JP4712849B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus such as a copying machine.

  2. Description of the Related Art Conventionally, in order to allow a copying machine or the like to read both front and back originals of a plurality of originals, first, after reading the first surface (front surface) of the originals with a reading unit, Two sides (back side) are read by the reading unit. In this state, the orientation of the document is opposite to the orientation in which the document was originally placed, and after reading the second surface (back surface), the document is reversed again and passed through the reading unit in order to match the orientation of the document. For this reason, since the document is fed to the reading unit only for aligning the direction of the document, the reading operation cannot be performed during that time, and it takes time to continuously read a plurality of documents, resulting in poor productivity. There was a problem.

  As a method for solving the above-described problem, for example, in Patent Document 1, after reading the first side, the document is switched back twice and fed to the reading unit for reading the second side. A technique is disclosed in which the feeding to the reading unit is completed only twice. However, in this publication, the document cannot be read while being switched back twice and fed again to the reading position. Moreover, until the second page is read and the original is discharged, the next original cannot be fed (cannot be advanced), and as a result, it takes time to produce multiple originals. The problem of getting worse remained. As another conventional technique, Patent Document 2 proposes a configuration in which a reading mechanism is provided exclusively for the second side in order to read both sides at once, and reading is performed without switching back a double-sided document. However, there is a problem that a new separate reading mechanism is required, and the apparatus is increased in size and cost.

JP-A-11-171384 JP-A-9-166936

  The present invention has been made in view of the above points, and provides an image forming apparatus that is capable of reading a double-sided document continuously and efficiently and that can be configured compactly and that is inexpensive and has high productivity. Let it be an issue.

Means for Solving the Problems and Effects of the Invention

In order to solve the above problems, an image forming apparatus of the present invention includes a document placement unit that places a plurality of documents having image information on both sides,
A separation feeding unit that separates and feeds documents one by one from the document placing unit;
A reading conveyance unit that is located downstream of the separation feeding unit and conveys the document to the document reading unit;
A switchback unit that carries in the original after reading the first side of the double-sided document, inverts the second side of the original for reading, and then conveys it to the reading and conveying unit;
An inverted paper discharge unit that carries in the original after double-sided reading, inverts the original to match the orientation placed before reading the original, and then discharges the original.
Including a document feeder having
The switchback unit includes means for temporarily retaining at least one document,
The document reading section reads the document, read and store the page reading order of the document to the page memory section, controlled to form an image by rearranging the image in page order based on the stored page storing unit of the information Forming means to
When the first sensor arranged upstream of the document reading unit detects the first document before reading the first surface, control is performed so as to form a conveyance path from the document reading unit to the switchback unit. First control means;
Second control means for controlling to form a conveyance path from the switchback unit to the reading conveyance unit when the second sensor arranged downstream of the document reading unit detects the trailing edge of the first document. When,
When the third sensor arranged in the switchback unit detects the first document, the switchback operation in the switchback unit is started, and the first surface reading operation and the first sheet of the second document are started. 3rd control means which controls to perform reading operation of the 2nd page of a manuscript in order,
It is provided with.

  With the above configuration, it is possible to feed the next document to the reading position and read the first image surface while the document temporarily stays in the switchback unit. Continuous reading of a plurality of double-sided originals can be performed efficiently.

Further, according to the present invention, as a more preferable aspect, when the number of documents temporarily staying in the switchback portion is a, and then the nth document is fed into the conveyance path (where n ≧ (when a + 1), the reading order of each side of the document is (n) after reading the first side of the first document,
(Na) Second-side reading of the first original,
Next, the (n + 1) th sheet original first side reading,
(N + 1-a) second original reading of the first original,
The document is transported so that the document reading operation is performed in this order.

  By configuring the reading order as described above, it is possible to read another document at the same time that the document is switched back, and it is possible to efficiently read a plurality of double-sided documents continuously. The apparatus can be configured compactly without increasing the size, and an inexpensive and highly productive image forming apparatus can be provided.

  The present invention further includes storage means for storing image data read by the reading unit, and control means for controlling the image data read in the reading order to be rearranged in the image forming order to perform image formation. It is characterized by having.

  As a result, even if a plurality of double-sided originals are scanned in a different order of the page order, the order can be corrected on the memory so that the image can be formed without distorting the page order. Image formation can be performed efficiently. The apparatus can be configured compactly without increasing the size, and an inexpensive and highly productive image forming apparatus can be provided.

  Further, according to the present invention, the document after the first surface reading is transported, a switchback transport operation for reversing the document, another document is transported from the separation feeding unit, and the document is moved to the reading position. At least a part of the reading / conveying operation for carrying is configured to be processed at the same time, whereby a plurality of double-sided originals can be efficiently read continuously, and a series of operations of this type of apparatus, that is, a plurality of double-sided operations are performed. Document reading and conveying operations and switchback conveying operations can be performed efficiently.

  Further, according to the present invention, the document after the first surface reading is transported, a switchback transport operation for reversing the document, another document is transported from the separation feeding unit, and the document is moved to the reading position. At least a part of the reading / conveying operation for conveying and the reverse paper discharge / conveying operation for conveying the original after double-sided reading and performing reverse discharge of the original is processed at the same time. A continuous reading of a double-sided original can be performed efficiently, and a series of operations of this type of apparatus, that is, a reading and conveying operation of a plurality of double-sided originals, a switchback conveying operation, and a reverse discharge conveying operation can be performed efficiently.

Further, the present invention is further arranged at an intermediate position between the switchback unit and the reading and conveying unit, and an inverted document is carried from the switchback unit, and the document is conveyed to the reading and conveying unit. Including an intermediate transport section,
The drive system for the transport operation of the intermediate transport unit is provided independently of the drive system for other document transport operations in the document feeder, and at least one document is retained. Even during the reading conveyance operation or the switchback conveyance operation, it becomes possible to control the original document, and the next document is made to wait in the intermediate conveyance unit, and the timing is determined by checking the reading status of other documents. The document can be fed to the reading / reading position without wasteful control, and the continuous reading of a plurality of double-sided documents can be performed efficiently.

  Hereinafter, embodiments of the present invention will be described with reference to examples shown in the drawings. This embodiment is applied to an apparatus that reads a document image while conveying a document to be read at a predetermined speed to a fixed reading unit at a document reading position. FIG. 1 is a cross-sectional view schematically showing an internal configuration of an image forming apparatus according to the present invention. A document feeder 1 (hereinafter also referred to as ADF) is mounted on an upper part of an image forming apparatus main body 200. . The ADF 1 will be described. A document setting unit A for setting a document to be read P, a separation feeding unit B for separating and feeding documents one by one from a bundle of the set documents P, and a leading edge of the fed document are temporarily abutted against each other. A registration unit C that aligns and pulls out and conveys the document after alignment, a turn unit D that turns the document conveyed from the registration unit C and conveys the document surface toward the reading side (downward), and a reading position. The slit glass 202, the reading conveyance unit E that conveys the original document from the turn part D to the reading unit 201, the switchback unit F for inverting the front and back of the original document after reading, and the switchback original document again to the registration unit The intermediate switch G for returning to C, the lower switchback unit H for temporarily waiting the document after reading the back side of the document through the turn unit D and the reading transport unit E, and the document from the lower switchback unit H are reversed. Out of the plane A reversal sheet ejection section I that discharges, and a stack portion J for holding a stack of document after reading completion. The document setting section A, switchback section F, stack section J, and lower switchback section H are arranged in layers on the same side, and turn sections D sandwiching the reading position on the opposite sides. Is arranged. The lower switchback portion H is formed on the lower surface portion of the stack portion J and can be formed without taking up a large space. In this way, the document transport path is compactly configured with a functional positional relationship.

  FIG. 2 is a block diagram showing the configuration of the control system of the image forming apparatus according to the present invention. The main body control unit 212 includes a CPU 213, a ROM 214 for storing programs, a RAM 215 for work, and an I / O interface 216. . Reference numeral 100 denotes an ADF controller, which performs drive control of a series of transport operations of the document transport unit (a document is transported by driving a roller or the like described later with a motor). The ADF controller 100 executes in response to a command from the main body control unit 212. An image reading unit 220 receives a command from the main body control unit 212 and executes a reading operation (light is applied to the original and the reflected light is converted into an electrical signal by the CCD image sensor via the optical system). . An image processing unit 221 receives an instruction from the main body control unit 212 and executes an image processing operation (color conversion processing is performed on image information such as signal shades). A page storage unit 222 stores image information for each page. An image forming unit 223 receives an instruction from the main body control unit 212 and performs an image forming operation (various image forming means, for example, a laser beam exposes a photosensitive member according to an image-processed signal and attaches toner to the recording paper. Transfer the image). A main body operation unit 211 includes a start button, a selection button, and the like, and sends an operation signal such as a start signal to the main body control unit 212.

  The document setting section A includes a document table 2, a movable table 3 provided so as to be rotatable from the end of the document table 2 in the paper feeding direction (from upstream to downstream in the document transport direction), and the width of the document P. It is comprised from the side guide (not shown) which positions in a direction (direction orthogonal to a conveyance direction). The originals P are stacked on the original table 2 with the first side (the side to be read for a single-sided original, the side to be read first for a double-sided original) facing upward. A set feeler 4 and a set sensor 5 are provided on the movable table 3 to detect the setting of the document. The set feeler 4 is pushed by the document and moved to detect the setting of the document and send a signal to the main body control unit 212. Document length detection sensors 34 and 35 (a reflection type sensor or an actuator type sensor that can detect even one document, for example, a photo interrupter actuator type) are provided on the upper surface of the document table 2, and the document conveyance direction is provided. An approximate length of is determined. It is necessary to arrange a sensor that can determine at least whether the document size is vertical or horizontal. The movable table 3 can be moved up and down in the a and b directions shown in FIG. 1 by a bottom plate raising motor 105 (the motor is not shown in FIG. 1). When a document is set, when detected by the set feeler 4 and the set sensor 5, the movable table 3 is lifted so that the bottom plate raising motor 105 is rotated forward so that the uppermost surface of the document P contacts the upper pickup roller 7. The pickup roller 7 is configured to move up and down in the c and d directions shown in FIG. When the movable table 3 is lifted, the pickup roller 7 is pushed by the upper surface of the original on the movable table 3 and moves up in the c direction. The upper limit position can be detected by the table rise detection sensor 8.

  When the start key is pressed from the main body operation unit 211 and a document feed signal is transmitted from the main body control unit 212 to the ADF 1, the pickup roller 7 rotates in the forward direction of the paper feed motor 102 (the motor is a stepping motor, for example). As a result, the roller is rotated and picks up several (ideally one) documents on the document table 2. The rotation direction is the paper feeding direction (downstream direction of the document conveying direction).

  The separation feeding unit B is located in a position opposite to the paper feeding belt 9 driven in the paper feeding direction by the normal rotation of the paper feeding motor 102, and by the normal rotation of the paper feeding motor 102. The reverse roller 10 is driven to rotate in the opposite direction to the paper feed, and the uppermost original and the lower original of the conveyed original are separated so that only the uppermost original can be fed. I have to. That is, when the reverse roller 10 is in contact with the paper feed belt 9 at a predetermined pressure and is in direct contact with the paper feed belt 9 or in a state of being in contact with one original, the reverse roller 10 is counterclockwise as the paper feed belt 9 rotates. In the unlikely event that two or more originals enter between the paper feeding belt 9 and the reverse roller 10, the reverse force is set to be lower than the torque of the torque limiter. 10 rotates in the clockwise direction, which is the original driving direction, and pushes back an extra original, thereby preventing double feeding.

  The registration portion C is composed of a pair of upper and lower pull-out rollers 12 and an abutment sensor 11. The original separated into one sheet by the action of the paper feeding belt 9 and the reverse roller 10 is further fed by the paper feeding belt 9, the leading edge of the original is detected by the abutting sensor 11, and further advances to hit the pull-out roller 12. Thereafter, the feed belt 9 is stopped by stopping the paper feed motor 102 while being fed by a predetermined distance from the detection of the abutting sensor 11 and pressed against the pull-out roller 12 with a predetermined amount of deflection. To do. At this time, by rotating the pickup motor 101, 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 is nipped between the upper and lower rollers of the pull-out roller 12. And the skew correction of the skew (original skew) is performed, and the leading edge of the original is aligned. The pull-out roller 12 is a roller for conveying the aligned original to the pair of turn rollers 14 in the turn part D, and is driven by the reverse rotation of the paper feed motor 102. At this time (during reverse rotation of the paper feed motor 102), 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 a direction orthogonal to the document conveyance direction, and detect the size of the document conveyed from the pull-out roller 12 in the width direction. Further, the length of the document in the conveyance direction can be detected from the motor pulse (the number of pulses of the stepping motor) by reading the leading edge and the trailing edge of the 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 reading transport section E. The time required to send the document to the reading unit 201 is reduced by performing (drive setting of the paper feed motor 102). Reference numeral 15 denotes a reading entrance sensor provided in the turn part D, which detects the leading edge of the document conveyed from the pull-out roller 12.

  The reading and conveying unit E includes a pair of reading inlet rollers 16, a registration sensor 17 that detects the leading edge of the conveyed document at the outlet of the reading inlet roller 16, a reading roller 19, and a pair of reading outlet rollers 21. And consists of When the leading edge of the document is detected by the reading inlet sensor 15, the reading motor starts simultaneously with decelerating to make the document conveying speed the same as the reading conveying speed before the leading edge of the document enters the upper and lower nip portion of the reading inlet roller 16. 103 (a motor is a stepping motor, for example) is driven to rotate forward to drive the reading entrance roller 16, the reading roller 19, and the reading exit roller 21. When the document is fed and the leading edge of the document is detected by the registration sensor 17, the image control sub-portion 212 is scanned with the image surface at the timing when the leading edge of the document reaches the reading unit 201 detected by the pulse count of the reading motor 103. A gate signal indicating the effective image area in the scanning direction is transmitted through the reading unit 201 until the trailing edge of the document is removed. The reading unit 201 is composed of components such as an exposure lamp, a mirror, and a lens (not shown) such as an optical system, and is provided in the apparatus main body 200. The reading unit 201 irradiates light on the image surface of the document with an exposure lamp and converts the reflected light into an electrical signal with a CCD image sensor via an optical system, and reads image information on the document.

  At the exit position of the reading exit roller 21, a paper discharge sensor 22, a lower reversing switching claw 23, and a double-side switching claw 30 are provided in the downstream direction of the conveying direction of the lower reversing switching claw 23. The lower reversing switching claw 23 is provided so as to be rotatable in the directions e and f shown in FIG. 1, and the double-side switching claw 30 is provided so as to be rotatable in the directions i and j shown in FIG. . 28 is a pair of upper and lower paper discharge rollers, and 29 is a paper discharge tray. The paper discharge roller 28 is driven by a paper discharge motor 104 (a motor is a stepping motor, for example). The paper discharge tray 29 is in the stack portion J.

  The switchback portion F is located downstream in the conveyance direction of the reading exit roller 21 and reverses the front and back of the document after reading, which is conveyed through the upper part of the lower reversing switching claw 23 and the double-side switching claw 30. Further, a pair of upper reversing rollers 31 and an upper reversing sensor 32 are included. Further, the double-side switching claw 30 forms a conveyance path in the switchback portion F in the switching state (solid line state shown in FIG. 1). This conveyance path is arranged in a positional relationship for conveying a document to the intermediate conveyance unit G via a pair of relay rollers 33. The upper reversing roller 31 is driven by an upper reversing motor 107, and the relay roller 33 is driven by a relay roller motor 108.

  The reverse discharge unit I is downstream of the reading exit roller 21 in the document conveyance direction, and the conveyance path is switched by the lower reverse switching claw 23 (in the state of the one-dot chain line shown in FIG. 1). A pair of lower reversing rollers 25, a lower reversing sensor 26, and a lower reversing paper discharge switching claw 24 are configured so as to reverse the original so as to match the orientation placed before the original is read. The lower reverse paper discharge switching claw 24 is provided to be rotatable in the directions of g and h shown in FIG. The lower reverse roller 25 is driven by the lower reverse motor 106. The reverse paper discharge unit I transports the original after reading the second image surface of the double-sided original document to the lower switchback unit H via the lower reverse roller 25, and then temporarily waits, and then the lower reverse paper discharge switching claw 24. (The state of the one-dot chain line shown in FIG. 1), the lower reverse motor 106 is driven in the reverse direction, the lower reverse roller 25 rotates in the clockwise direction, and the original is discharged from the reverse discharge portion I to the stack portion J. Are arranged in a positional relationship. Reference numeral 27 denotes an auxiliary roller, which is provided to reduce a load caused by winding a document around an inner guide plate (not shown) during conveyance.

  Next, the operation of this embodiment will be described. A case of single-sided document reading will be described. The user selects the single-side mode or the double-side mode by using the main body operation unit 211 first. The original bundle is stacked on the original table 2 with the original reading surface facing upward. When the document is set, the set sensor 5 detects and causes the bottom plate raising motor 105 to rotate forward, whereby the movable table 3 is raised and the uppermost surface of the document P comes into contact with the pickup roller 7. When a start button in the apparatus main body operation unit 211 is pressed, a signal is sent to the ADF 1 side. When the paper feed motor 102 is rotated forward by the start signal, the pickup roller 7 is rotationally driven to pick up the original on the original table 2 and convey the uppermost original in the paper feeding direction. The paper feed belt 9 and the reverse roller 10 at the tip of the paper feed direction are rotationally driven (the paper feed motor 102 is driven by normal rotation) to separate the uppermost document from the original document below it, and Only the document is transported in the feed direction. The paper feed motor 102 stops when the leading edge of the conveyed document is detected by the abutting sensor 11 and the document is fed by a predetermined distance. The conveyed document hits the pull-out roller 12 and the leading edge of the document is aligned. After the alignment, the pull-out roller 12 and the turn roller 14 are rotationally driven by the reverse rotation of the paper feed motor 102 to convey the document in the paper feed direction. When the reading entrance sensor 15 detects the leading edge of the document and rotates the reading motor 103 forward, the reading entrance roller 16, the reading roller 19, and the reading exit roller 21 are rotationally driven to convey the document in the paper feeding direction. At this time, the detection of the reading entrance sensor 15 reduces the high-speed document conveyance speed to the same speed as the reading conveyance speed. Further, when the registration sensor 17 detects the leading edge of the document, the image information of the document is read at the timing of passage of the leading edge of the document to the reading unit 201 and the start of image reading. The scanned original is conveyed in the paper feeding direction.

  In the case of single-sided document reading, the lower inversion switching claw 23 and the double-side switching claw 30 are at positions indicated by solid lines in FIG. When the paper discharge sensor 22 detects the leading edge of the document after reading, the paper discharge motor 104 is rotated forward to rotate the paper discharge roller 28 in the counterclockwise direction and discharge the original to the paper discharge tray 29. At this time, after the trailing edge of the original is detected by the paper discharge sensor 22, the driving speed of the paper discharge motor 104 is increased immediately before the rear edge of the original comes out of the upper and lower roller nips of the paper discharge roller 28 based on the pulse count of the paper discharge motor 104. Control is performed so that the document discharged on the discharge tray 29 is not popped out by being decelerated.

  Next, the next original advance operation during single-sided original reading will be described. When the abutting sensor 11 detects the trailing edge of the document, the sheet feeding motor 102 is temporarily stopped at the timing when the trailing edge of the document passes through the pull-out roller 12 by the pulse count of the sheet feeding motor 102, and is rotated again in the forward rotation direction. By this operation, the feeding operation of the next original is started. At this time, the driving of the turn roller 14 is stopped, but the timing pulley (not shown) has a built-in one-way clutch (one-way clutch that rotates in the opposite direction) so that the turn roller 14 rotates. It is configured. Therefore, the previous document is conveyed as it is. The next document fed is waiting in a state of being abutted against the pull-out roller 12. When the preceding document reaches a certain position (in the embodiment of the present invention, when the trailing edge of the document passes through the reading inlet sensor 15 and reaches the position near the reading inlet roller 16), the paper feeding motor 102 is driven in reverse. Thus, the next original is conveyed from the pull-out roller 12.

  Next, the operation for reading a double-sided document will be described. The duplex mode is set with the selection button of the main body operation unit 211. First, the original bundle is stacked on the original table 2 with the image side (first side) to be read facing upward. Press the start button of the main body operation unit 211. The operation up to the reading of the first surface (front surface) of the first document is the same as the one-side document reading described above. When the registration sensor 17 detects the leading edge of the conveyed document, the double-side switching claw 30 is moved from i to j shown in FIG. 1 by turning on a double-side switching claw solenoid (not shown). The lower inversion switching claw 23 is in a position indicated by a solid line in FIG. The first surface of the document is read by the reading unit 201 of the reading conveyance path E, and is guided to the switchback unit F through the lower reversing switching claw 23 and the upper part of the double-side switching claw 30. At this time, the next original is advanced, and the separation feeding unit B feeds the second original (FIG. 3c).

  The operation guided to the switchback portion F will be described in detail. When the paper discharge sensor 22 detects the leading edge of the first document, the paper discharge motor 104 is rotated forward to rotate the paper discharge roller 28 counterclockwise, and at the same time, the upper reverse motor 107 is driven to rotate forward. The roller 31 is rotated counterclockwise. When the trailing edge of the first original is detected by the paper discharge sensor 22, the paper discharge motor 104 and the upper reverse motor 107 are increased so as to be faster than the reading conveyance speed. Further, after the discharge sensor 22 detects the trailing edge of the document, the duplex switching claw 30 turns off the duplex switching claw solenoid at the timing when the trailing edge of the document exits the discharge roller 28 by the pulse count of the discharge motor 104. Return to j → i shown in FIG. Next, when the upper reversing sensor 32 detects the trailing edge of the document, the upper reversing motor 107 is switched from the forward rotation driving to the reverse rotation driving, whereby the upper reversing roller 31 is switched in the clockwise direction from the counterclockwise direction to rotate the original document. A switchback operation is started. At the same time, the first side of the second original is read (FIG. 3d). That is, in this state, the first document is in a switchback operation, and the second document is in a reading operation. Accordingly, continuous reading of a plurality of double-sided originals can be performed efficiently, and a series of operations of this type of apparatus, that is, a reading and conveying operation for a plurality of double-sided originals and a switchback conveying operation can be performed efficiently.

  After the leading edge of the first document reaches the relay roller 33 and is fed a predetermined amount, the relay roller 33 stops, and the first document that is switched back resides in the intermediate conveyance unit G. The relay roller 33 of the intermediate transport unit G is independently driven and controlled by the relay roller motor 108 so that the document is contained or fed to the registration unit C at a timing even when another document is in operation. It is configured to be able to. At this time, the double-sided switching claw 30 moves from i to j, and the second original read from the first side passes through the lower reverse switching claw 23 and the upper part of the double-sided switching claw 30 and is guided to the switchback portion F ( FIG. 3e). This makes it possible to control an existing document even when another document is being read and transported or during a switchback transport operation, and waits for the next document in the intermediate transport unit to read another document. It is possible to perform control without waste by feeding a document to a reading position in a timely manner according to the situation, and continuous reading of a plurality of double-sided documents can be performed efficiently.

  The second document is guided to the switchback unit F, and the first document is conveyed to the registration unit C. By driving the feeding motor 102 in reverse at this timing, the pull-out roller 12 and the turn roller 14 rotate in the paper feeding direction. The first original is sent to the registration section C and the turn section D (FIG. 3f). When the reading entrance sensor 15 detects the leading edge of the document, the paper feeding motor 102 is temporarily stopped by abutting against the reading entrance roller 16 (stopped) with a predetermined deflection by the pulse count of the paper feeding motor 102. As a result, alignment of the leading edge at the time of reading the second side of the document is performed. The document is fed into the reading and conveying section E by driving the paper feeding motor 102 in the reverse direction and driving the reading motor 107 in the normal direction again. When the registration sensor 17 detects the leading edge of the document, the lower inversion switching claw 23 moves from e to f in FIG. 1 by turning on the lower inversion switching claw solenoid (not shown). When the reading unit 201 starts reading the second surface of the document and the paper discharge sensor 22 detects the leading edge of the document, the lower reversing motor 25 is driven to rotate forward, whereby the lower reversing roller 25 rotates counterclockwise and the document is lowered. It passes through the lower part of the reverse switching claw 23 and is guided to the lower switchback part H. At this time, the third original is fed from the separation feeding unit B to the registration unit C. Further, the second document that is switched back is stopped on the intermediate conveyance path G (FIG. 3G).

  When the paper discharge sensor 22 detects the trailing edge of the document whose second surface has been read, the lower reverse switching claw 23 turns off the lower reverse switching claw solenoid by the pulse count of the lower reverse motor 106 and f → e shown in FIG. At the same time, the lower reversing motor 106 is stopped, and the rear end of the document is nipped by the lower reversing roller 25 and enters a standby state (FIG. 3h). That is, in this state, the first document is in the reverse paper discharge operation, the second document is in the standby state after the switchback operation is completed, and the third document is in the reading operation. Thus, continuous reading of a plurality of double-sided originals can be efficiently performed, and a series of operations of this type of apparatus, that is, a reading and conveying operation of a plurality of double-sided originals, a switchback conveying operation, and a reverse discharge conveying operation can be efficiently performed. .

  Thereafter, the third document is guided to the switchback unit F after the first side is read. At the same time, the second document that has been stopped by the intermediate transport unit G is transported to the registration unit C, and the operation proceeds to the second surface reading and transporting operation of the second document. At this time, the lower reverse paper discharge switching claw 24 is moved from h to g by turning on the lower reverse paper discharge switching claw solenoid (not shown) at the timing when the double-side switching claw 30 returns from j to i. Then, by driving the lower reverse motor 106 in the reverse direction, the lower reverse roller 25 and the auxiliary roller 27 are rotated in the clockwise direction, and the first original is discharged to the paper discharge tray 29. By turning off the lower reverse discharge switching claw solenoid at the timing when the leading edge of the document is sandwiched between the discharge rollers 28 by the pulse count of the lower reverse motor 106, the lower reverse discharge switching claw 24 is returned from g to h. The auxiliary roller 27 serves to reduce a load caused by winding the document around the inner guide plate. At this time, when the lower reversing sensor 26 detects the trailing edge of the document, the drive speed of the discharge motor 104 is reduced just before the trailing edge of the document is removed from the upper and lower nip portions of the discharge roller 28 by the pulse count of the discharge motor 104. Then, control is performed so that the document discharged onto the discharge tray 29 does not jump out (FIG. 3i). The above operation is repeated and a predetermined number of originals are continuously read and completed.

  In the series of operations described above, the image information of each original read by the reading unit 201 is stored in the page storage unit 222 for each page. That is, in the above-described embodiment, the original is read by reading the first side of the first original, then reading the first side of the second original, and then reading the second side of the first original. In addition, the conveyance of the original is configured so as to read in the order of the first surface of the third original. The first document first side (front side) is referred to as one page, and the second side (back side) is referred to as two pages. Hereinafter, the second document first side is referred to as three pages. Is one page, three pages, two pages, and five pages. This is stored in the page storage unit 222 for each page. Then, the image forming unit 223 forms images by rearranging the pages in order based on the stored image information. This control is configured to be performed by a command from the main body control unit 212. As a result, even if a plurality of double-sided originals are scanned in a different order of the page order, the order can be corrected on the memory so that the image can be formed without distorting the page order. Image formation can be performed efficiently. The apparatus can be configured compactly without increasing the size, and an inexpensive and highly productive image forming apparatus can be provided.

  In the above-described embodiment, one document is included in the intermediate conveyance path G. However, it is also possible to configure this document so that two documents are included in the conveyance path. A configuration may be adopted in which two originals are included in these conveyance paths including the intermediate conveyance path G and the switchback portion F. In this case, the reading order is as follows, for example. In the state where the two originals, each of which has already been read on the first side, are temporarily accumulated, the next reading is the second side of the first original after reading the first side (5 pages) of the third original. (2 pages) scanning, and then scanning is performed in the order of the first side of the fourth original (7 pages) and then the second side of the second original (4 pages). This reading order relationship can be expressed as follows using variables. When the number of documents temporarily staying in the intermediate conveyance unit G or the switchback unit F is a, and then the nth document is sent into the conveyance path (when n ≧ a + 1), the document The reading order of (n) first side reading of the (n) th original sheet, second side reading of the (n−a) th original sheet, next, (n + 1) th original sheet first side reading, (n + 1−a) sheets It can be expressed as eye document second side reading. a can be at least 1 or more. In this way, it is possible to read another document at the same time that the document is switched back, and it is possible to efficiently continuously read a plurality of double-sided documents. The apparatus can be configured compactly without increasing the size, and an inexpensive and highly productive image forming apparatus can be provided.

1 is a cross-sectional view schematically showing an internal configuration of an image forming apparatus according to the present invention. FIG. 2 is a block diagram illustrating a configuration of a control system of the image forming apparatus in FIG. 1. FIG. 3 is an explanatory diagram illustrating a conveying operation of the double-sided document of FIG.

Explanation of symbols

P Document B Separating and feeding unit E Reading and conveying unit F Switchback unit G Intermediate conveying unit I Reversed sheet discharging unit 2 Document tray 201 Reading unit 212 Main body control unit 222 Page storage unit 223 Image forming unit

Claims (8)

A document placement section for placing a plurality of documents having image information on both sides;
A separation feeding unit that separates and feeds documents one by one from the document placing unit;
A reading conveyance unit that is located downstream of the separation feeding unit and conveys the document to the document reading unit;
A switchback unit that carries in the original after reading the first side of the double-sided document, inverts the second side of the original for reading, and then conveys it to the reading and conveying unit;
An inverted paper discharge unit that carries in the original after double-sided reading, inverts the original to match the orientation placed before reading the original, and then discharges the original.
Including a document feeder having
The switchback unit includes means for temporarily retaining at least one document;
The document reading section reads the document, read and store the page reading order of the document to the page memory section, controlled to form an image by rearranging the image in page order based on the stored page storing unit of the information Forming means to
When the first sensor arranged upstream of the document reading unit detects the first document before reading the first surface, control is performed so as to form a transport path from the document reading unit to the switchback unit. First control means;
Second control means for controlling to form a conveyance path from the switchback unit to the reading conveyance unit when the second sensor arranged downstream of the document reading unit detects the trailing edge of the first document. When,
When the third sensor arranged in the switchback unit detects the first document, the switchback operation in the switchback unit is started, and the first surface reading operation and the first sheet of the second document are started. 3rd control means which controls to perform reading operation of the 2nd page of a manuscript in order,
An image forming apparatus comprising the. When the first sensor detects the first document before reading the second surface, it comprises fourth control means for controlling to form a transport path from the document reading unit to the reverse paper discharge unit. Item 2. The image forming apparatus according to Item 1. When the second sensor detects the trailing edge of the first document, a transport path is formed from the document reading unit to the switchback unit, and the first document is reversed and discharged. The image forming apparatus according to claim 2, further comprising a fifth control unit configured to perform control so that a document switchback operation and a first surface reading operation of a third document are performed simultaneously . When the number of documents temporarily staying in the switchback unit is a, and then the nth document is fed into the conveyance path (when n ≧ a + 1), the reading order of each side of the document The
(N) After reading the first side of the first original,
(Na) Second-side reading of the first original,
Next, the (n + 1) th sheet original first side reading,
(N + 1-a) second original reading of the first original,
Order image forming apparatus according to any one of claims 1, characterized in that conveying 3 a document to perform document reading operations in the. A storage unit that stores image data read by a document reading unit, and a control unit that controls to perform image formation by rearranging the image data read in the reading order in the order of image formation. Item 5. The image forming apparatus according to Item 4 . A switchback conveyance operation in which the original after the first surface reading is conveyed and the document is reversed, and a reading and conveyance operation in which another original is conveyed from the separation feeding unit and is conveyed to the reading position of the original. out at least part of the operation of the image forming apparatus according to any one of claims 1 to 5, characterized in that to process simultaneously. A switchback conveying operation for conveying the original after the first surface reading and reversing the original; a reading and conveying operation for conveying another original from the separation feeding unit and conveying the original to the reading position; document after reading both surfaces is conveyed, according to any one of claims 1, characterized in that simultaneously process at least part of the operation of the reverse discharge conveying operation for reverse discharge of the document 5 Image forming apparatus. An intermediate conveyance unit that is disposed at an intermediate position between the switchback unit and the reading conveyance unit and that receives an inverted document from the switchback unit and conveys the document to the reading conveyance unit;
Drive system of the conveying operation of the intermediate conveyance unit, independently provided from the drive system of another document conveying operation of the document feeder, claims 1, characterized in that the residence at least one document 7 The image forming apparatus according to any one of the above.

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