JP2013246383A - Image processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically release a conveyance unavailable state when an access cover is closed after opened in the sheet conveyance unavailable state.SOLUTION: An image processor comprises a drive switching mechanism for switching a drive power transmission state by a driving mechanism and a drive power transmission blocking state in association with an opening/closing operation of an access cover for opening/closing a part of a paper conveyance path. The drive switching mechanism blocks the transmission of drive power to a conveyance roller when the access cover is opened. The image processor also comprises: a DC motor for driving the conveyance roller; a control part for controlling the DC motor using a PWM value; a memory for newly storing a PWM value every time the DC motor is rotated for a prescribed amount. In a paper conveyance unavailable state, when the PWM value stored in the memory becomes below a threshold, and a new PWM value larger than the threshold is stored in the memory thereafter, the control part determines that the conveyance unavailable state is released, and shifts to a standby state where paper can be conveyed.

Description

  The present invention relates to an image processing apparatus including a roller member that conveys a sheet through an image processing unit.

  Conventionally, a reading device that separates and conveys an original document and reads an image of the original document, and a recording device that separates and conveys a recording sheet and records an image on the recording sheet are known. A facsimile or the like is known as a reading device. Examples of the recording apparatus include a printer and a copying machine. In an image processing apparatus such as a reading apparatus or a recording apparatus, a conveyed document or sheet may remain in the sheet conveyance path due to an error or the like. The image processing apparatus includes an access cover for opening a part of the conveyance path in order to remove the sheet remaining on the conveyance path.

JP 2009-296530 A

  However, the image processing device inputs that the access cover has been closed by key entry or the like when the access cover is closed again after opening the access cover due to jam (paper jam) processing, etc. There was a need to do. Unless the error state is canceled by inputting that the access cover is closed to the image processing apparatus, it is not possible to proceed to the next operation.

  Therefore, an image processing apparatus provided with a sensor for detecting opening and closing of the access cover and configured to shift to the next operation when it is detected that the access cover is closed again after the access cover is opened Has been proposed. However, with this configuration, there is a problem in that adding an electrical component including a sensor increases the size of the image processing apparatus and increases the manufacturing cost.

  The present invention has been made in view of such technical problems. SUMMARY OF THE INVENTION An object of the present invention is to provide an image processing apparatus capable of automatically canceling an unconveyable state when an access cover is closed when a document conveyance error is handled without adding a sensor.

  In order to achieve the above-described object, an image processing apparatus according to the present invention includes a roller member that conveys a sheet so as to pass through an image processing unit, a drive mechanism that transmits a driving force to the roller member, and a sheet conveyance path. An access cover for opening and closing the portion, and a drive switching means for switching between a state in which the drive mechanism transmits the driving force in conjunction with an opening and closing operation of the access cover and a state in which the transmission of the driving force is interrupted The drive switching means is an image processing device that interrupts transmission of the driving force to the roller member when the access cover is opened, and includes a DC motor for driving the roller member, and a DC motor using the PWM value. And a storage means for newly storing a PWM value every time the DC motor is rotated by a predetermined amount. When the sheet cannot be conveyed, when the PWM value stored in the storage unit becomes equal to or less than the threshold value and a PWM value larger than the threshold value is newly stored in the storage unit, the control unit cannot transfer the sheet. It is determined that the state has been eliminated, and a standby state in which the sheet can be conveyed is entered.

  According to the present invention, it is possible to automatically cancel the conveyance disabled state when the access cover is closed after being opened in response to a document conveyance error without adding a sensor.

FIG. 6 is a front cross-sectional view for explaining a sheet conveyance path of the reading apparatus according to the embodiment. 1 is an external perspective view of an image processing apparatus according to an embodiment in which a reading apparatus and a recording apparatus are integrated. FIG. 4 is a perspective view illustrating a separation unit that separates a document into one sheet in the reading apparatus according to the embodiment. In embodiment, it is a front view which shows the DC motor and drive mechanism for driving a roller member. In embodiment, it is a partial front view which shows operation | movement of the drive switching mechanism when closing an access cover, (a) The state which the access cover is open, (b) The state in the middle of closing, (c) It closed Each state is shown. In the embodiment, it is a partial front view showing the operation of the drive switching mechanism when the access cover is opened when a document is being transported, (a) the access cover is closed, (b) in the middle of opening A state, (c) shows the state further opened. 6 is a flowchart illustrating a processing sequence when a document conveyance error occurs in the reading apparatus according to the embodiment.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the present embodiment, a configuration including a reading apparatus as an image processing apparatus of the present invention will be described as an example.

  FIG. 1 is a front sectional view for explaining the sheet conveyance path of the reading apparatus according to the embodiment. FIG. 2 is an external perspective view of an image processing apparatus according to an embodiment in which a reading apparatus and a recording apparatus are integrated. FIG. 3 is a perspective view of a separation unit that separates documents one by one in the reading apparatus according to the embodiment.

  In the image processing apparatus according to the embodiment, a substantially U-shaped sheet conveyance path (hereinafter referred to as a U-turn path) 12 for conveying the document S as a sheet is arranged inside the pressure plate unit 40. The U-turn path 12 includes a separation roller 5 to which the separation pad 4 is urged, a document presence / absence sensor 16 for detecting the presence / absence of the document S, a transport roller 7 for transporting the document S, a leading end portion in the transport direction of the document S, and A document edge sensor 17 and the like for detecting the trailing edge are provided.

  In the conveyance direction of the document S, a document placement tray 14 for loading the document S is provided upstream of the U-turn path 12, and is shared with the pressure plate unit 40 on the downstream side of the conveyance path of the U-turn path 12. A document discharge tray 18 is provided. An access cover 6 for opening a part of the U-turn path 12 is provided on a part of the upper surface of the pressure plate unit 40 so as to be openable and closable. The inner surface of the access cover 6 forms a guide surface of the U-turn path 12, and when the jam of the document S occurs, the access cover 6 can be opened to perform processing such as jam removal.

  A document stopper 20, a document presence / absence sensor 16, a pickup roller 3, a separation pad 4, and a separation roller 5 are disposed upstream of the U-turn path 12 in the conveyance direction. The document stopper 20 regulates the position of the leading end in the transport direction of the document S stacked on the document placement tray 14. The document presence / absence sensor 16 is a sensor for detecting whether there is a document S to be conveyed or whether the document S is passing. The pickup roller 3 is a roller for picking up the document S in contact with the uppermost document S loaded on the document placement tray 14. Then, the document S picked up by the pickup roller 3 passes between the separation roller 5 and the separation pad 4 and is separated into only the topmost sheet. As shown in FIG. 3, the separation roller 5 and the pickup roller 3 are driven by the driving force of the DC motor M being transmitted to the separation roller shaft 24 having the clutch hub 25 and the clutch spring 26. On the other hand, a discharge roller 9 for discharging the document S to the document discharge tray 18 is disposed on the downstream side of the conveyance path of the U-turn path 12.

  As described above, the roller members for transporting the document S such as the pickup roller 3, the separation roller 5, the transport roller 7, and the paper discharge roller 9 are provided inside the pressure plate unit 40. A flat bed scanner 114 as an image processing unit is provided below the pressure plate unit 40. In this embodiment, the flat bed scanner 114 is fixed to the upper part of the recording apparatus 400, and the pressure plate unit 40 is attached to the flat bed scanner 114 so as to be openable and closable. That is, in the image processing apparatus according to the present embodiment, the reading apparatus 300 including the flat bed scanner 114 and the pressure plate unit 40 is integrated with the recording apparatus 400.

  A contact image sensor 30 for reading the document S is provided inside the flat bed scanner 114. On the upper surface of the flatbed scanner 114, a document table 22 made of a transparent plate such as glass is provided. In addition, an ADF (automatic document feed) glass 19 for reading the document S by the stopped contact image sensor 30 is disposed on the upper surface of the flat bed scanner 114 and corresponding to the lower side of the U-turn path 12. ing.

  When reading the document S placed on the document table 22, the contact image sensor 30 is moved in the left-right direction in the figure to scan and scan the document surface on the document table 22. On the other hand, when reading the document S conveyed along the U-turn path 12, the contact image sensor 30 is stopped at the position of the reading white base plate 8 and read. The contact image sensor 30 is configured, for example, to irradiate light on an original surface of an original S from an LED array as a light source, and to form an image of reflected light on a sensor element by a self-focusing rod lens array to read an image. ing.

  That is, the contact image sensor 30 is configured to be able to move in the reciprocating direction within the reading device 300. When reading the document S placed on the document table 22, the contact image sensor 30 reads the document S while scanning from the left side to the right in FIG. On the other hand, when reading the document S conveyed along the U-turn path 12, the contact image sensor 30 is stopped at the reading position shown in FIG. 1, and the document S is pressed against the ADF glass 19 by the reading white background plate 8. Read the image. The setting direction of the original S when the operator sets the original S on the original placement tray 14 is set from the right side to the left side in FIG. 1 and FIG. When the document S is set, the position of the leading end in the transport direction of the document S is regulated by the document stopper 20, and the document presence sensor 16 indicates that the document S is placed on the document placement tray 14. Detected by.

  FIG. 4 shows a front view of a DC motor and a drive mechanism for driving the roller member. As described above, the image reading apparatus includes, as a roller member for transporting the document S, the separation roller 5 that separates the document S one by one, the transport roller 7 that transports the separated document S, and the document. And a paper discharge roller 9 for discharging S. Each of these rollers 5, 7, 9 is driven by a DC motor M via a drive mechanism. The drive train from the DC motor M includes a sun gear 51, a swing arm 52, a planetary gear 53, a driven gear 54, a transport gear 55, a paper discharge gear 56, a separation gear 57, and a transmission gear train connecting the gears. Yes. An encoder wheel with a slit (not shown) is attached to the drive shaft of the DC motor M, and by reading this slit with an encoder (not shown), a rotation amount corresponding to the rotation of the DC motor M can be output. It is configured. Further, the image processing apparatus according to the embodiment includes a control unit (not shown) as a control unit that controls driving of the DC motor M.

  The DC motor M is arranged so that the motor gear 71 meshes with the sun gear 51. The sun gear 51 is formed in a double gear structure having a large diameter gear portion and a small diameter gear portion. The drive mechanism has a swing arm 52 that rotates about the same axis as the rotation axis of the sun gear 51. The planetary gear 53 that is pivotally supported by the swing arm 52 is meshed with the small-diameter gear portion of the sun gear 51. The swing arm 52 is given a predetermined friction, and the planetary gear 53 rotates as the sun gear 51 rotates. The planetary gear 53 is provided so as to be movable between a position where it is engaged with the driven gear 54 and a position where it is separated from the driven gear 54. The conveyance gear 55 is disposed on the axis of the conveyance roller 7. The paper discharge gear 56 is disposed on the shaft of the paper discharge roller 9. The separation gear 57 is disposed on the separation roller shaft 24.

  When the operator instructs the start of the reading operation by setting the document reading mode by the operation unit E according to the guidance displayed on the liquid crystal screen 70 as the display unit, the DC motor M rotates counterclockwise in FIG. Rotate to. When the DC motor M rotates counterclockwise, the sun gear 51 rotates clockwise, the swing arm 52 swings in a direction in which the planetary gear 53 meshes with the driven gear 54, and the planetary gear 53 moves the driven gear 54. Driving force is transmitted. Then, when the driven gear 54 rotates, the transport gear 55, the paper discharge gear 56, and the separation gear 57 are driven via the transmission gear train, and each of the transport roller 7, the paper discharge roller 9, and the separation roller shaft 24 is driven. Driving force is transmitted. As a result, the transport roller 7 and the paper discharge roller 9 are in a drive state in which the document S can be transported. The drive mechanism shown in FIG. 4 is composed of a drive train for transmitting a drive force from the DC motor M to the separation roller 5 as a roller member, the transport roller 7, the paper discharge roller 9, and the like.

  When the driving force is transmitted to the separation roller shaft 24, the document stopper 20 is pushed down by the pickup arm 10, and the document S is sent to the U-turn path 12 through the inclined surface of the document stopper 20 by the pickup roller 3. Then, the documents S are separated one by one by the separation roller 5 and the separation pad 4, and the uppermost document S is separated and conveyed. The original S separated into one sheet is transported along the U-turn path 12 and further transported by the transport roller 7 to a position corresponding to the reading white base plate 8 for reading by the stopped contact type image sensor 30. When the leading edge of the document S in the transport direction is detected by the document edge sensor 17, when the document S is transported from that position by a predetermined amount, the contact image sensor 30 starts reading image information while transporting the document S. Is done. While the reading operation is performed by the contact image sensor 30, the document S is pressed onto the ADF glass 19 by the reading white background plate 8.

  The document S is read at a position on the ADF glass 19 while being transported, and then discharged to the document discharge tray 18 by the discharge roller 9. When the trailing edge of the document S in the transport direction is detected by the document edge sensor 17, when the document S is transported by a predetermined amount from that position, the image information reading operation by the contact image sensor 30 is finished. Next, when the document presence / absence sensor 16 detects that the next document S is present, the document conveying operation similar to that described above is continued, and the contact image sensor 30 reads image information.

  The distance between the document S conveyed on the U-turn path 12 and the document S is determined by, for example, the peripheral speed difference between the conveyance roller 7 and the separation roller 5 or a mechanical timer provided on the pickup roller 3 or the separation roller 5. This interval is determined in consideration of the slip amount during the conveyance of the conveyance roller 7, the separation roller 5 and the pickup roller 3. Further, this interval is also determined by the amount of the next original S drawn from the original stopper 20 to the separation pad 4.

  When the reading operation of the document S by the contact image sensor 30 is completed, the DC motor M is rotated clockwise in FIG. As a result, the sun gear 51 rotates counterclockwise and the swing arm 52 also swings counterclockwise, so that the planetary gear 53 is separated from the driven gear 54, and the transport roller 7, the discharge roller 9, and the separation roller shaft No driving force is transmitted to 24. The swingable swing arm 52 and the planetary gear 53 constitute a drive switching mechanism as drive switching means.

  The drive switching mechanism is switched between a state in which the driving force is transmitted and a state in which the transmission of the driving force is interrupted according to the rotation direction of the DC motor M. The control unit rotates the DC motor M in a direction opposite to the rotation direction when the document S is conveyed to the flat bed scanner 114 (image processing unit), thereby blocking transmission of driving force by the drive switching mechanism.

  As shown in FIG. 1, since the pickup arm 10 is biased counterclockwise by a spring (not shown), the drive switching mechanism rotates in the reverse direction and the transmission of the driving force is cut off. It is rotated back to the position shown in FIG.

  Next, the operation of the drive switching mechanism when opening and closing the access cover 6 will be described. FIG. 5 shows a partial front view for explaining the operation of the drive switching mechanism when the access cover is closed. 5A shows a state in which the access cover is open, FIG. 5B shows a state in the middle of closing the access cover, and FIG. 5C shows a state in which the access cover is closed.

  As shown in FIGS. 5A to 5C, the drive switching mechanism is configured to be able to intermittently transmit drive to the drive mechanism shown in FIG. 4 in conjunction with opening and closing of the access cover 6. Yes. When the access cover 6 is opened, transmission of the driving force to the driving mechanism is released by the driving switching mechanism.

  As shown in FIG. 5, the drive switching mechanism includes a planetary gear 53 pivotally supported by the swing arm 52, and a separation position that restricts the operation of the planetary gear 53 and a separation position that does not restrict the operation of the planetary gear 53. And a movable slider 58. The slider 58 is biased to the restricted position by the slider spring 59.

  First, an operation when the access cover 6 is closed will be described. When the access cover 6 is open, as shown in FIG. 5A, the swing arm 52 is rotated counterclockwise in the drawing by the slider 58 urged in the direction a by the slider spring 59. ing. For this reason, the planetary gear 53 pivotally supported by the swing arm 52 is separated from the driven gear 54.

  The pressing force with which the slider spring 59 biases the slider 58 is set to be larger than the friction applied to the swing arm 52. For this reason, even when the DC motor M is driven, the swing arm 52 does not rotate against the pressing force received from the slider 58. Accordingly, when the access cover 6 is opened, the planetary gear 53 remains separated from the driven gear 54 and no driving force is transmitted to the roller member, so that the document S is not conveyed.

  Next, when the access cover 6 is closed, as shown in FIG. 5B, the slider restricting portion 61 provided on the access cover 6 comes into contact with the slider 58 during the closing. When the access cover 6 is further closed and is in a closed state as shown in FIG. 5C, the slider 58 is moved by the slider restricting portion 61 to a separated position where the operation of the swing arm 52 is not restricted. The slider spring 59 is moved against the biasing force. At this time, the pressing force acting on the slider restricting portion 61 from the slider 58 by the biasing force of the slider spring 59 does not act in the direction of opening the access cover 6. Further, in a state where the access cover 6 is closed, the swing arm 52 is in a state where the operation is not restricted by the slider 58. For this reason, in a state where the access cover 6 is closed, the swing arm 52 can be rotated in either the direction in which the driving force is transmitted or the direction in which the driving force is interrupted. In other words, the rotation of the planetary gear 53 in the direction in which the planetary gear 53 is engaged with the driven gear 54 by the normal rotation of the DC motor M and the direction in which the planetary gear 53 is separated from the driven gear 54 by the reverse rotation of the DC motor M. Can do.

  Next, an operation when the access cover 6 is opened while the document S is being conveyed will be described. FIG. 6 is a partial front view for explaining the operation of the drive switching mechanism when the access cover 6 is opened when the document S is being conveyed. 6A shows a state where the access cover 6 is closed, FIG. 6B shows a state where the access cover 6 is being opened, and FIG. 6C shows a state where the access cover 6 is further opened. As shown in FIG. 6A, when the access cover 6 is opened when the planetary gear 53 and the driven gear 54 are engaged with each other and the driving force is transmitted, the slider 58 by the slider restricting portion 61 of the access cover 6 Regulations are lifted. For this reason, the swing arm 52 tends to rotate in the direction in which the planetary gear 53 separates from the driven gear 54 (counterclockwise in FIG. 6) by the pressing force of the slider 58 biased by the slider spring 59.

  However, in a state where the planetary gear 53 and the driven gear 54 mesh with each other to transmit a driving force, a force that the planetary gear 53 tries to bite into the driven gear 54 is generated. Therefore, when the slider 58 presses the swing arm 52 to separate the planetary gear 53 from the driven gear 54, the rotational load generated in the swing arm 52 when the planetary gear 53 is separated from the driven gear 54. It is necessary to push with greater force. Here, when the urging force of the slider spring 59 is increased, in addition to an increase in load when the access cover 6 is closed, a large force (load) is generated when the slider 58 is held by the slider restricting portion 61. Since it will be in the state which started, it is not preferable.

  Therefore, as shown in FIG. 6B, when the access cover 6 is opened, the tip of the slider restricting portion 61 is formed so as to abut against the slider 58 and slide. The tip of the slider restricting portion 61 is configured to push the slider 58 in the same direction as the direction in which the slider spring 59 is urged by sliding on the slider 58. That is, in the present embodiment, it is considered that the swing arm 52 cannot be fully pushed by only the urging force of the slider spring 59 acting on the slider 58, and the planetary gear 53 is not separated from the driven gear 54. In the present embodiment, as described above, the tip of the slider restricting portion 61 of the access cover 6 is formed, so that the swing arm 52 can be reliably rotated using the movement of the access cover 6. ing.

  Therefore, even if a biting force is generated between the planetary gear 53 and the driven gear 54 when the driving force is transmitted, the slider restricting portion is kept until the planetary gear 53 is separated from the driven gear 54. The slider 58 can be rotated by 61. As a result, after the slider 58 is rotated by the slider restricting portion 61, the planetary gear 53 is securely moved from the driven gear 54 as in the state in which the access cover 6 is opened as shown in FIG. Can be separated from each other.

  Thus, even when the drive switching mechanism is at a position where the driving force is transmitted by the operation of opening the access cover 6, the drive switching mechanism is switched to a position where the transmission of the driving force is interrupted.

  As described above, the slider 58 is moved to the separated position by the slider restricting portion 61 provided on the access cover 6 when the access cover 6 is closed, and is restricted by the slider spring 59 when the access cover 6 is opened. Configured to be moved to. Further, when the access cover 6 is closed, the direction in which the slider 58 is pressed by the slider restricting portion 61 is not the direction in which the access cover 6 is opened. Further, the pressing force of the slider 58 by the slider spring 59 is configured to be larger than the operating force of the planetary gear 53. Further, the access cover 6 may be opened in a state where the planetary gear 53 is in a position where the driving force is transmitted to the driven gear 54 and the roller member is driven. In this case, after the slider 58 is moved in the direction in which the planetary gear 53 is separated by the slider restricting portion 61, the slider restricting portion 61 is separated from the slider 58.

  After the biting force of the planetary gear 53 is released, the urging force of the slider spring 59 is greater than the normal rotational force of the swing arm 52, so that the drive mechanism is in the same state as that shown in FIG. become.

  As described above, in a state where the access cover 6 is opened, the planetary gear 53 is separated from the driven gear 54, so that the transmission of the driving force to the driving mechanism is released.

  Next, processing control when a document conveyance error occurs during document reading will be described. FIG. 7 shows a flowchart of a processing sequence when a document transport error occurs in the image processing apparatus. When a jam of the conveyed document S or a non-feed due to slippage of the document S occurs during reading of the document, the document edge sensor 17 determines that a document transport error (untransportable state) occurs.

  That is, after the conveyance of the document S is started, if the leading edge in the conveyance direction of the document S is not detected by the document edge sensor 17 even if the document S is conveyed by a predetermined amount, it is processed as a document conveyance error. Similarly, even when the leading edge of the document S is detected and the trailing edge of the document S in the transport direction is not detected by the document edge sensor 17 even if the document S is transported by a predetermined amount, it is processed as a document transport error.

  As shown in FIG. 7, when the operation at the time of occurrence of the document conveyance error is started, the driving of the DC motor M is stopped in step S01. Next, in step S02, the pickup unit is initialized. By rotating the DC motor M clockwise in FIG. 4, the planetary gear 53 is separated from the driven gear 54, so that the driving force is not transmitted as described above, and is the same state as shown in FIG. 5C. become. At this time, since the transmission of the driving force to the conveying roller 7 and the like is interrupted, only the rotational load on the swing arm 52 is received as the driving load. At this time, a control unit having a memory as a storage unit included in the image processing apparatus stores a PWM (pulse width modulation) value = A in step S03, and opens / closes the access cover 6 based on the PWM value A. A threshold value B for determining the state is calculated. The threshold value B = (A × 1.2). The formula for calculating the threshold value B is a function of the PWM value A, but is not limited to the above formula, and is appropriately set according to the type of the DC motor M, the drive configuration, and the like. In step S04, an error message such as “Open the cover and remove the document S” is displayed on the liquid crystal screen 70, and the operator is informed of the response.

  Next, after waiting for 2 seconds in step S05, in step S06, the DC motor M is rotated forward, that is, rotated a small amount counterclockwise in FIG. And a control part newly memorize | stores PWM value = C at this time by step S07. In step S08, the control unit compares the previously calculated threshold value B with the PWM value C. If the PWM value C is greater than the threshold value B, the control unit determines that the access cover 6 has not been opened, and step S05. Return to and repeat as above. If the PWM value C is less than or equal to the threshold value B (below the threshold value), it is determined that the access cover 6 is open, and the process proceeds to step S09, such as “Remove the document and close the cover” on the liquid crystal screen 70. Display and guide the operator to the next response.

  Next, after waiting for 2 seconds in step S10, in step S11, the DC motor M is rotated counterclockwise by a small amount, and in step S12, the control unit newly stores the PWM value = D at this time. . In step S13, the control unit compares the previously calculated threshold value B with the newly stored PWM value D. If the PWM value D is equal to or less than the threshold value B, the access cover 6 is not yet closed. Determine, return to step S10, and repeat as above.

  When the PWM value D is larger than the threshold value B, it is determined that the access cover 6 is closed, and the process proceeds to step S14. In this case, the control unit determines that the unconveyable state has been resolved, and shifts to a standby state in which the document S can be conveyed. Further, the control unit shifts to the standby state, cancels the display state of the error message displayed on the liquid crystal screen 70, and displays a message such as “Set the document and press the start button” to the operator. Perform and guide the next response.

  Here, in step S06 and step S11, when the DC motor M is driven to rotate forward, when the access cover 6 is closed, the transport roller 7 is rotated in the direction in which the document S is transported. However, since the rotation amount of the transport roller 7 is small, even if the document S is set at the stacking position, the rotation amount is determined so that the pickup roller 3 stops before contacting the document S. The document S is not transported.

  As described above, when a document conveyance error occurs during document reading, the DC motor M is stopped, and then the DC motor M is reversed to separate the planetary gear 53 from the driven gear 54. At this time, the driving load of the DC motor M is the driving train load up to the planetary gear 53. On the other hand, even when the access cover 6 is opened, the planetary gear 53 is similarly separated from the driven gear 54, so that the driving load during the forward rotation of the DC motor M is the drive to the planetary gear 53. Has become a load on the column.

  Therefore, the driving load at the time of reverse rotation of the DC motor M is equal to the driving load at the time of forward rotation with the access cover 6 opened. Therefore, the PWM value at the time of reverse rotation of the DC motor M and the PWM value at the time of forward rotation with the access cover 6 opened are similarly equivalent. Further, when the access cover 6 is closed, the planetary gear 53 and the driven gear 54 mesh with each other and transmit the driving force when the DC motor M is rotating forward. Drive load increases. Therefore, when the access cover 6 is closed, the PWM value during the forward rotation of the DC motor M increases.

  That is, in the state where the drive train of the drive mechanism is blocked as shown in FIG. 5A and the state where the drive train of the drive mechanism is connected as shown in FIG. There is a difference in the driving load during normal rotation. As shown in FIG. 5A, the driving load is reduced when the drive train of the drive mechanism is shut off. Similarly, regarding the PWM value of the DC motor M, when the drive train is shut off, the PWM value is smaller than when the drive train is connected. Therefore, the threshold value of the PWM value for determining the open / closed state of the access cover 6 is set between the PWM value when the drive train is connected and the PWM value when the drive train is not connected.

  Further, in association with the PWM value at the time of reverse rotation of the DC motor M acquired when initialization is performed immediately after the jam processing, a threshold value for the PWM value is newly set each time. As a result, a high-accuracy threshold value is set that is not easily affected by differences in drive loads among devices due to variations in components and the tendency of drive trains to increase due to repeated use of devices. It becomes possible.

  As described above, the reading device of the image processing apparatus according to the embodiment includes a roller member (such as the separation roller 5, the conveyance roller 7, and the discharge roller 9) that conveys the document S through the image processing unit (flatbed scanner 114). A drive mechanism that transmits a driving force to the roller member. In addition, the reading device transmits an access cover 6 for opening a part of the conveyance path of the document S, and a state in which the driving mechanism transmits the driving force and transmission of the driving force in conjunction with the opening / closing operation of the access cover 6. A drive switching mechanism is provided for switching to a shut-off state. The drive switching mechanism interrupts transmission of the driving force to the roller member when the access cover 6 is opened.

  Further, when it is determined that the access cover 6 has been opened when a document transport error occurs, the DC motor M is driven at a predetermined time interval in the rotation direction when transporting the document S by a predetermined amount. The control unit compares the PWM value of the DC motor M driven at this time with the threshold value associated with the PWM value obtained in advance when the DC motor M is reversely rotated.

  Then, the control unit detects that the access cover 6 is closed, cancels the conveyance error state (conveyance impossible state), and guides the next operation to the operator through the liquid crystal screen 70.

  As described above, according to the embodiment, when a document conveyance error occurs without increasing the manufacturing cost due to the addition of the sensor, it is detected that the access cover 6 is closed and the conveyance error state is canceled. can do. In addition, according to the embodiment, the next operation can be guided to the operator by the liquid crystal screen 70 when the conveyance error state is canceled.

  In the above-described embodiment, the reading apparatus constituting the image processing apparatus has been described as an example as the image processing apparatus according to the present invention. The present invention is not limited to this configuration, and may be applied to a recording apparatus that conveys a recording material as a sheet and records an image on the recording material.

S Document 5 Separating roller 6 Access cover 7 Conveying roller 9 Discharging roller 30 Contact-type image sensor 51 Sun gear 52 Swing arm 53 Planetary gear 54 Driven gear 55 Conveying gear 56 Discharging gear 57 Separating gear 58 Slider 59 Slider spring 61 Slider restricting portion

Claims (5)

A roller member that conveys a sheet so as to pass through the image processing unit, a drive mechanism that transmits a driving force to the roller member, an access cover that opens and closes a part of the sheet conveyance path, and opening and closing the access cover Drive switching means for switching between a state in which the drive mechanism transmits the driving force in conjunction with an operation and a state in which the transmission of the driving force is interrupted, and the drive switching means has the access cover opened. Sometimes, an image processing apparatus that cuts off transmission of driving force to the roller member,
A DC motor for driving the roller member, a control means for controlling the DC motor using a PWM value, a storage means for newly storing a PWM value each time the DC motor is rotated by a predetermined amount, With
When the sheet cannot be conveyed, the control is performed when a PWM value greater than the threshold value is newly stored in the storage unit after the PWM value stored in the storage unit is equal to or less than the threshold value. The means determines that the unconveyable state has been resolved, and shifts to a standby state in which the sheet can be conveyed. A display unit for displaying a message about an error when the conveyance becomes impossible;
The image processing apparatus according to claim 1, wherein the display state of the message related to the error is canceled when shifting from the unconveyable state to the transportable standby state. The drive switching means is switched between a state in which the driving force is transmitted and a state in which the transmission of the driving force is interrupted according to the rotation direction of the DC motor,
The control means blocks the transmission of driving force by the drive switching means by rotating the DC motor in a direction opposite to the rotation direction when the sheet is conveyed to the image processing unit,
The image processing apparatus according to claim 1, wherein the control unit sets a new threshold value in association with a PWM value when the DC motor is rotated in the reverse direction.   When the conveyance is impossible, the control means drives the DC motor at a predetermined time interval after the PWM value stored in the storage means falls below the threshold value, and the storage means sets the PWM value. The image processing apparatus according to claim 1, which is newly stored.   The image processing apparatus according to claim 1, wherein the drive switching unit includes a planetary gear.

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