JP2007119104A - Document conveying device and copying machine mounted with it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a document conveying device further enhancing operability by suitably suppressing that an error regarding the displacement state of a movable part of a document tray is discriminated as a service man call error. <P>SOLUTION: In a positioning step (S1), when the document is placed on the document tray, the movable part of the document tray is raised to contact the document with a pickup roller. In the positioning step (S1), 1 is added to a count in every detection of the error (T1, T5, T6, T9). A conveying step (S2) is started from the time when the document is brought into contact with the pickup roller and the document is conveyed from the document tray. In the conveying step (S2), 2 is added to the count in every detection of the error (T8). The detected error is discriminated as a jam error until the count reaches a threshold value and continuation of action is allowed. The detected error is discriminated as the service man call error when the count reaches the threshold value and continuation of the action is forbidden. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a document conveying device (also referred to as an auto document feeder: ADF) mounted on, for example, a copying machine, a scanner, or a facsimile machine, and more particularly to error control thereof.

An original conveying apparatus (hereinafter abbreviated as ADF) is generally used when a plurality of originals are automatically applied to, for example, a copying machine, a scanner, or a facsimile machine (hereinafter abbreviated as a copying machine). The general mechanism of ADF is as follows (see, for example, Patent Document 1):
First, a document is placed on the document tray. At that time, the area where the document is placed generally includes a movable portion that can be displaced vertically. Next, the movable part is raised, and the uppermost one of the originals placed on the original tray is pressed against the entrance part (preferably a pickup roller) of the original conveying part. In this state, when the document conveying unit is activated, one of the documents is pulled out by the document conveying unit (especially by the rotation of the pickup roller) and sent to a predetermined position (generally, an image reading unit such as a copying machine). Subsequently, the movable part is raised again, and the next sheet of the document is pressed against the entrance portion of the document transport unit. In this way, each time the document transport unit picks up one document, the movable unit repeats the increment in small increments. As a result, the originals are automatically sent one by one from the original tray to a predetermined position.

  The displacement (vertical movement) of the movable portion of the document tray is generally fine, the movable portion repeats rising and stopping at a generally high frequency, and the above-mentioned part (pickup roller) of the document conveying portion Due to the condition that the force for pressing the document is maintained at an appropriate value, a delicate drive mechanism and highly accurate drive control for the movable part are required. Therefore, the ADF generally monitors the displacement state of the movable part (for example, the driving force (for example, motor torque) applied to the movable part, the speed of the movable part, or the time required for the predetermined displacement). In particular, when an error is detected regarding the displacement state of the movable part, the ADF stops immediately. As a result, the problems relating to the displacement of the movable portion do not reach the damage to the drive mechanism or the document.

As described above, when the ADF stops due to an error relating to the displacement state of the movable part, the error is further identified as a so-called “serviceman call error”, and the continuation of the ADF operation is prohibited. That is, the user cannot return the ADF from the error state. Thereby, unless the malfunction regarding the displacement of a movable part is removed, a movable part is not driven reliably. In this way, the problem does not surely reach the damage to the drive mechanism or the document.
JP 2005-99350 A

  However, in practice, most of the errors relating to the displacement state of the movable portion of the document tray are caused by conscious or accidental disturbance by the user with respect to the displacement of the movable portion. That is, an error often occurs when the user presses the movable part by mistake. Such an error generally does not mean that an essential failure has occurred in the drive mechanism of the movable part or its control system. In the conventional ADF, even such an error is uniformly identified as a serviceman call error, and continuation of operation is prohibited. As a result, further improvement in operability is hindered with respect to an apparatus equipped with the ADF.

  An object of the present invention is to provide a document conveying device (ADF) that further improves operability by appropriately suppressing an error relating to a displacement state of a movable portion of a document tray as a serviceman call error. To do.

An original conveying apparatus according to the present invention includes:
An original tray on which an original is placed on an area including a movable portion that can be displaced vertically;
A document transport unit that pulls out documents one by one from the document tray and sends them to a predetermined position;
Tray drive unit that moves the movable part of the document tray up and down;
A tray monitoring unit for monitoring the presence / absence of a document placed on the document tray and the displacement state of the movable part of the document tray; and
Each time an error relating to the displacement state of the movable part of the document tray is detected based on information from the tray monitoring unit, the document conveying unit and the tray driving unit are stopped, and the number of times the above error is detected is counted. Until the threshold value is reached, the continuation of the operation of the document conveyance unit and the tray drive unit is permitted, and when the count reaches the above threshold value, the continuation of the operation of the document conveyance unit and the tray drive unit is prohibited. Control unit;
Have

  In the document conveying apparatus according to the present invention, the error is identified as a serviceman call error only when the number of times the error is detected reaches a predetermined threshold. As a result, for example, to the extent that “the user accidentally pressed the movable part”, the operation of the apparatus can be maintained to be continued. Thus, the operability of the apparatus is improved.

The parameter representing the displacement state of the movable portion of the document tray preferably includes a driving force applied to the movable portion, a speed of the movable portion, or a time required for a predetermined displacement. In the above document feeder according to the present invention, an error relating to the displacement state is preferably detected as follows:
The tray driving unit raises the movable part of the document tray from the time when the document is placed on the document tray;
When the uppermost one of the documents placed on the document tray comes into contact with the entrance portion of the document conveying section by raising the movable portion of the document tray, the tray monitoring section detects the contact;
When the tray monitoring unit does not detect the contact until a predetermined time elapses after the document is placed on the document tray, the error control unit detects the state as the error.
More preferably, the tray driving unit includes a motor, and the tray monitoring unit monitors the torque of the motor, and detects an abnormal increase in the torque as the error.

  In the document conveying device according to the present invention, preferably, the error control unit weights the error detection count according to the type of the detected error. Particularly preferably, the above-mentioned error detected by the tray monitoring unit during the conveyance of the document by the document conveyance unit has a large weight for the count of the number of detections. When a document is placed on the document tray, there is a high possibility that the user will accidentally press the movable part. On the other hand, the user is less likely to make such a mistake while the document is being conveyed. Therefore, it is highly possible that the above-described error detected during the conveyance of the document actually means that an essential problem has actually occurred in the drive system of the movable part. As described above, for an error highly related to an essential defect, the weight for the count is set large. Thereby, the more such errors, the faster the count reaches the threshold, i.e. the serviceman call error occurs earlier. As a result, an essential problem occurring in the drive system of the movable part does not reach the damage of the drive mechanism or the document.

  The above document conveying apparatus according to the present invention is preferably mounted on a copying machine. The copying machine copies a document sent from a document tray to a predetermined position by a document transport unit. As a result, a large number of originals are copied automatically and at high speed. In addition, the document conveying apparatus according to the present invention may be mounted on a scanner or a facsimile machine.

  In the document conveying device according to the present invention, as described above, the number of times of error detection relating to the displacement state of the movable portion of the document tray is counted, and the error is not a serviceman call error until the count reaches a predetermined threshold. Identified. That is, unlike the conventional apparatus, the continuation of the operation is permitted in a range where the number of times of the error detection is sufficiently small. In particular, the continuation of the operation is generally not prohibited by the conscious or accidental disturbance by the user with respect to the displacement of the movable part. Thus, the operability of the document conveying apparatus according to the present invention is improved as compared with the conventional apparatus. Therefore, the document feeder according to the present invention is advantageous for use in a copying machine, a scanner, and a facsimile machine.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, exemplary embodiments of the invention will be described with reference to the drawings.
An original conveying apparatus (ADF) according to an embodiment of the present invention is preferably mounted on a copying machine, and is particularly installed on the image reading surface. In addition, it may be mounted on a scanner, a facsimile machine, or a complex machine thereof.

As shown in FIG. 1, the mechanical structure of the ADF 1 according to the embodiment of the present invention is roughly divided into a document tray 2, a document transport unit 3, a tray drive unit 4, and a paper discharge tray 7.
The document tray 2 and the discharge tray 7 are preferably arranged vertically, and the document tray 2 is connected to the entrance of the document transport unit 3 and the discharge tray 7 is connected to the exit of the document transport unit 3, respectively. A document to be copied (not shown) is placed on the document tray 2. The document transport unit 3 pulls out the documents placed on the document tray 2 one by one in order from the top, and sends them to the paper discharge tray 7 through the opening 6A and the image sensor 6B. On the paper discharge tray 7, the document discharged from the document transport unit 3 is placed. Both the document tray 2 and the paper discharge tray 7 are inclined from the horizontal direction, and the portion close to the document conveying portion 3 is lower than the other portions. As a result, the ends of the plurality of documents placed on the document tray 2 and the paper discharge tray 7 are aligned with the lower ends of the trays 2 and 7, respectively.

  The document tray 2 includes a movable portion 2A at a portion near the entrance of the document conveying unit 3 (see FIG. 1). The movable part 2A is rotatable up and down around the first end 2C far from the entrance of the document conveying part 3. That is, the second end 2D of the movable part 2A close to the entrance of the document conveying part 3 can be displaced up and down (see the second arrow U2 shown in FIG. 1). In particular, as the second end 2D rises, the uppermost one of the documents placed on the document tray 2 comes into contact with the entrance portion of the document conveying portion 3, particularly the lower portion of the pickup roller 3A (see FIG. 1). (The movable part 2A at the time of ascent is indicated by a one-dot chain line). Further, every time a document is pulled out by the pickup roller 3A, the movable portion 2A repeats rising in small increments. As a result, the next sheet of the original comes into contact with the lower portion of the pickup roller 3A.

  In a direction perpendicular to the document conveyance direction, a guide plate 2B is fixed on the end of the movable portion 2A. Since the end of the document placed on the document tray 2 in the direction perpendicular to the conveyance direction is supported by the guide plate 2B, regardless of the vertical movement of the movable portion 2A or the vibration of the entrance portion 3A of the document conveyance portion 3. The orientation of the document is maintained stably.

  A tray driving unit 4 is installed below the movable unit 2A of the document tray 2 (see FIG. 1). The tray drive unit 4 includes a shaft 4A, a support plate 4B, and a motor (not shown). The shaft 4A is installed so that the shaft can be rotated. The axis of the shaft 4A is preferably perpendicular and horizontal to the document transport direction. The upper surface of the support plate 4B faces the lower surface of the movable portion 2A of the document tray 2. The support plate 4B is fixed to the shaft 4A at the end far from the entrance of the document conveying section 3. When the shaft 4A rotates, the support plate 4B rotates about the shaft 4A, and the end close to the entrance of the document conveying unit 3 is displaced up and down (see the first arrow U1 shown in FIG. 1). . By supporting the lower surface of the movable portion 2A of the document tray 2 at the end of the support plate 4B, the movable portion 2A of the document tray 2 is displaced up and down as the shaft 4A rotates (FIG. The support plate 4B is indicated by a one-dot chain line).

A document sensor 5A is installed in a portion of the document tray 2 connected to the entrance of the document transport unit 3 (see FIG. 1). The document sensor 5A is a pressure sensor or a switch, and detects the presence or absence of a document placed on the document tray 2.
A document position sensor 5B is installed at the entrance of the document transport unit 3, particularly above the pickup roller 3A. The document position sensor 5B is a pressure sensor, and detects pressure acting upward on the pickup roller 3A (particularly pressure received by the pickup roller 3A due to contact with the document placed on the document tray 2).

  The document transport unit 3 includes a pickup roller 3A, a separation roller group 3B, a drive roller pair 3C, a main drive roller 3D, driven roller groups 3E to 3G, a drive roller 3H, a discharge roller group 3I, an upper transport path 3J, and a lower transport. Including path 3K and image sensor 6B (see FIG. 1). Each of the rollers 3A,..., 3I is preferably a cylinder and can be rotated. In particular, the axis of each roller is vertical and horizontal to the document transport direction. The pickup roller 3A is installed at the entrance portion of the document conveying section 3, and the lower portion thereof contacts the uppermost one of the documents placed on the document tray 2. When the pickup roller 3A is rotated by a motor (not shown), the documents placed on the document tray 2 are sequentially pulled out from the top, and enter the inside from the entrance of the document transport unit 3. The separation roller group 3B discharges only the uppermost one of the documents pulled out by the pickup roller 3A to the upper transport path 3J, while preventing the other documents from entering. The upper conveyance path 3J is a narrow gap in the vertical direction. The document discharged from the separation roller group 3B is sandwiched between the driving roller pair 3C and travels along the upper conveyance path 3J, and contacts the outer peripheral surface of the driving roller 3C by the driven roller 3E (broken line P1 shown in FIG. 1). reference). The document further rotates with the main driving roller 3D while being supported by the driven rollers 3E and 3F. An opening 6A is provided below the main drive roller 3D. The outer surface of the document that rotates together with the main drive roller 3D passes through the opening 6A and is scanned on the image reading surface (not shown) of the copier located further below. The scanned document is discharged to the lower conveyance path 3K by the driven roller 3G. The lower conveyance path 3K is a narrow gap in the vertical direction. The document separated from the main drive roller 3D travels along the lower conveyance path 3K and contacts the image sensor 6B by the drive roller 3H (see the broken line P2 shown in FIG. 1). Thereby, the document surface opposite to the surface scanned by the opening 6A is scanned. The scanned original is discharged from the exit of the original transport unit 3 to the paper discharge tray 7 by the paper discharge roller group 3I.

In ADF1, the control system for the above-mentioned machine part is configured as follows (see FIG. 2). The control system includes an input unit 9, a control unit 10, a document conveying unit 3, a tray driving unit 4, a tray monitoring unit 5, and an error control unit 8.
The input unit 9 is preferably an operation panel of the copying machine, and receives information related to the operation (for example, a copy start instruction) from the user. The control unit 10 is preferably a CPU, and controls the document conveying unit 3, the tray driving unit 4, the tray monitoring unit 5, and the error control unit 8 according to a predetermined program. In the document conveying unit 3, the rotation of the pickup roller 3A, the separation roller group 3B, the drive roller groups 3C, 3D, 3H, and the paper discharge roller group 3I is controlled by the control unit 10. In the tray driving unit 4, the shaft driving motor 4C is controlled by the control unit 10.

  The tray monitoring unit 5 preferably includes a torque sensor 5C in addition to the document sensor 5A and the document position sensor 5B. The torque sensor 5C detects the torque of the motor 4C of the tray driving unit 4. For the torque detection, a measured value of the current or voltage of the motor 4C is preferably used. In addition, the tray monitoring unit 5 measures the time required for a predetermined displacement by the movable unit 2A of the document tray 2. Preferably, the elapsed time from when the document is placed on the document tray 2 and the movable portion 2A starts to rise from the initial position to when the document contacts the pickup roller 3A with an appropriate pressure is measured. Further, the elapsed time from the time when the conveyance of all the originals is finished and the movable part 2A starts to descend to the time when the original part returns to the initial position is measured.

  The error control unit 8 detects an error related to the displacement state of the movable unit 2A of the document tray 2 based on information from the tray monitoring unit 5, and preferably notifies the control unit 10 of the error detection, thereby conveying the document. The unit 3 and the tray drive unit 4 are stopped. Here, for the error related to the displacement state of the movable part 2A, preferably, when the torque of the motor 4C increases abnormally, and when the predetermined displacement by the movable part 2A cannot be obtained even after a predetermined time has elapsed. , Is included. The error control unit 8 further counts the number of times the error is detected. Until the count reaches a predetermined threshold, the error control unit 8 permits the continuation of the operations of the document conveying unit 3 and the tray driving unit 4. That is, when the user instructs to resume the operation through the operation panel, the control unit 10 can restart the document conveying unit 3 and the tray driving unit 4 without being hindered by the error control unit 8. On the other hand, when the count by the error control unit 8 reaches the threshold value, the error control unit 8 prohibits the continuation of the operations of the document conveying unit 3 and the tray driving unit 4. That is, even if the user instructs to resume the operation through the operation panel, the error control unit 8 prevents the control unit 10 from restarting the document conveying unit 3 and the tray driving unit 4.

  Using the above configuration, the ADF 1 executes the document transport process as follows. FIG. 3 is a flowchart showing the entire document conveying process. The document conveyance process is roughly divided into three steps: a positioning step S1, a conveyance step S2, and an end step S3. In the positioning step S1, the position of the movable portion 2A of the document tray 2 is determined prior to document conveyance. In the transport step S2, the document is transported from the document tray 2. In the end step S3, when all the documents are conveyed, the movable portion 2A of the document tray 2 is returned to the initial position.

FIG. 4 is a flowchart showing details of the positioning step S1.
Step S11: The tray monitoring unit 5 monitors whether or not a document is placed on the document tray 2 using the document sensor 5A. If document sensor 5A detects a document, the process proceeds to step S12. Otherwise, step S11 is repeated.

Step S12: The tray monitoring unit 5 monitors the output of the document position sensor 5B, and the tray monitoring unit 5 determines whether “the pressure received by the pickup roller 3A is appropriate”. When the pressure detected by the document position sensor 5B is within a predetermined range, the positioning step S1 ends. If the pressure exceeds a predetermined range, error processing is executed (see later). If the pressure is below the predetermined range, the process proceeds to step S13.
Step S13: The tray drive unit 4 operates the motor 4C to raise the movable unit 2A of the document tray 2 by a predetermined amount. Here, the amount of increase is preferably kept constant. In addition, the higher the position of the second end 2D of the movable portion 2A, the smaller the amount of increase may be (see FIG. 1).
Step S14: The tray monitoring unit 5 monitors the torque of the motor 4C using the torque sensor 5C. When the detected torque is within the predetermined range, the process proceeds to step S15, and otherwise error processing is executed.
Step S15: The tray monitoring unit 5 measures the elapsed time from the start time of step S12. If the elapsed time is shorter than the predetermined allowable upper limit, the process returns to step S12, otherwise error processing is executed.
By repeating the loop of steps S12 to S15, the position of the movable portion 2A of the document tray 2 is determined so that the document contacts the pickup roller 3A with an appropriate pressure.

FIG. 5 is a flowchart showing details of the transport step S2.
Step S21: The control unit 10 activates the document conveying unit 3. As a result, the document in contact with the pickup roller 3A is pulled out from the document tray 2 and sent to the paper discharge tray 7 through the transport paths 3J and 3K in the document transport unit 3 (see FIG. 1). In particular, one side or both sides of the original are scanned by passing through the opening 6A in the original conveying section 3 and the image sensor 6B. Image data obtained by scanning is sent to a copying machine and printed on a predetermined sheet. Thus, the original is copied.

Step S22: The tray monitoring unit 5 monitors whether or not a document remains on the document tray 2 using the document sensor 5A. While the document sensor 5A detects the document, the process proceeds to step S23, and otherwise, the transport step S2 ends.
Step S23: The tray monitoring unit 5 monitors the output of the document position sensor 5B, and the tray monitoring unit 5 determines whether “the pressure received by the pickup roller 3A is appropriate”. As long as the pressure detected by the document position sensor 5B is within the predetermined range, step S23 is repeated. If the pressure exceeds a predetermined range, error handling is performed. If the pressure is below the predetermined range, the process proceeds to step S24.
Step S24: The tray driving unit 4 operates the motor 4C to raise the movable unit 2A of the document tray 2 by a predetermined amount. Here, the increase amount is maintained at a constant minute amount.
Step S25: The tray monitoring unit 5 monitors the torque of the motor 4C using the torque sensor 5C. When the detected torque is within the predetermined range, the process returns to step S22, and error processing is executed otherwise.
By repeating the loop of steps S22 to S25, the documents placed on the document tray 2 are conveyed one by one in order from the top.

FIG. 6 is a flowchart showing error processing in the positioning step S1 and the transporting step S2.
Step E1: The error control unit 8 detects an error related to the displacement of the movable part 2A of the document tray 2, and notifies the control unit 10 of the detection. As a result, the document conveying unit 3 and the tray driving unit 4 are quickly stopped.
Step E2: The error control unit 8 accesses the control unit 10 and confirms the operating state of ADF1. In accordance with the confirmed operation state, the error control unit 8 adds a predetermined increment to the count indicating the number of times of error detection. Preferably, when it is confirmed that the positioning step S1 is in progress, the increment of the count is set to a predetermined standard value (preferably 1) (step E3). On the other hand, when it is confirmed that the transport step S2 is in progress, the increment of the count is set to a value larger than the standard value (preferably 2) (step E4). Here, the weighting of the count may be divided more finely according to the more detailed operation state of ADF1. Thereby, the increment of the count appropriately corresponds to the seriousness and urgency of the error detected by the error control unit 8.

Step E5: The error control unit 8 determines whether or not the count indicating the number of error detections exceeds a predetermined threshold (preferably, 5).
Until the count reaches the threshold value, the error detected by the error control unit 8 is identified as a jam (paper jam) error (step E6). In this case, the occurrence of the jam is displayed on the operation panel of the copying machine, and prompts the user to perform a predetermined operation (for example, turn on the power again or open and close the cover that covers the document conveying unit 3). By this operation, the document conveying unit 3 and the tray driving unit 4 can continue to operate. In particular, the process is resumed from the positioning step S1.
When the count reaches the threshold value, the error detected by the error control unit 8 is identified as a serviceman call error (step E7). In this case, the occurrence of a service man call is displayed on the operation panel of the copying machine, and the operation by the user is rejected. In other words, the document conveying unit 3 and the tray driving unit 4 cannot continue operation by a predetermined operation by the user.

FIG. 7 is a graph showing the transition of the count by the error control unit 8.
Time T0: The first positioning step S1 is started. Here, the count is set to the initial value 0.
Time T1: When a document is placed on the document tray 2, the movable portion 2A of the document tray 2 starts to rise. At that time, since the user accidentally presses the movable part 2A, the torque of the motor 4C rapidly increases. The abnormal rise is detected by the error control unit 8 through the tray monitoring unit 5. This adds 1 to the count. Further, the occurrence of the jam is notified to the user, and the positioning step S1 is restarted by the user's predetermined operation.
Time T2: The positioning step S1 is successfully completed, and the transport step S2 is started.
Time T3: The conveyance step S2 is completed successfully. In that case, the count is reset to zero.

Time T4: The next positioning step S1 is started.
Time T5: When the document is placed on the document tray 2, the movable portion 2A of the document tray 2 starts to rise. At that time, since the user accidentally presses the movable part 2A, the torque of the motor 4C rapidly increases. The abnormal rise is detected by the error control unit 8 through the tray monitoring unit 5. This adds 1 to the count. Further, the occurrence of the jam is notified to the user, and the positioning step S1 is restarted by the user's predetermined operation.
Time T6: After the restart of the positioning step S1, a predetermined time elapses from the time when the movable part 2A of the document tray 2 starts to rise. However, contact of the document with the pickup roller 3A is not detected by the document position sensor 5B. Therefore, the error control unit 8 detects an error and adds 1 to the count. Further, the occurrence of the jam is notified to the user, and the positioning step S1 is restarted by the user's predetermined operation.

Time T7: The positioning step S1 is successfully completed, and the conveying step S2 is started.
Time T8: The torque of the motor 4C rapidly increases during document conveyance. The abnormal rise is detected by the error control unit 8 through the tray monitoring unit 5. At that time, 2 is added to the count. Further, the occurrence of the jam is notified to the user, and the positioning step S1 is restarted by the user's predetermined operation.
Time T9: A predetermined time elapses after the movable portion 2A of the document tray 2 starts to rise after the restart of the positioning step S1. However, contact of the document with the pickup roller 3A is not detected by the document position sensor 5B. Therefore, the error control unit 8 detects an error and adds 1 to the count. Thereby, the count reaches the threshold value 5. Therefore, the occurrence of a service man call is notified to the user, and the continuation of the operation by the user operation is prohibited.
Time T10: Preferably, the trouble is removed by a professional engineer and the operating state of ADF1 is reset. Accordingly, the count is reset to the initial value 0.

  In the ADF 1 according to the embodiment of the present invention, as described above, an error is identified as a serviceman call error only when the number of error detections by the error control unit 8 reaches a predetermined threshold. As a result, for example, to the extent that “the user accidentally pressed the movable part 2A”, the operation of the ADF 1 can be maintained so as to be continued. In this way, the operability of ADF1 and the copier equipped with it is improved.

  In the positioning step S1, there is a high possibility that the user will accidentally press the movable portion 2A when placing the document on the document tray 2. On the other hand, in the transport step S2, the user is less likely to make such a mistake. Therefore, the error detected by the error control unit 8 in the transport step S2 is likely to mean that an essential problem has actually occurred in the drive system of the movable unit 2A. In the ADF 1 according to the embodiment of the present invention, as described above, for an error highly related to an essential defect, the weight for the count is set large. Thereby, the more such errors, the faster the count reaches the threshold, i.e. the serviceman call error occurs earlier. As a result, an essential problem occurring in the drive system of the movable part 2A does not reach the damage of the drive mechanism or the document.

FIG. 8 is a flowchart showing details of the end step S3. In end step S3,
Step S31: The control unit 10 stops the document conveying unit 3.
Step S32: The tray driving unit 4 operates the motor 4C to lower the movable unit 2A of the document tray 2 by a predetermined amount. Here, the descending amount is preferably kept constant. In addition, the lower the position of the second end 2D of the movable portion 2A, the smaller the amount of lowering may be (see FIG. 1).
Step S33: The tray monitoring unit 5 monitors the torque of the motor 4C using the torque sensor 5C. If the detected torque is within the predetermined range, the process proceeds to step S34; otherwise, the process branches to step S36.
Step S34: The tray monitoring unit 5 monitors the position of the movable unit 2A of the document tray 2 and determines whether or not the position has returned to the initial position. Preferably, a pressure sensor or a switch (not shown) that contacts the movable part 2A when the movable part 2A stops at the initial position is used for the determination. When the movable part 2A returns to the initial position, the end step S3 ends. Otherwise, the process proceeds to step S35.
Step S35: The tray monitoring unit 5 measures the elapsed time from the start time of step S32. If the elapsed time is shorter than the predetermined allowable upper limit, the process returns to step S32; otherwise, the process proceeds to step S36.
By repeating the loop of steps S32 to S35, the movable portion 2A of the document tray 2 returns to the initial position.

Step S36: The error control unit 8 detects an error related to the displacement state of the movable unit 2A. Further, the error control unit 8 checks the number of times step S37 has been performed from the start of the end step S3 to the time point (hereinafter referred to as the number of recovery times). When the number of times of recovery is less than a predetermined upper limit (preferably 3,), the process proceeds to step S37, and otherwise, the process branches to step S38.
Step S37: The tray driving unit 4 operates the motor 4C to raise the movable unit 2A of the document tray 2 to the upper limit (this operation is called a recovery operation). Further, the error control unit 8 adds 1 to the number of recovery times. During the recovery operation, the tray monitoring unit 5 monitors the displacement state of the movable unit 2A in the same manner as steps S33 to S35. In particular, when the tray monitoring unit 5 detects an error relating to the displacement state of the movable unit 2A during the recovery operation, the process branches to step S36 (not shown).
Step S38: The error detected by the error control unit 8 is identified as a serviceman call error. Furthermore, the occurrence of a service man call is displayed on the operation panel of the copying machine, and the operation by the user is rejected. In other words, the document conveying unit 3 and the tray driving unit 4 cannot continue operation by a predetermined operation by the user.
Even if an error is detected during the return process of the movable part 2A to the initial position in steps S36 and S37, the recovery operation and the return process are repeated until the number of detections reaches a predetermined upper limit.

FIG. 9 is a graph showing the displacement of the movable portion 2A of the document tray 2 during the operation period of the ADF 1.
Time T0: The first positioning step S1 is started, and the movable part 2A starts to rise.
Time T1: The document placed on the document tray 2 comes into contact with the pickup roller 3A with an appropriate pressure due to the rising of the movable portion 2A. As a result, the process proceeds to the transport step S2. In the transport step S2, each time a document is pulled out from the document tray 2, the movable portion 2A repeats the increment in small increments.
Time T2: Since all the documents have been transported from the document tray 2, the transport step S2 ends and the end step S3 starts. Thereby, the movable part 2A starts to descend from the vicinity of the upper limit.
Time T3: Since the movable part 2A has returned to the initial position, the end step S3 ends.

Time T4: The next positioning step S1 is started, and the movable part 2A starts to rise.
Time T5: The document placed on the document tray 2 comes into contact with the pickup roller 3A with an appropriate pressure due to the rising of the movable portion 2A. As a result, the process proceeds to the transport step S2. In the transport step S2, each time a document is pulled out from the document tray 2, the movable portion 2A repeats the increment in small increments.
Time T6: Since all the documents have been transported from the document tray 2, the transport step S2 ends and the end step S3 starts. Thereby, the movable part 2A starts to descend from a position near the upper limit.
Time T7: The torque of the motor 4C rapidly increases while the movable part 2A is descending. The abnormal rise is detected by the error control unit 8 through the tray monitoring unit 5. Thereby, the first recovery operation R1 is started, and the movable part 2A starts to rise. Further, the number of recovery times is set to 1.

Time T8: Since the position of the movable part 2A has reached the upper limit, the process of returning the movable part 2A to the initial position is resumed. That is, the movable part 2A starts to descend from the upper limit position.
Time T9: The torque of the motor 4C increases rapidly while the movable part 2A is descending. The abnormal rise is detected by the error control unit 8 through the tray monitoring unit 5. Thereby, the second recovery operation R2 is started, and the movable part 2A starts to rise. Furthermore, the number of recovery times increases to 2.

Time T10: Since the position of the movable part 2A has reached the upper limit, the process of returning the movable part 2A to the initial position is resumed. That is, the movable part 2A starts to descend from the upper limit position.
Time T11: A predetermined time elapses from time T10 when the movable part 2A starts to descend. However, the movable part 2A does not return to the initial position. Accordingly, the error control unit 8 detects an error, and the third recovery operation R3 is started. Thereby, the movable part 2A starts to rise. In addition, the number of recovery increases to 3.

Time T12: Since the position of the movable part 2A has reached the upper limit, the process of returning the movable part 2A to the initial position is resumed. That is, the movable part 2A starts to descend from the upper limit position.
Time T13: A predetermined time has elapsed from time T12 when the movable part 2A started to descend. However, the movable part 2A does not return to the initial position. Accordingly, the error control unit 8 detects an error. At that time, since the number of times of recovery has reached the upper limit 3, the error detected by the error control unit 8 is identified as a serviceman call error. Furthermore, the occurrence of a service man call is displayed on the operation panel of the copying machine, and the operation by the user is rejected. That is, the document conveying unit 3 and the tray driving unit 4 cannot operate by a predetermined operation by the user.

  In the end step S3, as described above, the recovery operation is repeated every time an error relating to the displacement state of the movable part 2A is detected. In addition, an error process similar to the error process (see FIG. 6) in the positioning step S1 and the conveyance step S2 may be performed in the end step S3. In that case, a count relating to the number of times of error detection may be added throughout the positioning step S1, the transport step S2, and the end step S3.

  The present invention relates to a document feeder (ADF), and switches error processing according to the number of times of error detection as described above. Thus, the present invention is clearly industrially applicable.

1 is a schematic diagram showing a longitudinal section of an original conveying apparatus according to an embodiment of the present invention. 1 is a block diagram showing a control system of an original conveying apparatus according to an embodiment of the present invention. 6 is a flowchart showing the entire document conveying process according to the embodiment of the present invention. Flowchart showing details of positioning step S1 shown in FIG. Flowchart showing details of transport step S2 shown in FIG. Flowchart showing error processing in positioning step S1 and conveyance step S2 shown in FIG. The graph which shows transition of the count which the error control part by embodiment of this invention performs Flowchart showing details of end step S3 shown in FIG. 6 is a graph showing displacement of the movable portion of the document tray during the operation period of the document conveying device according to the embodiment of the present invention.

Explanation of symbols

1 Document feeder (ADF)
2 Document tray
2A moving parts
2B Guide plate
2C First end of movable part 2A
2D second end of movable part 2A
3 Document feeder
3A Pickup roller
3B Separation roller group
3C drive roller pair
3D main drive roller
3E, 3F, 3G driven roller group
3H Drive roller
3I Paper discharge roller group
3J Upper transport path
3K lower transfer path
4 Tray drive unit
4A shaft
4B Support plate
5A Document sensor
5B Document position sensor
6A Opening in document feeder 3
6B image sensor
7 Output tray

Claims (7)

An original tray on which an original is placed on an area including a movable portion that can be displaced vertically;
A document transport section that extracts documents one by one from the document tray and sends them to a predetermined position;
A tray driving unit that vertically moves the movable unit of the document tray;
A tray monitoring unit that monitors the presence / absence of a document placed on the document tray and a displacement state of a movable portion of the document tray; and
Each time an error relating to the displacement state of the movable part of the document tray is detected based on information from the tray monitoring unit, the document conveying unit and the tray driving unit are stopped, and the number of times the error is detected is counted. The operation of the document conveying unit and the tray driving unit is allowed to continue until the count reaches a predetermined threshold, and when the count reaches the threshold, the operation of the document conveying unit and the tray driving unit is permitted. Error control unit prohibiting continuation;
A document conveying device. The tray driving part raises the movable part of the original tray from the time when the original is placed on the original tray;
When the uppermost one of the documents placed on the document tray comes into contact with the entrance portion of the document conveying section by the rising of the movable section of the document tray, the tray monitoring section detects the contact;
If the tray monitoring unit does not detect the contact before a predetermined time elapses after the document is placed on the document tray, the error control unit detects the state as the error;
The document feeder according to claim 1. The tray driving unit includes a motor;
The tray monitoring unit monitors the torque of the motor and detects an abnormal increase in the torque as the error;
The document feeder according to claim 1.   The document conveying apparatus according to claim 1, wherein the error control unit weights the count of the number of detections according to the type of the detected error.   5. The document conveying device according to claim 4, wherein the error detected by the tray monitoring unit during conveyance of the document by the document conveying unit has a large weight with respect to the count of the number of detections.   A copying machine, comprising the document conveying device according to claim 1, wherein the document conveying unit copies a document sent from the document tray to a predetermined position. The copier has a communication unit for communicating with the outside through a predetermined communication line;
When the count exceeds the threshold, the error control unit notifies the outside through the communication unit;
The copying machine according to claim 6.

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