JP5417411B2 - Image forming apparatus - Google Patents

Description

  The present invention relates to an image forming apparatus including an apparatus main body and an upper structure that can take a closed posture covering the upper surface of the device main body and an open posture exposing the upper surface.

  2. Description of the Related Art Conventionally, as described in Patent Document 1 below, for example, an image forming apparatus including an automatic document feeder (upper structure) that is provided on an upper portion of an apparatus main body so as to be opened and closed is known. The automatic document feeder includes a document placement portion on which a document is placed and a document discharge portion. When the automatic document feeder is in a reading posture (closed posture), the automatic document feeder is placed on the document placement portion. The placed document is supplied to the document reading surface and discharged to the document discharge unit.

  In this type of image forming apparatus, if the automatic document feeder is opened and closed before the document is discharged to the document discharge unit by the automatic document feeder, the document deviates from the conveyance path. There is a possibility that the original cannot be read normally, and there is a risk of falling or paper jam. For this reason, detection means (attitude detection unit) for detecting the attitude of the automatic document feeder is provided, and the automatic document feeder is not closed by the detection means during conveyance of the document by the automatic document feeder. When this is detected, control for prohibiting the use of the automatic document feeder is performed.

JP 2009-49786 A

  However, in the image forming apparatus as described above, the user manually places another document on the document reading surface after the final document is read and before the final document is discharged. In some cases, the automatic document feeder is opened / closed as soon as possible to read. In this case, since the reading of the document has already been completed, the automatic document feeder is disabled and the final document is not discharged even though the subsequent image forming operation is not hindered. For this reason, it is necessary to wait for another document to be read until the use prohibition state of the automatic document feeder is canceled, which may cause the user to feel bothered.

  The present invention has been made in view of such circumstances, and is an image forming apparatus provided with an upper structure that can take a closed posture that covers the upper surface of the device main body and the device main body and an open posture that exposes the upper surface. An object of the present invention is to provide an image forming apparatus capable of efficiently performing a document reading operation.

  An image forming apparatus according to the present invention is an image forming apparatus including an apparatus main body, and an upper structure that can take a closed posture that covers an upper surface of the apparatus main body and an open posture that exposes the upper surface. Includes a reading unit that reads an image of a document at a predetermined reading position on the upper surface, and an image forming unit that forms an image on a sheet based on the image read by the reading unit, and the upper structure includes: A document placement unit on which a document is placed, a document discharge unit from which a document whose image has been read by the reading unit is discharged, and a document placed on the placement unit are fed out one by one, and the reading position A document transport unit that transports the document to the document discharge unit, and a document detection unit that detects the presence or absence of the document placed on the placement unit, and the image forming apparatus includes: Posture detection unit that detects posture A document passage detection unit that detects that a trailing edge of the document conveyed by the document conveyance unit has passed the reading position, and a document placed on the placement unit by the document detection unit. If it is detected and the original is being conveyed by the original conveying unit, and the closed posture is not detected by the attitude detecting unit, the original conveying by the original conveying unit is stopped, and the original detecting unit In the case where it is detected that there is no document placed on the document placement unit, the document conveyance unit is conveying the document, and the posture detection unit does not detect the closed posture, When the document passage detection unit has not detected that the trailing edge of the document has passed the reading position, the document conveyance unit stops conveying the document, while the conveyance When the document passage detection unit detects that the trailing edge of the document has passed the reading position, the document being transported to the document discharge unit is stopped without stopping the document transport by the document transport unit. And a controller for discharging.

  According to this configuration, when the document detection unit detects that there is no document placed on the placement unit, that is, when the final document is conveyed by the document conveyance unit, the upper structure is Even when it is not in the closed position, when the end of reading of the final document is detected by detecting that the trailing edge of the document has passed the reading position by the document passage detection unit. The final document is discharged to the document discharge unit without being stopped. Therefore, another document can be read immediately after the final document is discharged, and the operation of reading the next document can be efficiently performed.

  Further, the upper structure detects the document at a detection position provided upstream of the reading position in the document transport path by the document transport unit, and outputs an upstream detection signal indicating the presence or absence of the document. The document passage detection unit is preset as a distance greater than or equal to the distance from the detection position to the reading position after the signal changes from the signal indicating the presence of the document to the signal indicating the absence of the document. Preferably, when the document is transported by the document transport unit, the trailing edge of the document has passed the reading position.

  According to this configuration, even when the detection unit for detecting the document cannot be provided between the reading position and the document discharge unit due to, for example, no arrangement space, the document passage detection unit is It is possible to determine that the trailing edge of the document has passed the reading position by using an upstream detection unit that detects the document at a detection position provided upstream of the reading position.

  Alternatively, the upper structure detects the document at a detection position provided downstream of the reading position in the document transport path by the document transport unit, and outputs a signal indicating the presence or absence of the document. The document passage detection unit determines that the trailing edge of the document has passed through the reading position when the signal changes from the signal indicating the presence of the document to the signal indicating the absence of the document. preferable.

  According to this configuration, since the downstream detection unit is provided at the detection position provided downstream of the reading position, the document passage detection unit detects that the document has passed through the detection position downstream of the reading position. It is possible to accurately determine that the rear end has passed the reading position.

  According to the present invention, there is provided an image forming apparatus including an upper body that can take a closed position that covers the upper surface of the apparatus main body and the upper surface of the apparatus main body and an open position that exposes the upper surface. It is possible to provide an image forming apparatus that can perform the above-described process.

1 is a schematic cross-sectional view showing a multifunction machine as an example of an image forming apparatus according to the present invention. The schematic sectional drawing which shows an example of the upper structure which concerns on this invention. The perspective view which shows an example of the lower surface side of the upper structure shown in FIG. FIG. 3 is an exploded perspective view of a reading guide. It is a perspective view which shows an example of the attitude | position detection part which concerns on this invention, and shows the time of an upper structure being a state of an open attitude | position. It is a perspective view which shows an example of the attitude | position detection part which concerns on this invention, and shows the time of an upper structure being a closed attitude | position state. 1 is a block diagram illustrating an example of an electrical configuration of a multifunction machine. 6 is a flowchart illustrating an example of a document feeding operation using an upper structure.

  Hereinafter, a multifunction peripheral as an example of an image forming apparatus according to the present invention will be described with reference to the drawings. As shown in FIG. 1, the multifunction device 1 has a plurality of functions such as a copy, a printer, and a scanner, and is disposed on the left side of the main body (device main body) 2 and the main body 2. Arranged above the stack tray 3, an operation unit 36 for a user to input various operation commands, an image reading unit (reading unit) 4 disposed on the upper part of the main body unit 2, and the image reading unit 4. A document feeder (upper structure) 5 is provided.

  The main body 2 includes a plurality of paper feed cassettes 23, a paper feed roller 24 that feeds recording paper from the paper feed cassette 23 one by one and transports it to the image forming section 25, and a recording paper transported from the paper feed cassette 23. And an image forming unit 25 for forming an image.

  The image forming unit 25 forms a toner image on the photosensitive drum 26 and an optical unit 27 that outputs laser light or the like based on an image signal acquired by the image reading unit 4 to be described later to expose the photosensitive drum 26. A developing unit 28, a transfer unit 29 for transferring the toner image on the photosensitive drum 26 to the recording paper, and a pair of rollers 30 and 31 for fixing the toner image to the recording paper by heating the recording paper to which the toner image has been transferred. And a pair of conveyance rollers 34 and 35 that are provided in the sheet conveyance path in the image forming unit 25 and convey the recording sheet to the stack tray 3 or the discharge tray 33.

  When forming images on both sides of the recording paper, the image forming unit 25 forms an image on one side of the recording paper, and then the recording paper is nipped by the pair of conveying rollers 34 on the discharge tray 33 side. And In this state, the conveyance roller pair 34 is reversed to switch back the recording paper, and the recording paper is sent to the paper conveyance path to be conveyed again to the upstream area of the image forming unit 25, and an image is formed on the other surface by the image forming unit 25. After the formation, the recording paper is discharged to the stack tray 3 or the discharge tray 33.

  The operation unit 36 displays a start key 361 for a user to input a print execution instruction, a numeric keypad 362 for inputting the number of copies to be printed, operation guide information for various copying operations, and the like. A display unit 363 including a liquid crystal display having a touch panel function, a reset key 364 for resetting setting contents set on the display unit 363, and a stop key 365 for stopping a printing (image forming) operation being executed. A function switching key 366 for switching between a copy function, a printer function, a scanner function, and a facsimile function.

  The image reading unit 4 optically acquires an image of a document and outputs an image signal. As shown in FIG. 2, the image reading unit 4 includes a contact glass 410, a light source 42, a first mirror 431, a second mirror 432, a third mirror 433, a first carriage 46, a second carriage 47, an imaging lens 48, A CCD (Charge Coupled Device) 49 is provided. The light source 42 and the first mirror 431 are supported by the first carriage 46, and the second mirror 432 and the third mirror 433 are supported by the second carriage 47.

  The contact glass 410 includes a wide document placing glass 412 and a long and narrow document automatic reading glass 411 positioned on the left side of the document placing glass 412.

  In the image reading method of the original by the image reading unit 4, the flatbed reading mode for reading the original placed on the original placement glass 412, the original is conveyed by the original feeding unit 5, and the original is read at the reading position 413. There are two types of methods of ADF reading mode for reading a document when passing through.

  Specifically, in the flat bed reading mode, the light source 42 irradiates a document placed on the document placement glass 412, and reflected light from the document is reflected by the first mirror 431, the second mirror 432, and the third mirror. The light is reflected in the order of the mirror 433 and enters the imaging lens 48. The light incident on the imaging lens 48 is imaged by photoelectric conversion on the light receiving surface of the CCD 49 and output as an image signal. When reading for one line is completed, the first carriage 46 and the second carriage 47 move in a direction (sub-scanning direction, arrow Y direction) orthogonal to the main scanning direction of the document (direction perpendicular to the paper surface of FIG. 2). Then, the next line is read.

  On the other hand, in the ADF reading mode, as described later, when the document conveyed by the document feeding unit 5 passes through a reading position 413 that is a gap between the document automatic reading glass 411 and the reading guide 60, the light source 42 is turned on. The original is irradiated with light through the automatic original reading glass 411. The reflected light from the document is reflected in the order of the first mirror 431, the second mirror 432, and the third mirror 433, enters the imaging lens 48, and the light incident on the imaging lens 48 is reflected on the light receiving surface of the CCD 49. An image is formed by photoelectric conversion and output as an image signal. When reading of one line is completed, the document is conveyed by the document feeder 5 and reading of the next line is performed.

  As shown in FIG. 2, the document feeder 5 includes a document tray (mounting unit) 51, a pickup roller (document transport unit) 52, a separation roller (document transport unit) 53, a registration roller (document transport unit) 54, A CIS (Contact Image Sensor) 55, a pre-reading roller (original conveying unit) 56, a post-reading roller (original conveying unit) 57, a discharge roller (original conveying unit) 58, and a discharge tray (original document discharging unit) 59 are provided. (Auto Document Feeder) is configured. The document feeder 5 is provided with a document detection sensor (document detection unit) 91, a reading detection sensor (upstream detection unit) 92, and a discharge detection sensor (downstream detection unit) 93.

  The document tray 51 is a place where documents are placed. On the bottom surface of the document tray 51, there is provided a lift mechanism (not shown) that lifts the document upward, for example, by moving the lift plate with an upward biasing force. When a document is placed on the document tray 51, the lift plate is lifted upward by the lift mechanism, and the uppermost document is in contact with the pickup roller 52.

  The pickup roller 52 contacts the uppermost document on the document tray 51 and sends the document toward the separation roller 53.

  The separation roller 53 sends out the documents fed from the pickup roller 52 one by one toward the registration roller 54.

  The registration roller 54 feeds the document to the reading position 413 at an adjusted predetermined timing while forming a nip between the rollers facing each other and correcting oblique feeding of the document.

  The CIS 55 is a one-dimensional line sensor including a light emitting element and a light receiving element. The CIS 55 irradiates the back surface of the document being conveyed from the registration roller 54 to the reading position 413 with light emitted from the light emitting element. The reflected light from the surface is imaged by photoelectric conversion, and an image signal of one surface of the document is output.

  A reading guide 60 is located on the downstream side of the registration roller 54 when viewed in the document conveyance direction and between the pre-reading roller 56 and the post-reading roller 57 so as to face the contact glass 410 of the image reading unit 4. Has been placed.

  The pre-reading roller 56 is installed on the upstream side of the reading guide 60 when viewed in the document conveying direction, forms a nip with the opposing rollers, and conveys the document toward the reading guide 60. When the document passes between the reading guide 60 and the document automatic reading glass 411, the image surface of the document (the other surface of the document) is read.

  The post-reading roller 57 is installed on the downstream side of the reading guide 60 when viewed in the document conveying direction, forms a nip with the opposing roller, and conveys the document read at the reading position 413 toward the discharge tray 59. .

  The discharge roller 58 is installed on the downstream side of the post-reading roller 57 when viewed in the document conveyance direction, forms a nip with the opposing roller, and discharges the document read at the reading position 413 to the discharge tray 59.

  The discharge tray 59 is positioned below the discharge roller 58 in the vicinity of the discharge roller 58 and has a shape that is inclined upward along the discharge direction, so that discharged documents can be stacked.

  The document detection sensor 91 is provided near the lower side of the pickup roller 52, and includes, for example, a light emitting element and a light receiving element on both side surfaces (both side surfaces in a direction perpendicular to the paper surface of FIG. It consists of a light transmission type sensor. When the document is placed on the document tray 51 and the uppermost document is in contact with the pickup roller 52, the document detection sensor 91 receives light emitted from the light emitting element and is blocked by the document. To output a low-level detection signal indicating that there is a document. On the other hand, when no document is placed on the document tray 51, the light emitted from the light emitting element is received by the light receiving element, so that the light receiving element outputs a high level detection signal indicating that there is no document. To do. The document detection sensor 91 is not limited to this, and may be a light reflection type sensor. Further, the present invention is not limited to this. For example, when a protrusion urged upward by a spring or the like provided on the bottom surface of the document tray 51 touches the document and moves downward, the presence of the document is detected. It may be composed of a mechanical sensor.

  The reading detection sensor 92 is provided in the vicinity of the upstream side of the pre-reading roller 56 when viewed in the document conveyance direction, and is configured of, for example, a photo interrupter in which a light emitting unit and a light receiving unit face each other through a document conveyance path. . The reading detection sensor 92 outputs a high-level detection signal while the light emitted from the light emitting unit toward the light receiving unit is not blocked, and the light emitted from the light emitting unit toward the light receiving unit is conveyed. While the document is shielded from light, a low level detection signal is output.

  That is, when the leading edge of the document is conveyed to the reading detection sensor 92, the detection signal output from the reading detection sensor 92 is switched from the high level to the low level, and then the trailing edge of the document passes the reading detection sensor 92. Sometimes, the detection signal output from the reading detection sensor 92 is switched from the low level to the high level.

  Similarly to the reading detection sensor 92, the discharge detection sensor 93 is provided in the vicinity of the upstream side of the discharge roller 58 when viewed in the document conveyance direction. For example, the light emitting unit and the light receiving unit face each other via the document conveyance path. It consists of photo interrupters. The discharge detection sensor 93 outputs a high-level detection signal while the light emitted from the light emitting unit toward the light receiving unit is not blocked, and the light emitted from the light emitting unit toward the light receiving unit is discharged. While the document is shielded from light, a low level detection signal is output.

  That is, when the leading edge of the document is conveyed to the discharge detection sensor 93, the detection signal output from the discharge detection sensor 93 is switched from the high level to the low level, and then the trailing edge of the document passes the discharge detection sensor 93. Sometimes, the detection signal output from the discharge detection sensor 93 is switched from the low level to the high level.

  Note that the reading detection sensor 92 and the discharge detection sensor 93 are not limited to this, and may be configured by a light reflection type sensor. In addition, for example, a protrusion that is urged upward by a spring or the like provided on the lower surface of the conveyance path touches the original, moves downward, and then moves upward to confirm that the original has passed. It may be composed of a mechanical sensor such as detecting.

  The document feeder 5 also functions as a document presser. For example, as shown in FIG. 3, a main body portion is provided at a hinge portion 70 on the back side of the multifunction machine 1 (the back side of the paper in FIGS. 1 and 2). 2, and is configured to be able to take a closed posture that covers the contact glass 410 and an open posture that exposes the contact glass 410.

  A pressing plate 71 is provided on the lower surface of the document feeder 5, and the document placement glass 412 is configured to face the pressing plate 71. That is, the document feeder 5 is closed, the document placed on the document placement glass 412 is pressed by the pressing plate 71, and the user operates the operation unit 36 to cause the image reading unit 4 to display the image surface of the document. Can be read.

  As shown in FIG. 4, the reading guide 60 is long in the width direction of the document (main scanning direction), and is applied to the contact glass 410 by the urging force of the coil springs 61a and 61b provided at both ends in the length direction. It is pressed toward. The coil spring 61a is attached to the attachment portion 65a, and the coil spring 61b is attached to the attachment portion 65b.

  The lower surface of the reading guide 60 has both end portions in the length direction (solid line portions in FIG. 2) project downward from the center portion (broken line portions in FIG. 2), and the document feeder 5 is in a closed position. Both end portions in the length direction are configured to contact the contact glass 410, and the document passes through a certain gap formed between the center portion and the contact glass 410.

  Further, different guide holes 62 a and 62 b are provided at both ends in the longitudinal direction of the reading guide 60. The guide hole 62 a is disposed on the front side of the document feeding unit 5, penetrates in the vertical direction, and has a long guide rod 63 inserted in the vertical direction fixed to the document feeding unit 5. For example, the guide bar 63 has an upper end fixed to the document feeder 5, and an annular slip prevention member 63 a is attached to the lower end side below the guide hole 62 a. That is, the front side of the reading guide 60 is configured to be movable up and down along the guide rod 63.

  On the other hand, the guide hole 62 b is arranged on the back side of the document feeder 5, is formed in the front-rear direction and is elongated in the up-down direction, and projects horizontally from the document feeder 5. Has been inserted. That is, the rear side of the reading guide 60 can be moved up and down along the guide piece 64, and the reading guide 60 is movable in the up-and-down direction as a whole, and is in contact with and away from the contact glass 410. .

  In the vicinity of the front side end of the reading guide 60, a plate-like light shielding member 66 protruding upward is provided. The light shielding member 66 has a predetermined height dimension. 5 and 6 are perspective views showing an open / close detection sensor 67 provided in the vicinity of the light shielding member 66. FIG. 5 shows a state when the document feeder 5 is in an open position, and FIG. 6 shows a state when the document feeder 5 is in a closed position.

  The open / close detection sensor 67 is composed of, for example, a light transmission type sensor in which the light emitting element 67a and the light receiving element 67b face each other with the light shielding member 66 interposed therebetween. As shown in FIG. 5, when the light emitted from the light emitting element 67a is received by the light receiving element 67b, the open / close detection sensor 67 is a high-level detection indicating that the document feeder 5 is in the open position. Output a signal. On the other hand, as shown in FIG. 6, when the light that should be received by the light receiving element 67b is blocked by the light blocking member 66, the open / close detection sensor 67 causes the document feeder 5 to be jammed by the light receiving element 67b. A detection signal at a low level is output to indicate that the document feeding unit 5 is in the closed position, which floats to the extent that it exceeds the allowable height position to be generated. The open / close detection sensor 67 is not limited to this, and may be a light reflection type sensor.

  Next, the electrical configuration of the multifunction machine 1 will be described with reference to FIG. The multifunction device 1 includes a controller 80 that controls operation of each unit of the multifunction device 1. The controller 80 is composed of, for example, a microcomputer including a CPU and a memory such as a ROM or a RAM, and performs operation control of each unit by executing various control programs stored in the memory by the CPU.

  The controller 80 is connected to the image reading unit 4, the image forming unit 25, the various detection sensors 67, 91, 92, 93 and the various rollers 52, 53, 54, 56, 57, 58 so as to communicate with each other. ing.

  For example, the controller 80 causes the CPU to execute a control program that functions as a motor control unit 81, a document passage detection unit 82, and a paper feed abnormality detection unit (control unit) 83, thereby feeding a document by the document feeding unit 5. Control the operation.

  The motor control unit 81 outputs a drive signal to each motor (not shown) that drives the various rollers 52, 53, 54, 56, 57, and 58, and sets the various rollers 52, 53, 54, 56, 57, and 58 in advance. Control is performed to rotate at a predetermined speed. Each motor is constituted by, for example, a stepping motor, and is rotated by a predetermined angle according to the number of pulses of the drive signal.

  The document passage detection unit 82 detects that the trailing edge of the document conveyed via the various rollers 52, 53, 54, 56, 57, 58 has passed the reading position 413.

  Specifically, the document passage detection unit 82 changes the detection signal output from the reading detection sensor 92 from a low level signal indicating the presence of a document to a high level signal indicating the absence of a document, and then the pre-reading roller 56. When the number of pulses of the drive signal of the motor that drives the motor reaches a predetermined number of pulses, it is detected that the document has passed the reading position 413.

  The predetermined number of pulses, for example, conveys the document by a distance from the position (detection position) where the reading detection sensor 92 is arranged to the reading position 413 based on experimental values such as test operation. Therefore, the number of pulses equal to or greater than the number of pulses of the drive signal when the motor that drives the pre-reading roller 56 is rotated is determined.

  The paper feed abnormality detection unit 83 detects that there is a document placed on the document tray 51 by the document detection sensor 91 and closes the document feed unit 5 by the open / close detection sensor 67 while the document is being transported. If no is detected, the various rollers 52, 53, 54, 56, 57, and 58 are stopped, and control for stopping the conveyance of the document is performed.

  In addition, the paper feed abnormality detection unit 83 detects that there is no document placed on the document tray 51 by the document detection sensor 91, and the document detection unit 67 detects whether or not the document feed unit 5 detects that the document is being conveyed. When the closed posture is not detected and the document passage detection unit 82 does not detect that the trailing edge of the document has passed the reading position 413, the rollers 52, 53, 54, 56, 57, and 58 are stopped. Then, control for stopping the conveyance of the document is performed.

  On the other hand, the paper feed abnormality detection unit 83 detects that there is no document placed on the document tray 51 by the document detection sensor 91, and the opening / closing detection sensor 67 during document transportation detects the document feed unit 5 of the document feed unit 5. When the closed position is not detected and the document passage detection unit 82 detects that the trailing edge of the document has passed the reading position 413, the various rollers 52, 53, 54, 56, 57, and 58 are stopped. Instead, the document being conveyed is discharged to the discharge tray 59.

  Hereinafter, the flow of the document feeding operation using the document feeding unit 5 will be described with reference to FIG.

  When the controller 80 starts an operation of reading a document in the ADF reading mode based on, for example, a copy function execution instruction input from the operation unit 36, the motor control unit 81 causes the various rollers 52, 53, 54, Driving of the driving motors 56, 57, and 58 is started, and feeding of the uppermost document on the document tray 51 is started (S1).

  The paper feed abnormality detection unit 83 is a low level indicating that the document feed unit 5 is in the closed position from the open / close detection sensor 67 while the document is being conveyed by the various rollers 52, 53, 54, 56, 57, 58. When the detection signal is output (S2; YES), the detection signal output from the discharge detection sensor 93 is switched from the low level to the high level, that is, when the trailing edge of the document has passed the discharge detection sensor 93. Until it is detected that the document being conveyed is discharged to the discharge tray 59 (S3; NO), the conveyance of the document by the various rollers 52, 53, 54, 56, 57, and 58 is continued. When the document being conveyed is discharged to the discharge tray 59 (S3; YES), the process returns to step S1, and feeding of the next document, that is, the uppermost document on the document tray 51 is started.

  On the other hand, the feeding error detection unit 83 outputs a high level detection signal indicating that the document feeding unit 5 is in the open position from the open / close detection sensor 67 during document conveyance (S2; NO). ), It is detected by the document detection sensor 91 whether or not a document is placed on the document tray 51 (S4).

  When a document is placed on the document tray 51 and a low-level detection signal indicating that there is a document is output by the document detection sensor 91, that is, when a document that is not the final document is being conveyed (S4) YES), the paper feed abnormality detection unit 83 instructs the motor control unit 81 to stop the driving motors of the various rollers 52, 53, 54, 56, 57, and 58, thereby conveying the document. Is stopped (S5). The feeding error detection unit 83 displays a message on the display unit 363 that, for example, the document feeding unit 5 has been opened while the document is being conveyed in accordance with the execution of step S5. You may comprise so that a user may be notified of the reason for having stopped conveyance.

  Further, when a document is not placed on the document tray 51 and the document detection sensor 91 outputs a high-level detection signal indicating that there is no document, that is, the final document is being conveyed. In this case (S4; NO), even after the conveyance of the final document is started, the document passage detection unit 82 does not detect that the document has passed the reading position 413 (S6; NO). The paper abnormality detection unit 83 executes step S5.

  In step S6, when it is not detected by the document passage detection unit 82 that the document has passed the reading position 413, the paper feed abnormality detection unit 83 executes step S5 and, for example, for the last document. Since the document feeder 5 is opened during reading, a message indicating that the final document needs to be read again is displayed on the display unit 363 to notify the user that the final document needs to be read again. You may comprise.

  On the other hand, when the high-level detection signal indicating that there is no original is output by the original detection sensor 91, that is, when the final original is being conveyed (S4; NO), the final original When the document passage detection unit 82 detects that the document has passed the reading position 413 (S6; YES), the paper feed abnormality detection unit 83 outputs from the discharge detection sensor 93. When the detected signal is switched from the low level to the high level, that is, when the trailing edge of the final document has passed through the discharge detection sensor 93, the final document being conveyed passes the discharge roller 58 after a predetermined time has elapsed. The final document is conveyed by the various rollers 52, 53, 54, 56, 57, 58 until it is detected that it has passed and discharged to the discharge tray 59 (S 7; NO). It is continued.

  In step S6, when it is detected by the document passage detection unit 82 that the document has passed the reading position 413, the paper feed abnormality detection unit 83 indicates, for example, a message that the document reading is finished. May be displayed on the display unit 363 to notify the user that the reading of the document has been completed.

  When it is detected that the final document being conveyed has been discharged to the discharge tray 59 (S7; YES), the paper feed abnormality detection unit 83 makes the rollers 52, 53, The drive motors 54, 56, 57, and 58 are instructed to stop, whereby the document feeding operation using the document feeding unit 5 is completed.

  As described above, according to the configuration of the above embodiment, even when the document feeder 5 is not in the closed position during the conveyance of the final document, the trailing edge of the document is positioned at the reading position 413. When the end of reading of the final document is detected by detecting the passage by the document passage detection unit 82, the final document is discharged to the discharge tray 59 without being stopped. . Therefore, another document can be read immediately after the final document is discharged, and the operation of reading the next document can be efficiently performed.

  In the above-described embodiment, the document passage detection unit 82 detects that the detection signal output from the reading detection sensor 92 in step S6 (FIG. 8) is a low level signal indicating that there is a document to a high level signal indicating that there is no document. When the number of pulses of the drive signal of the motor that drives the pre-reading roller 56 reaches a predetermined number of pulses after the change to, it is configured to detect that the document has passed the reading position 413. .

  For this reason, even if a detection sensor for detecting a document cannot be provided between the reading position 413 and the discharge tray 59 because, for example, there is no arrangement space, the document passage detection unit 82 is used. Using the reading detection sensor 92 that detects the document at the detection position provided upstream of the reading position 413, it was possible to determine that the trailing edge of the document passed the reading position 413.

  However, in place of this configuration, the document passage detection unit 82 detects that the detection signal output from the discharge detection sensor 93 has a high level indicating that there is no document from a low level signal indicating that there is a document in step S6 (FIG. 8). When the signal is changed, that is, when the final document is discharged to the discharge tray 59, it may be determined that the trailing edge of the document has passed the reading position 413.

  In this case, since the discharge detection sensor 93 is provided downstream of the reading position 413, the document passage detection unit 82 reads the trailing edge of the document when the document passes through a position downstream of the reading position 413. It is possible to accurately determine that the position 413 has been passed. Note that, for example, a sensor for detecting a document is separately provided downstream of the reading position 413, such as between the post-reading roller 57 and the discharge detection sensor 93, and instead of the discharge detection sensor 93, the separately provided sensor is used to detect the document. When the passage is detected, it may be determined that the trailing edge of the document has passed the reading position 413.

  In the above-described embodiment, a multifunction peripheral is described as an example of the image forming apparatus according to the present invention. However, the present invention can also be applied to an image forming apparatus such as a printer, a copier, a scanner, or a FAX. is there.

  In the above embodiment, the configurations and settings shown in FIGS. 1 to 8 are merely examples, and the present invention is not limited to the embodiment. For example, the document feeder 5 may have a simplified configuration that does not include the CIS 55 (FIG. 2). Further, for example, information shown when various signals are at a high level or a low level may be configured to have a meaning opposite to that in the above embodiment.

1 MFP (image forming device)
2 Main unit (device main unit)
25 Image forming unit 36 Operation unit 4 Image reading unit (reading unit)
413 Reading position 5 Document feeder (upper structure)
51 Document tray (stack)
52 Pickup roller (document feeder)
53 Separation roller (original transport section)
54 Registration Roller (Document Feeder)
56 Pre-reading roller (document feeder)
57 Post-reading roller (document feeder)
58 Ejection roller (document feeder)
59 Ejection tray (original output)
67 Open / close detection sensor (posture detection unit)
70 Hinge unit 80 Controller 81 Motor control unit 82 Document passage detection unit 83 Paper feed abnormality detection unit (control unit)
91 Document detection sensor (document detection unit)
92 Reading detection sensor (upstream detection unit)
93 Discharge detection sensor (downstream detector)

Claims (3)

An image forming apparatus comprising: an apparatus main body; and an upper structure that can take a closed posture that covers an upper surface of the device main body and an open posture that exposes the upper surface.
The apparatus main body is
A reading unit that reads an image of a document at a predetermined reading position on the upper surface;
An image forming unit that forms an image on a sheet based on an image read by the reading unit;
The upper structure is
A placement unit on which the document is placed;
A document discharge unit for discharging a document whose image has been read by the reading unit;
A document transport unit that feeds the documents placed on the placement unit one by one and transports them to the document discharge unit via the reading position;
A document detection unit that detects the presence or absence of a document placed on the placement unit,
The image forming apparatus includes:
A posture detection unit for detecting the posture of the upper structure;
A document passage detection unit that detects that the trailing edge of the document conveyed by the document conveyance unit has passed the reading position;
When it is detected by the document detection unit that there is a document placed on the placement unit, the document is being conveyed by the document conveyance unit, and the closed posture is not detected by the posture detection unit Stops the conveyance of the document by the document conveyance unit, the document detection unit detects that there is no document placed on the placement unit, and the document conveyance unit is conveying the document. In the case where the closed posture is not detected by the posture detection unit, when the document passage detection unit does not detect that the trailing edge of the document being conveyed has passed the reading position, the document conveyance unit While the conveyance of the document is stopped, the document conveyance is detected when the document passage detection unit detects that the trailing edge of the document being conveyed has passed the reading position. Image forming apparatus and a control unit for discharging the document in the conveyance without stopping the conveyance of the document to the document discharge section by. The upper structure is
An upstream detection unit for detecting the document at a detection position provided upstream of the reading position in the document transport path by the document transport unit and outputting a signal indicating the presence or absence of the document;
The document passage detection unit
After the signal changes from the signal indicating the presence of the document to the signal indicating the absence of the document, the document is moved by the document transport unit by a predetermined distance that is set in advance as a distance from the detection position to the reading position. The image forming apparatus according to claim 1, wherein when the document is conveyed, it is determined that the trailing edge of the document has passed the reading position. The upper structure is
A downstream detection unit that detects the document at a detection position provided downstream of the reading position in the document transport path by the document transport unit and outputs a signal indicating the presence or absence of the document;
The document passage detection unit
The image forming apparatus according to claim 1, wherein when the signal changes from a signal indicating the presence of the document to a signal indicating the absence of the document, it is determined that the trailing edge of the document has passed the reading position.

Images