means switches the clutch means from the fixed state to the rotating state immediately before the leading edge of the sheet comes into contact with the nip portion of the rotating member, and then when the leading edge of the sheet comes into contact with the rotating member, A sheet conveying apparatus characterized in that the driving means is stopped, and then the driving means is controlled to be driven after a predetermined time . Detecting means for detecting that the leading edge of the paper is close to the rotating member;
The control means performs control so that the clutch means is switched from a fixed state to a rotating state immediately before the leading edge of the paper contacts the rotating member based on a detection signal of the detecting means. The sheet conveying device according to claim 2 .

Images