JP2006188339A - Automatic document feeder and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic document feeder capable of butting a tip of an original to a roller stopped immediately before the reading without waiting for the preceding original passing through the reading position, enhancing the skew quality and the productivity, and suppressing an increase of the size of a machine and an increase of the cost by providing a transmission control member such as a clutch on a driving system on the upstream side of a reading drive system (a reading upstream (inlet) conveying roller and a reading downstream (outlet) conveying roller). <P>SOLUTION: In the automatic document feeder of the type for reading an image while conveying a sheet original, a transmission control member 47 capable of controlling the drive transmission is provided on conveying roller pairs 16 immediately before the reading position, the driving origin is uncoupled at the time when a rear end of the preceding original during the reading passes through the conveying roller pairs 16 immediately before the reading position, the next original is butted to the conveying roller pairs 16 immediately before the reading position in a stopped state, and the next original is conveyed, and the butt-skew is corrected. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an improvement in a sheet-through type automatic document feeder (hereinafter referred to as ADF) that reads an image while a sheet document is being conveyed. It is related to ADF that can do.

There are various types of image forming apparatuses such as copiers, printers, facsimiles, etc., and document feeders that are equipped in the image reading apparatus and transport the document to the reading unit. ) And the like, and a document feeding device in which the sheet is separated and conveyed one by one by a reverse roller is known (for example, Patent Document 1). Thru 3).
In Patent Document 1, a document is fed before the reading start signal from the main body control unit is detected (next document advance), and the reading start signal for the document is not detected before the document reaches the reading position. The original is stopped upstream of the reading position, and when the signal is detected, the original is not stopped upstream of the reading position and is continuously conveyed to the reading position, thereby preventing a conveyance loss (registration loss) due to the temporary stop. Techniques for reducing are disclosed. However, since the preceding document is being read, the roller immediately before the reading position cannot be stopped, and in order to perform skew correction butting control, the trailing edge of the preceding document passes through the reading position. Control to stop the reading drive and bring the leading edge of the next original against the roller is essential. However, this causes a problem that the distance between the originals is widened and the productivity does not increase as expected.
In addition, in the mode in which reading is continuously performed without temporarily stopping the original in order to increase productivity, the interval between the originals is reduced and the productivity is improved, but the skew correction of the butting cannot be performed, and the image quality is not improved. There is a problem.
Although there is a purpose of making a difference between the speed of the document to be fed and the speed of the receiving roller and making a document deflection by the speed difference to correct the skew, there is a problem that a large correction effect cannot actually be obtained.

Conventionally, as a means for improving the productivity of a method of reading an image while the document is being transported to a reading position, the feeding operation of the next document is started at a timing at which the trailing edge of the document being read does not collide with the leading edge of the next document. Has been aiming to improve productivity by reducing the document spacing.
In addition, an ADF provided with a skew correction mechanism that aligns the front end of the original with the roller stopped immediately after separating the bundle of documents set on the original table into one sheet is common.
However, in the conventional type (Patent Document 1) that temporarily stops at the registration position and waits for a reading start signal from the main body to start reading, the respective transport rollers before and after the reading position are driven by the same driving route. Therefore, it is necessary to stop the reading drive system after completion of reading to the trailing edge position of the preceding document and stop registration of the next document.
In addition, a document whose skew has been corrected immediately after separation may be in a skewed state again when the leading edge reaches the reading position due to roller pressure balance during subsequent conveyance. In addition, it has been verified that the skew correction effect is higher when the front end of the document is abutted.
An unpublished application specification by the present applicant describes an ADF in which the roller drive immediately before reading is a separate drive. However, there is a concern about cost increase and machine enlargement by incorporating an independent motor into the machine. Is done.
There are various types of document feeders for conveying a read document in an image forming apparatus such as a copying machine, a printer, and a facsimile. Conventionally, means for increasing the productivity of a method of reading an image while conveying a reading position As a result, at the timing when the trailing edge of the document being read does not collide with the leading edge of the next document, the feeding operation of the next document is started and the distance between the documents is reduced by feeding it into the machine, aiming to improve productivity.
JP 2002-2984 A JP 2001-160887 A JP 2002-120956 A

However, in order to improve the image quality, the reading drive is stopped when the trailing edge of the preceding original leaves the reading position, and the next original separated and fed at the same time as the stop is stopped upstream of the reading position. The operation of hitting and stopping the roller is required. At this time, the document passing interval indicating whether the productivity is good or not is opened by a distance between the roller upstream of the reading position and the conveyance position of the reading position, and the productivity is lowered as compared with the conventional case.
In the technique described in Patent Document 2, reading is performed without stopping the resist. With this method, productivity can be improved to the utmost limit, but image quality is degraded because skew correction cannot be performed. In addition, in order to perform the reading operation without stopping at the registration position, it is necessary to perform control such that the reading start signal is held first, and if there is a holding request, the reading is performed as it is, and control is complicated. Occurrence of problems due to. For a document to be read, it is easier to manage and there is no problem if a reading start request is issued only to the document while the registration is stopped.
Accordingly, an object of the present invention is to provide a transmission control member such as a clutch in the drive system upstream of the reading drive system (reading upstream (inlet) conveying roller and reading downstream (exiting) conveying roller) in consideration of the above situation. With this configuration, the leading edge of the document can be abutted against the stopped roller just before scanning without waiting for the reading position of the preceding scanned document to pass, improving skew quality and productivity, and increasing the size of the machine. -To provide an ADF that reduces costs.

In order to solve the above-described problems, the invention according to claim 1 is an ADF of a system that reads an image while a sheet document is conveyed along a reading unit, and is a conveyance roller disposed immediately before the reading unit. A reading motor for driving the pair of conveying rollers, a control unit, and a sheet feeding motor for driving a sheet feeding unit that conveys the document toward the pair of conveying rollers. A transmission control member capable of ON / OFF control of transmission of driving force to the conveyance roller pair is provided, and the control unit transmits the transmission when the trailing edge of the preceding document being read by the reading unit passes the conveyance roller pair. The control member is turned off to stop the conveying roller pair, and then the paper feeding motor is driven to abut the leading edge of the next document on the stopped conveying roller pair to correct the skew of the next document. And wherein the door.
According to a second aspect of the present invention, in the first aspect, the control unit turns on the transmission control member when the trailing edge of the preceding original passes through the reading unit, and conveys the next original after the skew correction is completed. It is characterized by starting.
According to a third aspect of the present invention, in the first aspect, the control unit immediately turns on the transmission control member immediately after the leading edge of the next original is abutted against the pair of conveying rollers in a stopped state and the skew correction is completed. Then, the conveyance of the next original is started by the conveyance roller pair.
According to a fourth aspect of the present invention, in the first aspect, the control unit measures the amount of movement of the preceding document and conveys a predetermined time and distance, and then turns on the transmission control member to drive the pair of conveyance rollers. In the transmission state, the next original is conveyed.
According to a fifth aspect of the present invention, the transmission control member according to any one of the first to fourth aspects, wherein the transmission control member prohibits drive transmission according to an energized state of the transmission control member and realizes drive transmission in a non-energized state. A control member is used.
A sixth aspect of the invention is characterized by comprising the ADF according to any one of the first to fifth aspects.

According to the present invention, the drive roller near the reading position upstream is provided with a drive transmission control member such as a clutch, so that only the driving roller (conveying roller pair) near the reading position is read while reading the document. The rotation can be stopped, and the leading edge of the next original is brought into contact with the roller whose rotation has been stopped so that the leading edge is aligned and the skew can be corrected.
Also, by controlling the re-transmission timing of the transmission control member, the document distance between the leading edge of the next document and the trailing edge of the preceding document is reduced, and as a result, the reading interval is shortened, so that productivity can be improved. It becomes possible.
Furthermore, it is possible to provide an ADF that can improve image quality (skew quality) and productivity at the same time, without requiring an increase in the size of the machine and minimizing the cost increase.
According to the present invention, the same performance can be established by using a transmission control member such as a clutch in the current gear portion, and there is an advantage that the size of the machine is not increased and the cost is not significantly increased.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The present embodiment relates to a read original processing apparatus, that is, an ADF, which is used in a sheet-through type reading apparatus that reads an image while conveying the read original to a fixed reading unit and conveying it at a predetermined speed. It is.
FIG. 1 is a schematic sectional view showing the basic configuration of the ADF of the present invention. FIG. 2 is a block diagram of the electrical equipment (control circuit configuration) of the ADF of the present invention. FIG. 3 is a schematic diagram illustrating a first position of two originals when a double-side original fed in the ADF is used.
FIG. 4 is a schematic diagram for explaining a second position of two originals fed in the ADF. FIG. 5 is a schematic diagram for explaining a third position of two documents fed in the ADF. FIG. 6 is a schematic diagram for explaining a fourth position of two documents fed in the ADF.
FIG. 7 is a schematic diagram for explaining the fifth position of two documents fed in the ADF. FIG. 8 is a schematic diagram for explaining the sixth position of two originals fed in the ADF. FIG. 9 is a schematic diagram for explaining the seventh position of two documents fed in the ADF. FIG. 10 is a schematic diagram for explaining the eighth position of two documents fed in the ADF. FIG. 11 is a schematic diagram for explaining the ninth position of two documents fed in the ADF. FIG. 12 is a schematic perspective view illustrating an ADF paper feed drive system according to the present invention.

The present invention will be described with reference to FIGS. The ADF according to the present embodiment can be broadly divided into a document setting unit A for setting a document bundle to be read and a separation for separating and feeding documents one by one from a double-sided document bundle set on the document setting unit A. A feeding unit B, a registration unit C having a function of primarily abutting and aligning the surface of a fed document, and a function of pulling out and transporting the document after alignment, and a document to be conveyed are turned to turn the document surface Turn part D for conveying the image toward the reading side (downward), a reading conveyance part E for reading the original image from below the slit glass 36, and a switchback part F for inverting the front and back of the original after reading. And an intermediate conveyance section G for returning the document switched back by the switchback section F back to the C section.
Further, a switchback unit H for waiting for a temporary document after the document having been read on the front surface is conveyed again from the turn unit D to the reading and conveying unit E without being discharged and the back side of the document is read. A reverse discharge unit I that reverses the original from the unit H and discharges it outside the apparatus, a stack unit J that stacks and holds the originals after reading, driving units 37, 38, and 40 to 43 that drive these conveying operations, And a controller unit 39 for controlling a series of operations.
The original bundle 1 to be read is set on the original table 2 including the movable original table 3 with the original surface facing upward. Further, the width direction of the document bundle 1 is positioned in a direction orthogonal to the conveyance direction by a side guide (not shown).
The setting of the document is detected by the set filler 4 and the set sensor 5 and transmitted to the main body control unit 49 by the I / F. Further, the document length detection sensor S (a reflective sensor or an actuator type sensor that can detect even one document) is provided on the surface of the document table 2 to determine the approximate length of the document in the conveyance direction. (At least a sensor arrangement that can determine whether the document size is vertical or horizontal is necessary).
The movable document table 3 is configured to be moved up and down in the a and b directions shown in FIG. 1 by a bottom plate raising motor 35 (not shown). When the set filler 4 and the set sensor 5 detect that the document is set, the bottom plate is raised. The motor 35 is rotated forward to raise the movable document table 3 so that the uppermost surface of the document bundle contacts the pickup roller 7.

The pickup roller 7 is operated by a pickup motor 38 in the c and d directions shown in the figure by the cam mechanism, and the movable table 3 is lifted and pushed by the upper surface of the document on the movable table 3 to rise in the c direction. 8, the upper limit can be detected.
When a print key (not shown) is pressed from the main body operation unit 50 and a document feed signal is transmitted from the main body control unit 49 to the ADF controller 39 via the I / F, the pickup roller 7 is fed as shown in FIG. The roller is driven to rotate by the forward rotation of the paper motor 40, and several (ideally, one) originals on the original table 2 are picked up.
The rotation direction is a direction in which the uppermost document is conveyed to the sheet feeding port. The paper feeding belt 9 is driven in the paper feeding direction by the normal rotation of the paper feeding motor 40, and the reverse roller 10 is driven to rotate in the reverse direction to the paper feeding by the normal rotation of the paper feeding motor 40, and the uppermost document and the document under it. Are separated, and only the uppermost document can be fed.
More specifically, the reverse roller 10 is in contact with the paper feed belt 9 at a predetermined pressure, and when the paper is in direct contact with the paper feed belt 9 or through one original, the reverse roller 10 is rotated. Thus, the anti-clockwise rotation is set so that when the original enters between the sheet feeding belt 9 and the reverse roller 10 by two or more sheets, the accompanying force is lower than the torque of the torque limiter.
The reverse roller 10 rotates in the clockwise direction, which is the original driving direction, and pushes back an excess original, thereby preventing double feeding. The original separated by the action of the paper feed belt 9 and the reverse roller 10 is further fed by the paper feed belt 9, and the leading edge is detected by the abutment sensor 11.
Further, it comes into contact with the pull-out roller 12 that has stopped. After that, a predetermined amount of distance is sent from the detection of the abutting sensor 11, and as a result, the paper feed motor 102 is stopped while being pressed against the pull-out roller 12 with a predetermined amount of deflection. The drive of the paper feed belt 9 is stopped.
At this time, by rotating the pickup motor 38, the pickup roller 12 is retracted from the upper surface of the document, and the document is fed only by the conveying force of the paper feed belt 9, so that the leading edge of the document enters the nip of the upper and lower rollers of the pull-out roller 12. The tip is aligned (skew correction).

The pull-out roller 12 has the skew correction function and is a roller for conveying the skew-corrected document after separation to the turn roller 14 and is driven by the reverse rotation of the paper feed motor 40.
At this time (at the time of reverse rotation of the paper feed motor 40), the pull-out roller 12 and the turn roller 14 are driven, but the pickup roller 7 and the paper feed belt 9 are not driven.
A plurality of document width sensors 13 are arranged in the depth direction and detect the size in the width direction orthogonal to the transport direction of the document transported by the pull-out roller 12.
The length of the document in the conveyance direction is determined by the control unit from the motor pulse by reading the leading edge and the trailing edge of the passing document with the butting sensor 11. When the document is transported from the resist section C to the turn section D by driving the pull-out roller 12 and the turn roller 14, the transport speed at the resist section C is set higher than the transport speed at the read transport section E. Thus, the processing time for sending the document to the reading unit is shortened.
When the leading edge of the document is detected by the reading entrance sensor 15, the speed is reduced so that the document feeding speed is the same as the reading and feeding speed before the leading edge of the document enters the nip between the upper and lower roller pairs of the reading inlet roller (pair of conveying rollers) 16. At the same time, the reading motor 41 is driven forward to drive the reading inlet roller 16, the reading roller 19, and the reading outlet roller 21. The reading motor 41 is turned on and off to transmit a driving force output by a clutch as a transmission control member described later.
When the leading edge of the document is detected by the registration sensor 17, the effective image area in the sub-scanning direction of the image surface with respect to the main body control unit 49 at the timing when the leading edge of the document detected by the pulse count of the reading motor 41 reaches the reading unit 48. Is transmitted through the reading unit 48 until the trailing edge of the original comes off.
In the case of single-sided document reading, the lower reversing switching claw 23 and the double-sided switching claw 30 are at positions indicated by solid lines, and the document that has passed through the reading conveyance unit E is conveyed to the paper discharge unit J. At this time, when the paper discharge sensor 22 detects the leading edge of the original, the paper discharge motor 42 is driven to rotate forward to rotate the paper discharge roller 28 counterclockwise (paper discharge direction).
Further, the drive speed of the discharge motor 42 is reduced immediately before the trailing edge of the document comes out of the nip between the upper and lower roller pairs of the discharge roller 28 by the pulse count of the discharge motor 42 from the detection of the trailing edge of the document by the discharge sensor 22. Thus, control is performed so that the document discharged onto the discharge tray 29 does not jump out.

Here, the advance operation of the next original when reading one-side original will be described. When the abutment sensor 11 detects the passage of the trailing edge of the preceding document, the feeding motor 40 is temporarily stopped at the timing when the trailing edge of the document has pulled out of the pull-out roller 12 by the pulse count of the feeding motor 40 and rotated in the forward direction again. To drive. By this operation, the feeding operation of the next original is started.
At this time, transmission of the driving force to the turn roller 14 is stopped, but since the timing pulley 63 integrated coaxially with the shaft of the turn roller 14 has a built-in one-way clutch, the turn roller 14 is continuously connected. It is designed to turn around. The next document fed is waiting in a state of being abutted against the pull-out roller 12.
When the preceding document reaches a position (a position near the reading entrance roller 16 determined by the pulse count after the trailing edge of the document passes through the reading entrance sensor 15), the sheet feeding motor 40 is driven in reverse to perform the next. The document is conveyed from the pull-out roller 12.
Next, the case of reading a double-sided document will be described. The process up to the reading of the first side (front side) of the original is the same as described above, but the advance operation is not performed during the reading operation of the first side, and the next original is on the original table 2.
When the leading edge of the document passes the registration sensor 17, the double-side switching claw 30 moves in the i → j direction by turning on the double-side switching claw SOL46 (FIG. 2). The first surface of the original is read by the reading unit 48 of the reading and conveying unit E, and is guided from the lower reversing switching claw 23 to the upper switchback reversing unit F through the paper discharge roller 28 and the upper part of the both-side switching claw 30 (FIG. 5). .
When the leading edge of the document passes through the paper discharge sensor 22, the paper discharge motor 42 is driven to rotate forward, and the paper discharge roller 28 is rotated counterclockwise. At the same time, the upper reverse motor 37 is driven to rotate forward. The reverse roller 31 is also rotated counterclockwise.
When the paper discharge sensor 22 detects the trailing edge of the document, the paper discharge motor 42 and the upper reverse motor 37 are increased so as to be faster than the reading conveyance speed, and the reading motor 41 stops.
Further, after the paper discharge sensor 22 detects the trailing edge of the document, the double-side switching claw 30 turns off the double-side switching claw SOL 46 at the timing when the trailing edge of the document exits the paper discharge roller 28 by the pulse count of the paper discharge motor 42 ( FIG. 1) Return to j → i direction.

Next, when the upper reversing sensor 32 detects the trailing edge of the document, the upper reversing motor 37 is switched from the normal rotation driving to the reverse rotation driving, so that the upper reversing roller 31 changes the rotation direction from the counterclockwise direction to the clockwise direction, thereby causing the document A switchback operation is started (FIG. 6).
By rotating the paper feed motor 40 in reverse at this timing, the relay roller 33, the pull-out roller 12, and the turn roller 14 rotate in the feed direction. The document is sent again to the registration unit C and the turn unit D through the intermediate conveyance unit G.
When the reading entrance sensor 15 detects the leading edge of the document, the sheet feeding motor 40 is temporarily stopped by being abutted against the reading entrance roller 16 stopped with a predetermined deflection by the pulse count of the sheet feeding motor 40. Thereby, alignment (skew correction) of the leading edge at the time of reading the second side of the document is performed (FIG. 7).
By again driving the paper feed motor 40 in the reverse direction and driving the reading motor 41 in the normal direction, the original is fed into the reading conveyance section E. When the registration sensor 17 detects the leading edge of the original, the lower inversion switching claw 23 is switched in the lower inversion. When the claw SOL44 is turned on, it moves in the e → f direction (FIG. 1).
Next, reading of the second surface of the document is started by the reading unit 48 (fixed scanner), and when the paper discharge sensor 22 detects the leading edge of the document, the lower reversing motor 43 is driven forward. As a result, the lower reverse roller 25 rotates counterclockwise, and the document passes through the lower portion of the lower reverse switching claw 23 and is guided to the switchback portion H (FIG. 8).
When the paper discharge sensor 22 detects the trailing edge of the document whose second surface has been read, the lower inversion switching claw SOL44 is turned off by the pulse count of the lower inversion motor 43 (FIG. 1). → Return to e. At the same time, the lower reverse motor 43 is stopped, whereby the rear end of the document is held by the lower reverse roller 25 and enters a standby state (FIG. 8).

Here, the first-out operation at the time of duplex reading will be described. When the original whose first surface has been read is conveyed from the switchback F to the intermediate conveying portion G, the upper reversing sensor 32 detects the trailing edge of the preceding original. Then, the feeding of the next original is started by switching the rotation direction of the paper feeding motor 40 from the reverse driving to the normal rotation at the timing when the trailing edge of the original passes through the pull-out roller 12 by the pulse count of the paper feeding motor 40.
Thereafter, the operation is performed at the same timing (between sheets) as in the case of single-sided reading. The next original is aligned at the leading edge by the pull-out roller 12 of the registration unit C (FIG. 8), and is sent to the reading conveyance unit E from the turn unit D.
When the registration sensor 17 detects the leading edge of the next original, the double-side switching claw 30 moves from i to j in FIG. 1, and the reading exit roller 21 and the reverse lower switching claw 23 are read while the first unit is being read by the reading unit 48. Is passed to the switchback portion F through the paper discharge roller 28 and the upper part of the double-side switching claw 30, and the double-side switching claw 30 returns to j → i (FIGS. 9 and 10).
The next original is then read on the second side in the same process as described above. By operating in this way, the reading of the first and second sides is completed, and the next original overtakes the original in the standby state at the switchback portion H.

By turning on the lower inversion switching claw SOL45 at the timing when the double-side switching claw 30 returns from j to i, the lower inversion switching claw 24 is moved from g to h. Further, by driving the lower reversing motor 43 in the reverse direction, the lower reversing roller 25 and the auxiliary roller 27 rotate in the clockwise direction so that the original is conveyed from the reversing discharge unit I to the stack unit J.
By turning off the lower inversion switching claw SOL45 at the timing when the leading edge of the document is added to the ejection roller 28 by the pulse count of the lower inversion motor 43, the lower inversion ejection switching claw 24 is returned from h → g.
The auxiliary roller 27 is installed in order to reduce the load caused by winding the document around the inner guide plate. Next, when the lower reverse sensor 26 detects the trailing edge of the document, it is discharged immediately before the trailing edge of the document leaves the nip between the pair of upper and lower rollers of the discharge roller 28 by the pulse count of the discharge motor 42 as in the case of single-sided discharge. Control is performed such that the driving speed of the motor 42 is reduced and the document discharged onto the discharge tray 29 does not jump out (FIG. 11). The operation is completed by repeating the above operation for a predetermined number of documents.
FIG. 12 is a schematic perspective view for explaining an ADF drive system according to the present invention. FIG. 13 is a timing chart for explaining drive timing in the ADF according to the present invention.
FIG. 14 is a timing chart showing the timing of starting the conveyance of the next original, together with the relationship between the reading entrance roller, the registration sensor, and the reading position, when the preceding original passes through the reading position (gate off).

One feature of this embodiment is an ADF that reads an image while conveying a sheet document along a reading unit 48 (reading position), and includes a pair of conveying rollers 16 disposed immediately before the reading unit 48, A reading motor including a reading motor 41 for driving a pair of conveying rollers, a control unit 49, and a sheet feeding motor 40 for driving sheet feeding means 12 and 14 for conveying a document toward the pair of conveying rollers 16. A transmission control member 47 capable of ON / OFF control of transmission of driving force from the roller 41 to the conveying roller pair 16 is provided, and the control unit 49 transmits the trailing edge of the preceding document being read by the reading unit when it passes through the conveying roller pair. The control member 47 is turned off to stop the conveying roller pair 16, and then the paper feeding motor 40 is driven to abut the leading edge of the next document against the stopped conveying roller pair. There is a configuration in which to perform the positive.
That is, in timing A in FIG. 14, at the timing when the preceding document D1 has passed the registration sensor 17, the clutch 47 is turned off and transmission of the driving force from the reading motor 41 is turned off to drive the reading entrance roller 16. Prohibit transmission. At the same time (or after the stop) as the reading entrance roller 16 stops rotating, the paper feed motor 40 is driven in the counterclockwise direction, and the next original D2 is carried in at the timing of stoppage. Reading the preceding document D1 is continued as it is.
At timing B, when the trailing edge of the preceding document D1 leaves the reading position, the clutch (transmission control member) 47 is turned on to transmit the driving force of the reading motor 41, thereby restarting the driving transmission of the reading inlet roller 16. . The next original D2 is conveyed to a predetermined registration stop position, and registration is stopped. The interval between sheets is equivalent to the condition of timing A. At timing C, reading is started by a reading start signal.
FIG. 15 is a timing chart showing the conveyance start timing of the next document together with the relationship between the reading entrance roller, the registration sensor, and the reading position after confirming the stop of the paper feed motor due to the abutting / alignment of the next document.
In FIG. 15, at the timing A, when the trailing end of the preceding document D <b> 1 passes the registration sensor 17, the clutch 47 is turned off and the drive transmission from the reading motor 41 to the reading entrance roller 16 is prohibited. Simultaneously with the stop of the rotation of the reading entrance roller 16 (or immediately after the stop), the paper feed motor 40 is driven to carry in the next original D2 at the timing of the stoppage. The preceding document D1 continues to be read as it is.
At timing B, after the abutting operation is completed, the clutch is immediately turned on, and the drive transmission from the reading motor 41 to the reading entrance roller 16 is resumed. Control is performed such that the gap between the trailing edge of the preceding document D1 that has passed the reading position and the predetermined registration stop position is the minimum sheet interval. At timing C, reading is started by a reading start signal.

FIG. 16 is a schematic perspective view showing a configuration in which an electromagnetic clutch for controlling drive transmission is provided to the reading entrance roller.
12 and 13, the reading entrance roller 16 is included in the separation / pull-out drive system as shown in FIG. 12, and is driven separately from the read drive system. First, the ADF paper feed drive system will be described.
First, an ADF drive system will be described. When the paper feed motor 40 rotates at the time of separation indicated by a solid line arrow, this drive is transmitted to the pulley 51 → the pulley 52 → the gear 55 → the gear 56. The drive transmitted from the gear 56 to the gear 57 rotates the paper feed belt 9, and the drive transmitted from the gear 58 → the gear 59 → the gear / pulley 60 → the pulley 61 rotates the pickup roller 7.
Further, the drive transmitted from the gear 56 to the gear 64 rotates the reverse roller 10. At this time, the drive is not transmitted to the gear / pulley 53 coaxial with the gear 55 and the gear 54 coaxial with the gear 64 by the action of the one-way clutch.
Further, when the paper feed motor 40 rotates during paper feed indicated by a broken line arrow, this drive is transmitted to the pulley 51 → the pulley 52 → the gear / pulley 53. The drive transmitted from the gear / pulley 53 to the gear 54 rotates the reverse roller 10.
Further, the drive transmitted from the gear / pulley 53 → the pulley 62 → the pulley 63 and the pulley 62 → the pulley 65 → the pulley 66 rotates the pull-out roller 12, the turn roller 14, and the relay roller 33. At this time, the drive is not transmitted to the gear 55 and the gear 54 coaxial with the gear / pulley 53 by the action of the one-way clutch.

A first embodiment of the present invention will be described with reference to FIG. 1, FIG. 2, FIG. 13 and FIG. In the present invention, as shown in FIG. 16, an electromagnetic clutch 47 for controlling transmission of driving force to the reading entrance roller 16 is provided, and is connected so that the controller 39 can control on / off thereof. ing. The electromagnetic clutch 47 is configured such that transmission is cut off in the off state (non-energized state), and driving is not transmitted to the reading entrance roller 16.
The timing will be described with reference to FIG. In order to divide the bundle of documents set on the document table into one and align the leading end with the pull-out roller 12, the sheet feeding motor is temporarily stopped.
The document whose abutting skew has been corrected is conveyed to the reading unit by the pull-out roller 12 in a state where only the separation driving is stopped by the reverse of the paper feeding motor. It is not necessary to drive the reading motor for the first sheet because there is no preceding document, but the reading speed is adjusted when the first sheet is conveyed to the vicinity of the reading entrance roller 16 for the same control as the second and subsequent documents. Drive.
Further, when the first sheet is fed, the detection of the off edge of the registration sensor 17 is not detected. Therefore, the clutch 47 remains in the off state, and the reading entrance roller 16 is not rotated even when the reading motor 41 is driven. The exit rollers 21 rotate at the same speed.
Based on the conveyance distance from the pull-out roller 12, the amount of abutting conveyance to the reading entrance roller 16 in a stopped state is controlled, and once stopped and aligned with the leading end of the document in contact with the reading entrance roller 16, When the tip alignment is completed, the clutch 47 is brought into a connected state, whereby the drive is transmitted to the reading entrance roller 16 and rotation / conveyance is started.
When the transmission of the clutch 47 is started (ON), the pull-out roller 12 is driven to assist, and the load due to the document slip is reduced. After conveying a predetermined amount from the reading entrance roller 16, a registration stop signal is sent to the main body control unit 49 (FIG. 2). From this point, reading of the first sheet is started and separation of the next original is performed while the reading is being executed, the conveyance amount of the trailing edge of the preceding original is monitored, and conveyance of the next original toward the reading unit is started.
If the registration sensor 17 can detect the trailing edge of the document being read, the reading entrance roller 16 has been removed. Therefore, the controller 39 changes the clutch 47 to the OFF state and makes the reading entrance roller 16 non-rotating.
When the next original is conveyed so that the next original stops while the rotation of the reading entrance roller 16 stops, the efficiency (productivity) becomes the highest. When the driving of the paper feed motor 40 is stopped and the leading edge of the document against the reading entrance roller 16 is completed, the driving of the reading entrance roller 16 is transmitted and rotation / conveyance is started by connecting the clutch 47.

FIG. 17 is a schematic perspective view for explaining a reading and conveying drive system. FIG. 18 is a schematic perspective view illustrating the lower inversion unit driving system. FIG. 19 is a schematic perspective view illustrating the paper discharge drive system. FIG. 20 is a schematic perspective view illustrating the upper inversion unit drive system.
In FIG. 17, when the reading motor 41 rotates, it is transmitted from the pulley 67 to the pulley 68. The driving force transmitted from the pulley 68 to the pulley 69 and the pulley 70 rotates the reading outlet roller 21 and the reading inlet roller 16, respectively, and the driving force transmitted from the pulley 69 to the pulley 78 rotates the reading roller 19.
In FIG. 18, when the lower reversing motor 43 rotates, it is transmitted to the pulley 73 → the pulley 74 → the pulley 75 to rotate the lower reversing roller 25 and the auxiliary roller 27. In FIG. 19, when the paper discharge motor 42 rotates, it is transmitted from the pulley 71 to the pulley 72, and the paper discharge roller 28 is rotated.
In FIG. 20, when the upper reversing motor 37 rotates, it is transmitted from the pulley 76 to the pulley 77 to rotate the upper reversing roller 31.
In the present invention, as shown in FIG. 14, the next document conveyance start timing is set when the preceding document has passed the reading position (gate off), and the next document whose leading end is abutted and aligned by reconnecting the clutch 47 is brought into the conveyance state. The document is stopped at the registration stop position.
In another embodiment of the present invention, as shown in FIG. 15, the next document conveyance start timing is confirmed by immediately reconnecting the clutch 47 after confirming the stop of the paper feed motor 40 due to the abutting / alignment of the next document. Then, the next original that has been abutted and aligned is brought into a conveyance state, and the original is stopped at a predetermined registration stop position.

Further, the present invention will be described with reference to FIGS. 1 and 13. The controller 39 starts counting the number of pulses applied by the reading motor 41 from the time when the registration sensor 17 detects the trailing edge of the preceding reading document, and the predetermined conveying amount. After confirming that the sheet has been conveyed, the clutch 47 is brought into a connected state so that the distance between the preceding document and the leading edge of the next document is adjusted. A device in which the logic of the clutch 47 is reversed can also be set.
In the ADF of the present invention, in the control of a drive transmission control member such as the clutch 47 provided in the driving roller near the upstream of the reading position, the roller 16 whose trailing edge of the preceding document being read is near the upstream of the reading position. Propagation is prohibited when exiting.
As a result, the rotation of the roller 16 stops, and at the timing when the rotation stops, the leading edge of the next document is abutted against the stopped roller 16 and aligned with the leading edge, thereby correcting the skew of the next document.
Further, in order to prevent vibration caused by permitting drive transmission from affecting the original being read and blurring of the image, control is performed so that drive transmission is performed after the preceding original has been read.
To provide an ADF that satisfies both high productivity and image quality because the distance between the originals can be narrowed (reduced) rather than the leading end of the next original abutting and stopping after passing through and stopping the reading position of the preceding original. Can do.

In the ADF of the present invention, in the control of a drive transmission control member such as a clutch provided in the drive roller in the vicinity of the upstream of the reading position, the roller 16 in which the trailing edge of the preceding document being read is in the vicinity of the upstream of the reading position. The rotation of the roller 16 is stopped by prohibiting transmission at the time of passing through the position, and at the timing when the rotation stops, the leading edge of the next document is abutted against the stopped roller 16 and the leading edge is aligned, thereby correcting the skew of the next document. .
Further, if the drive system is configured such that the vibration caused by permitting drive transmission does not significantly affect the document being read, it is possible to reduce the distance between the documents most. It is possible to provide an ADF that satisfies both high productivity and image quality.
In the ADF of the present invention, in the control of a drive transmission control member such as a clutch provided in the drive roller in the vicinity of the upstream of the reading position, the roller 16 in which the trailing edge of the preceding document being read is in the vicinity of the upstream of the reading position. The rotation of the roller 16 is stopped by prohibiting transmission when it passes through the position, and at the timing when the rotation stops, the leading edge of the next document is abutted against the stopped roller 16 and the leading edge is aligned, thereby correcting the skew of the next document. .
By measuring the carry amount pulse from the registration sensor, the trailing edge position of the preceding document can be grasped, and the conveyance start timing of the next document is controlled according to the advance amount. This makes it possible to provide an ADF satisfying both high productivity and image quality, which enables finer control between papers and makes adjustments according to the specifications even when mounted on different main bodies. .
In the ADF according to the present invention, the electromagnetic clutch is energized only when it is desired to stop the reading entrance roller by selecting a device that is disconnected only when the electromagnetic clutch is energized and does not transmit the drive transmission. be able to. As a result, it is possible to design without the need to consider the heat dissipation due to the reduction of power consumption and temperature rise, and it is possible to provide a higher quality ADF.

1 is a schematic sectional view showing a basic configuration of an ADF of the present invention. The electrical equipment block diagram of ADF of this invention. FIG. 3 is a schematic diagram illustrating a first position of two originals when a double-side original fed in an ADF is used. FIG. 6 is a schematic diagram illustrating a second position of two documents fed in an ADF. FIG. 6 is a schematic diagram illustrating a third position of two documents fed in an ADF. FIG. 10 is a schematic diagram illustrating a fourth position of two documents fed in the ADF. FIG. 10 is a schematic diagram illustrating a fifth position of two documents fed in an ADF. FIG. 10 is a schematic diagram illustrating a sixth position of two documents fed in the ADF. FIG. 10 is a schematic diagram for explaining a seventh position of two documents fed in an ADF. FIG. 10 is a schematic diagram illustrating an eighth position of two documents fed in the ADF. FIG. 10 is a schematic diagram for explaining a ninth position of two documents fed in the ADF. The schematic perspective view explaining the paper feed drive system of ADF by the present invention. 4 is a timing chart illustrating driving timing in the ADF according to the present invention. 6 is a timing chart when the next document conveyance start timing is when the preceding document passes through the reading position (gate off). FIG. 6 is a timing chart when the next document conveyance start timing is confirmed after the stop of the paper feed motor due to the abutting / alignment of the next document. FIG. 3 is a schematic perspective view showing a configuration in which an electromagnetic clutch for controlling drive transmission is provided to a reading entrance roller. The schematic perspective view explaining a reading conveyance drive system. The schematic perspective view explaining a lower inversion part drive system. FIG. 2 is a schematic perspective view illustrating a paper discharge drive system. The schematic perspective view explaining an upper inversion part drive system.

Explanation of symbols

A Document setting section, B Separating section, E Reading and conveying section, 7 Pickup roller, 9 Feeding belt (separation mechanism), 12 Pull-out roller, 16 Conveying roller pair (reading entrance roller), 21 Reading exit roller, 40 Feeding motor , 41 Reading motor, 47 Transmission control member (clutch) capable of controlling drive transmission, 48 Reading section

Claims (6)

An automatic document feeder of a type that reads an image while conveying a sheet document along a reading unit, a conveying roller pair disposed immediately before the reading unit, a reading motor that drives the conveying roller pair, A controller, and a paper feed motor that drives a paper feed means for transporting the document toward a pair of transport rollers,
A transmission control member capable of on / off control of transmission of driving force from the reading motor to the conveying roller pair;
The control unit turns off the transmission control member to stop the conveyance roller pair when the trailing edge of the preceding document being read by the reading unit passes the conveyance roller pair, and then turns the sheet feeding motor An automatic document feeder which corrects the skew of the next document by abutting the leading edge of the next document against the pair of conveying rollers which are driven and stopped.   The control unit turns on the transmission control member when the trailing edge of the preceding document passes through the reading unit, and starts conveying the next document after skew correction is completed. Automatic document feeder.   The controller immediately turns on the transmission control member immediately after the leading edge of the next document is abutted against the pair of transport rollers in a stopped state and the skew correction is completed, and the transport of the next document by the transport roller pair is started. The automatic document feeder according to claim 1, wherein:   The controller measures the amount of movement of the preceding document and conveys it for a predetermined time and distance, and then turns on the transmission control member to bring the driving of the pair of conveyance rollers into a transmission state and conveys the next document. The automatic document feeder according to claim 1.   5. The transmission control member that prohibits drive transmission according to an energized state to the transmission control member and uses the transmission control member to realize drive transmission in a non-energized state is used as the transmission control member. Automatic document feeder according to the item. An image forming apparatus comprising the automatic document feeder according to claim 1.

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