JP2006188338A - Automatic document feeder and image forming device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an automatic document feeder capable of performing the resist stop without waiting for a preceding original to be read passing through the reading position by separately driving a reading upstream (inlet) conveying roller from a reading downstream (outlet) conveying roller, and enhancing both the productivity and the image quality by performing the skew correction by a roller immediately before the reading without expanding the spacing between the original sheets since the stopped state is also used for the butting action to perform the skew correction. <P>SOLUTION: In the automatic document feeder of the type for reading images while conveying sheet originals, conveying roller pairs 16 immediately before the reading position have a drive source 47 separate from the reading and conveying drive. <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 during conveyance of a sheet document, and is particularly equipped with an image forming apparatus such as a copying machine or a facsimile to improve productivity. It can be related to ADF.

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.
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.
In view of the above-described circumstances, an object of the present invention is to make the reading upstream (entrance) conveyance roller different from the reading downstream (exit) conveyance roller without waiting for the reading position of the preceding reading document to pass. The registration can be stopped, and the stopped state also serves as an abutting operation for skew correction, so that the productivity can be improved and the image quality can be improved without increasing the space between the original paper and the skew immediately before reading. It is to provide an ADF that combines both.

In order to solve the above-described problem, the invention according to claim 1 is an ADF that reads an image while a sheet document is conveyed along a reading unit, and is a conveyance roller disposed immediately before the reading position. And a pair of other reading and conveying drive systems, wherein the driving system of the pair of conveying rollers immediately before the reading position is a separate system from the other reading and conveying driving system.
A second aspect of the present invention is characterized in that, in the first aspect, the drive system of the separating and conveying section located upstream of the conveying roller pair is a separate system.
According to a third aspect of the present invention, in the second aspect of the invention, in the state in which the pair of conveyance rollers is stopped, the separation conveyance unit is driven, and the leading end of the conveyed document is abutted against the conveyance roller pair to stop the skew correction. The control part which performs is characterized by the above-mentioned.
According to a fourth aspect of the present invention, in the third aspect, the control unit corrects the skew by abutting the leading end of the document against the pair of transport rollers that has stopped rotating, and the state stopped at that position is defined as a registration stop position. It is characterized by doing.
According to a fifth aspect of the present invention, in the third or fourth aspect, the control unit drives the pair of conveyance rollers and the other reading conveyance driving system at the same time, and the reading unit reads the document. The rotation of the conveying roller pair is stopped when the trailing edge of the document passes through the pair of conveyance rollers, and the skew correction is performed after the leading edge of the next document is abutted against the conveyance roller pair immediately after the rotation is stopped. It is characterized by.
An image forming apparatus according to a sixth aspect of the present invention includes the ADF according to any one of the first to fifth aspects.

According to the present invention, the driving roller in the vicinity of the upstream of the reading position is a driving system different from the reading driving system, and the same as the driving system on the paper feeding side, so that the discharge control without stopping the preceding document being read is performed. In addition, by controlling the pull-out start timing of the next original, the original interval can be shortened to the limit.
Furthermore, since registration is always stopped for each original document, reading can be performed by exchanging signals on a one-to-one basis without an advance reading start signal, so that control problems and skew are less likely to occur. It is possible to provide an ADF characterized by high productivity that can close the space between manuscript sheets while always stopping the registration and simplifying the control.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic view showing an ADF according to the present invention. FIG. 2 is a block diagram showing an ADF control circuit according to the present invention. FIG. 3 is a schematic diagram illustrating a first position of two documents fed in the ADF.
FIG. 4 is a schematic diagram for explaining the second position of two documents 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 for explaining an ADF 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 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 a 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 bundle set in the original setting portion A is separated into one sheet by the action of the paper feeding belt 9 and the reverse roller 10, and further fed by the paper feeding belt 9, and the leading end is detected by the abutting sensor 11, and further It strikes against the pull-out roller 12 that has stopped.
Thereafter, a predetermined distance is sent from the detection of the abutting sensor 11, and as a result, the paper feed motor 40 is stopped while being pressed against the pull-out roller 12 with a predetermined amount of bending. The drive of the paper feed belt 9 is stopped.
At this time, the pickup motor 38 is rotated so that the pickup roller 7 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, whereby the leading edge of the document enters the nip between the upper and lower roller pairs of the pull-out roller 12. Then, tip alignment (skew correction) is performed.
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 to be 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, at the same time as decelerating is started in order to make the document conveyance speed the same as the reading conveyance speed before the document leading edge enters the nip between the upper and lower roller pairs of the reading inlet roller 16, The reading motor 41 is driven to rotate forward to drive the reading inlet roller 16, the reading roller 19, and the reading outlet roller 21.
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, and is sent from the turn unit D to the reading conveyance unit E.
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 surfaces 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.

Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. 1, 12, and 13. FIG. In the present invention, as shown in FIG. 12, the reading entrance roller (conveying roller pair) 16 is incorporated in the separation / pullout drive system, and is driven separately from the other read drive systems.
That is, the present embodiment is an ADF that reads an image while transporting a sheet document along the reading unit 48, and includes a pair of transport rollers 16 disposed immediately before the read unit and other read transport driving systems. The drive system of the transport roller pair 16 immediately before the reading unit is distinct from the other read transport drive system.
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.
In order to drive and rotate the pickup roller 7 in contact with the bundle of documents set on the document table 2, the paper feed motor 40 is rotated forward. In this normal rotation, the pull-out roller 12, the turn roller 14, and the reading entrance roller 16 are not rotated and stopped.

The uppermost paper separated into one sheet by the separation unit B is transported into the machine and the leading edge is detected by the abutting sensor 11 and then stopped with the leading edge abutted against the pull-out roller 12. Here, skew correction of the tip is performed (A in FIG. 13).
After confirming that the abutting motor is stopped, the pull-out roller 12, the turn roller 14, and the reading entrance roller 16 are rotated by rotating the paper feed motor 40 in the reverse direction, and the document is further conveyed into the apparatus. In this reverse rotation, the driving is not transmitted to the separation belt 9 and the rotation is stopped.
The leading end position of the document is detected by the reading entrance sensor 15 and conveyed to a position passing through the reading entrance roller 16 to stop the document. This stop position is the registration stop position (the setting of the abutting amount in B in FIG. 13 is not set), and a state of waiting for a reading start signal from the main body is entered. When the main body is ready for reading and is ready for reading, a reading start signal is issued and the ADF starts reading.
Since the trailing edge of the document is still sandwiched between the pull-out rollers 12, the reading inlet motor 47 (FIG. 2) and the paper feeding motor 40 are simultaneously rotated at the same speed to convey the document to the reading unit (see FIG. 13 C).
When the trailing edge of the original is detected by the abutting sensor 11 and conveyed by a distance that passes through the pull-out roller 12, the paper feed motor 40 is stopped and the operation proceeds to the next original separation operation. The roller pair downstream of the pull-out roller 12 has a weak pressure contact force, so that even when the paper feed motor 40 is stopped, it can be pulled out only by reading driving.
The next original is separated and abutted from here, and the next original is fed. When the reading entrance sensor 15 detects the trailing edge of the document being read (preceding document), it can be determined how long the document can pass through the reading entrance roller 16, so that the next document is pulled out at the timing of exiting the reading position. To start. As a result, the registration of the next original is stopped at the same time as the reading is completed, and the original interval can be set smaller.
As described above, according to the present embodiment, since the registration is stopped, reading can be performed by exchanging a one-to-one signal without preceding the reading start signal. In addition, it is possible to provide an automatic document pause device characterized by high productivity that can close the space between document sheets while always stopping registration and simplifying control.

FIG. 14 is a schematic perspective view showing a conventional separation / pullout drive system. FIG. 15 is a schematic perspective view showing the drive system of the reading motor. FIG. 16 is a schematic perspective view showing a drive system of the reading inlet motor.
A second embodiment of the present invention will be described below with reference to FIGS. 1, 14 (separation / pull-out drive system), FIG. 15 (read drive system), FIG. 16 (read inlet drive system), and FIG. In the present invention, as shown in FIG. 16, the reading inlet roller 16 is driven by another drive source 47, and the reading inlet roller 16 and the reading outlet roller 21 (FIG. 1) are driven separately.
Apart from this, a conventional separation / pull-out drive system is provided as shown in FIG. 14 to separate and convey the original bundle on the original table. The description of the separation / pull-out drive system in FIG. 14 is the same as that in FIG.
In FIG. 14, in order to drive and rotate the pickup roller 7 in contact with the bundle of documents set on the document table 2, the paper feed motor 40 is rotated forward. In the forward rotation, the pull-out roller 12 is not transmitted to the pull-out roller 12 and stops rotating.
The uppermost paper separated into one sheet by the separation unit B is transported into the machine and the leading edge is detected by the abutting sensor 11 and then stopped with the leading edge abutted against the pull-out roller 12. Here, skew correction of the tip is performed (A in FIG. 13).
After confirming that the motor for abutting is stopped, the pull-out roller 12 and the turn roller 14 are rotated by rotating the paper feed motor 40 in the opposite direction, and the document is further conveyed into the apparatus. In this reverse rotation, the driving is not transmitted to the separation belt 9 and the rotation is stopped.
When the leading edge of the document is detected by the reading inlet sensor 15, the leading edge abutting control to the reading inlet roller 16 is entered and the document is stopped. This stop position is the registration stop position (B in FIG. 13), and a reading start signal from the main body is waited. When the main body is ready for reading and ready for reading, a read start signal is issued and the ADF starts reading.

Since both the reading inlet motor 47 in the reading inlet driving system shown in FIG. 16 and the reading motor 41 in the reading driving system shown in FIG. By simultaneously rotating the paper motor 40 at the same speed, the document is conveyed to the reading unit.
When the distance that the trailing edge of the original passes through the pull-out roller 12 is conveyed, the paper feed motor 40 does not need to rotate the pull-out roller 12, so that the operation proceeds to the next original separation operation (C in FIG. 13).
From this point, the next original is separated / abutted / pulled out (D in FIG. 13), and the leading edge of the original is guided to the reading entrance roller 16. Since the preceding document does not need to drive the reading entrance roller 16 when the trailing edge passes through the registration sensor 17, it waits for the leading edge of the next document in a stopped state.
Since the transport speed of the preceding read document and the transport distance from the layout are known, it is possible to know at which point the trailing edge position of the preceding document being read has come to start, and the reading entrance Control is performed so as to start the operation aiming at the timing at which the roller 16 stops rotating.
When the leading edge of the next original reaches the reading entrance roller 16, a second skew correction is performed, and when the registration stop is notified to the main body, a reading start signal is issued from the main body already waiting to read the next original. The ADF immediately transports the document to the reading unit.
In the ADF according to the second embodiment, the discharge roller can be controlled without stopping the document being read by making the drive roller in the vicinity of the upstream of the read position a separate drive system from the read drive system. It becomes.
At the same time, by controlling the pull-out start timing of the next original, the original interval can be shortened to the limit. Further, as described above, since the registration is stopped, reading can be performed by exchanging a one-to-one signal without preceding the reading start signal, so that it is difficult for control problems to occur.
By making the driving roller in the vicinity of the upstream of the reading position completely independent, the driving is stopped when the trailing edge of the document being read through the pull-out roller comes out, and the pulled-out document can be assisted by roller conveyance. Thus, an automatic document pausing device is provided that has high image quality, high image quality, and high productivity that can reduce gaps between manuscript sheets while always stopping registration and simplifying control.

FIG. 17 is a schematic perspective view for explaining the driving of the lower reversing motor. FIG. 18 is a schematic perspective view for explaining the driving of the paper discharge motor. FIG. 19 is a schematic perspective view for explaining the driving of the upper reversing motor.
In FIG. 17, when the lower reversing motor 43 rotates, it is transmitted from the output pulley 73 → the pulley 74 → the pulley 75 to rotate the lower reversing roller 25 and the auxiliary roller 27. In FIG. 18, when the paper discharge motor 42 rotates, the paper is transmitted from the pulley 71 to the pulley 72, and the paper discharge roller 28 is rotated.
In FIG. 19, 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.
According to the present invention, the conveyance roller pair immediately before reading stopped in rotation is stopped by abutting the leading edge of the conveyed document by driving the separating and conveying unit, and performing skew correction. Further, by controlling the pull-out start timing of the next original, the original interval can be shortened to the limit.
In addition, by making the driving roller in the vicinity of the upstream of the reading position completely independent, the roller can be stopped when the trailing edge of the preceding document being read is removed, and the abutting operation can be performed by pull-out conveyance of the next document. Become.
The skew is corrected by abutting the leading edge of the document against the pair of transport rollers immediately before the reading position where the rotation is stopped, and the state stopped at that position is set as a registration stop position. Further, since the registration is stopped, reading can be performed by exchanging a one-to-one signal without preceding the reading start signal, so that it is difficult for control problems to occur.

According to the present invention, when the conveyance roller pair immediately before the reading position and the reading conveyance drive are simultaneously driven and the preceding document is being read, the time when the trailing edge of the document has passed through the conveyance roller pair immediately before the reading position. Then, the rotation of the pair of conveying rollers immediately before the reading position is stopped, and the front end of the next original is abutted and stopped immediately after the stop, and control is performed at the timing of performing skew correction.
As described above, the drive roller near the upstream of the reading position is a separate system from the reading drive system, and a completely independent drive system enables discharge control without stopping the document being read. At the same time, the rear end position of the preceding document is grasped and pull-out conveyance of the next document is started.
As a result, the trailing edge of the document being read through the driving roller in the vicinity of the upstream position of the reading position is pulled out, and the leading edge of the next document is abutted and stopped at the same time when the roller stops, so that the document interval is minimized. Can be shortened. Further, since the registration is stopped, reading can be performed by exchanging a one-to-one signal without preceding the reading start signal, so that it is difficult for control problems to occur.

Schematic which shows ADF concerning this invention. The block diagram which shows the control circuit of ADF concerning this invention. FIG. 3 is a schematic diagram illustrating a first position of two documents fed in an ADF. 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 drive system of ADF by this invention. 4 is a timing chart illustrating driving timing in the ADF according to the present invention. FIG. 10 is a schematic perspective view showing a conventional separation / pull-out drive system. FIG. 3 is a schematic perspective view showing a drive system of a reading motor. The schematic perspective view which shows the drive system of a reading entrance motor. The schematic perspective view explaining the drive of a lower inversion motor. FIG. 3 is a schematic perspective view illustrating driving of a paper discharge motor. The schematic perspective view explaining the drive of an upper reversing motor.

Explanation of symbols

16 Transport roller pair (reading entrance roller)
21 Reading exit roller 40 Paper feed motor 41 Reading motor 47 Another drive source (reading entrance motor)
48 Reading unit

Claims (6)

  An automatic document feeder that reads an image while conveying a sheet document along a reading unit, and includes a pair of conveyance rollers disposed immediately before the reading unit, and another reading conveyance driving system, An automatic document feeder in which a driving system for a pair of conveying rollers immediately before the reading unit is a separate system from the other reading and conveying driving system.   2. The automatic document feeder according to claim 1, wherein the drive system of the separation conveyance unit located upstream of the conveyance roller pair is a separate system.   And a controller that performs skew correction by driving the separation and conveyance unit while stopping the rotation of the conveyance roller pair and stopping the leading edge of the conveyed document against the conveyance roller pair. The automatic document feeder according to claim 2.   The automatic controller according to claim 3, wherein the control unit corrects skew by abutting a leading edge of the document against the pair of conveyance rollers that has stopped rotating, and sets the state stopped at that position as a registration stop position. Document feeder.   The control unit drives the pair of conveyance rollers and the other reading conveyance driving system at the same time, and when the trailing end of the document is removed from the conveyance roller pair while the reading unit is reading the document. 5. The automatic document feeding according to claim 3, wherein the rotation of the conveying roller pair is stopped and skew correction is performed after the leading edge of the next document is abutted against the conveying roller pair immediately after the rotation is stopped. Paper device. An image forming apparatus comprising the automatic document feeder according to claim 1.

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