JP2014049958A - Image reading device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technology for surely detecting that a switch gear has been switched from a carriage side position to a conveyance part side position in the case of switching the switch gear from the carriage side position to the conveyance part side position.SOLUTION: An image reading device includes: a sensor disposed in a conveyance path for detecting an original; a motor; a switch gear; and a control part. The switch gear is switched between a carriage side position (FB side position) where a motor side transmission gear is connected to a carriage side transmission gear for transmitting a power to a carriage and a conveyance part side position (ADF side position) where a motor side transmission gear is connected to a conveyance part side transmission gear for transmitting a power to a conveyance part for conveying an original. The control part executes detection processing of allowing the sensor to detect the original while allowing the motor to rotate in a direction where the switch gear is switched from the FB side position to the ADF side position (S125).

Description

  The present invention relates to an image reading apparatus, and more particularly, to an image reading apparatus in which a conveying device that conveys a sheet-like document to a reading unit such as a CIS and a moving device that moves the reading unit are operated with the power of one motor.

  2. Description of the Related Art Conventionally, as an image reading apparatus that operates a conveyance device (conveyance unit) that conveys a sheet-like document to a reading unit such as CIS and a moving device (carriage) that moves the reading unit with the power of one motor, for example, What was described in patent document 1 is known. According to this image reading apparatus, a position where the transmission unit (switching gear) that transmits the drive of the motor transmits power to the conveyance device (a position on the conveyance unit side) and a position where the transmission unit transmits power to the moving device (carriage) By switching between the first position and the second position, the conveying device and the moving device can be operated by a single motor.

JP 2006-86817 A

  However, when switching the switching gear from the carriage side position to the conveyance unit side position, it may not be possible to reliably detect that the switching gear has been switched from the carriage side position to the conveyance unit side position. For example, when the detection of switching of the switching gear is to be performed by the control amount of the motor, for example, the number of driving steps of the motor, if the torque required for the gear switching operation varies, the predetermined driving step required for the gear switching operation Even if the motor is rotated by a number, the switching operation is not completed. In this case, it is necessary to rotate the motor with a further number of driving steps in order to complete the gear switching operation. As described above, when detection of switching of the switching gear is performed based on the number of driving steps, when the number of driving steps varies, it is ensured that the switching gear is switched from the carriage side position to the conveyance unit side position. There was a possibility that it could not be detected.

  Accordingly, the present invention provides an image reading apparatus that can reliably detect that the switching gear has been switched from the carriage side position to the conveyance unit side position when switching the switching gear from the carriage side position to the conveyance unit side position. is there.

An image reading apparatus disclosed in this specification is provided in a reading unit that reads an image of a document, a transport unit that transports a document, a transport path in which the document is transported by the transport unit, and the transport path. A sensor that detects the document, a carriage that holds the reading unit and moves in a predetermined direction, a motor, a motor-side transmission gear that transmits power supplied by the motor, and the conveyance unit. A conveyance side transmission gear that transmits the power to the conveyance unit at the time of conveyance reading for reading a document, and a carriage side that transmits the power to the carriage at the time of moving reading for reading an image by moving the carriage. A transmission gear and a conveyance gear that connects the motor-side transmission gear and the conveyance unit-side transmission gear in a state where the carriage is in a conveyance reading position that is a document reading position during the conveyance reading. Meshed with the transport unit side transmission gear at the part side position, and meshed with the carriage side transmission gear at the carriage side position connecting the motor side transmission gear and the carriage side transmission gear during the movement reading. A switching gear for switching, and a control unit, wherein the control unit is configured to feed a document to the sensor while rotating the motor in a direction to switch the switching gear from the carriage side position to the transport unit side position. It is comprised so that the detection process which detects may be performed.
According to this configuration, when the switching gear is switched from the carriage side position to the conveyance unit side position, if the document is detected by the sensor provided in the conveyance path, the switching gear reaches the conveyance unit side position. Probability is high. In other words, it is possible to detect that the switching gear has been switched to the transport unit side position by detecting the document with a sensor provided in the transport path.

The image reading apparatus includes a request receiving unit that receives a document reading request, the sensor is provided on the upstream side of the document transport with respect to the reading unit in the transport path, and the control unit receives the request When the unit accepts a document reading request and a document is detected in the detection process, the reading unit may be configured to execute a start process to start reading the document.
According to this configuration, since the document reading can be started based on the timing when the document is detected by the sensor, the document reading can be started without being affected by the error of the motor drive control when the switching gear is switched. For this reason, it is possible to suppress document reading defects accompanying the switching operation of the switching gear.

In the image reading apparatus, the control unit causes the reading unit to read a document based on a switching speed that is a rotation speed of the motor for switching the switching gear in the start process. A first speed switch for switching the rotational speed of the motor from the switching speed to a reading speed for reading a document that is different from the switching speed during the reading of the document by the reading unit under a switching speed. A process and a post-switching reading process that causes the reading unit to read the document based on the reading speed may be executed.
Depending on how fast the reading speed for reading the document, which is the rotational speed of the motor, the document may reach the reading position before the rotational speed of the motor reaches the reading speed. In this case, if the image of the original is read by the reading unit after reaching the reading speed, the read image until the reading speed is reached is lost. However, according to this configuration, even when the document reaches the reading position before the rotational speed of the motor reaches the reading speed, the document can be read, thereby preventing image loss. Can do.

In the image reading apparatus, the control unit may be configured to read a document that is different from the switching speed for changing the rotation speed of the motor from the switching speed for switching the switching gear before the start process. A second speed switching process for switching to a speed and a post-switching reading process for causing the reading unit to read the document based on the reading speed may be executed.
According to this configuration, there is no need to perform read data conversion processing associated with the rotation speed change. Therefore, when the motor is shared for conveyance reading and moving reading, when reading a document related to conveyance reading, the reading speed is switched to a reading speed for reading the document, and the document is read at a reading speed suitable for reading the document. be able to.

Further, in the image reading apparatus, the control unit, when executing the speed switching process, a stop process for stopping conveyance of a document conveyed under the switching speed of the motor, and the speed switching process. Thereafter, a re-conveying process for conveying the original to the conveying unit may be performed based on the reading speed.
According to this configuration, when the speed is changed from the switching speed to the reading speed, the stop process is executed, so that the document can be transported more stably than when the stop process is not performed. That is, if the rotational speed of the motor is switched while the document is being transported, the document transport speed will change during the transport of the document, which may cause disturbance in the transport of the document. However, by stopping the conveyance of the original and switching the rotation speed of the motor, the possibility of such an irregular conveyance of the original can be avoided.

In the image reading apparatus, the control unit is configured to control the switching speed of the motor for switching the switching gear from the detection of the leading edge of the document until the trailing edge of the document is detected in the detection process. In addition, a conveying process for conveying the document to the conveying unit, a reading process for causing the reading unit to read the document conveyed based on the switching speed, and the switching speed of the motor, Switching to a reading speed for reading a document, which is different from the switching speed, and based on the reading speed, a subsequent transport process for transporting a subsequent document following the document to the transport unit, and a source of the reading speed And a subsequent reading process for causing the reading unit to read the subsequent document conveyed to the printer.
Normally, if the switching gear is switched at the motor rotation speed (reading speed) at the time of carrying and reading, the torque is insufficient, so the motor rotation speed needs to be reduced to a predetermined switching speed. Therefore, conversely, when the switching of the switching gear is completed and the conveyance reading is performed, it is necessary to change the motor rotation speed from the switching speed to the reading speed. At this time, if the motor rotation speed is changed while the document is being conveyed, there is a concern about a decrease in image quality due to the change in the motor rotation speed. However, it is possible to suppress a decrease in image quality due to a change in the motor rotation speed by reading the document conveyed at the switching speed at the switching speed.

In the image reading apparatus, the control unit is configured to execute an acquisition process for acquiring a setting value for switching speed for reading the document based on the switching speed before the reading process. You may make it do.
According to this configuration, by acquiring the setting value for reading the document based on the switching speed, the document can be read using the switching speed setting value suitable for the switching speed, and the switching speed Originally, it is possible to suppress a decrease in image quality associated with reading a document.

The image reading apparatus further includes a storage unit that stores image data obtained by the reading process, and the control unit creates switching speed image data according to the setting value for switching speed in the reading process. The created switching speed image data is stored in the storage unit, and the switching speed image data stored in the storage unit is set according to a setting value for reading speed for reading the document based on the reading speed. It may be configured to execute a conversion process for converting into image data for reading speed created in this way.
According to this configuration, by performing the conversion process for converting the switching speed image data of the document read at the switching speed into the image data for the reading speed, a difference in image quality occurs between the document and the subsequent document. Can be suppressed.

In the image reading apparatus, the switching speed setting value may include a resolution corresponding to the switching speed, and the reading speed setting value may include a resolution corresponding to the reading speed.
According to this configuration, the image data of the document read at the switching speed is subjected to the conversion processing of the image data related to the resolution, thereby suppressing the difference in image quality between the document and the subsequent document. Can do.

In the image reading apparatus, the switching speed setting value may include the number of colors corresponding to the switching speed, and the reading speed setting value may include the number of colors corresponding to the reading speed.
According to this configuration, the image quality between the original and the subsequent original is obtained by converting the number of colors, that is, the image data relating to the color original or the monochrome original, on the image data of the original read at the switching speed. It can suppress that a difference arises.

In the image reading apparatus, the document includes a plurality of documents, and the document read in the reading process is a first document among the plurality of documents, and is read in the subsequent reading process. The succeeding document may be a document after the second of the plurality of documents.
According to this configuration, it is possible to minimize the number of documents that need to be subjected to the image data conversion process in accordance with the rotation speed change. Thereby, it is possible to reduce the time required for the image data conversion process, and hence the reading time.

The image reading apparatus further includes a designation receiving unit that receives a designation of a reading range that is a range in which the reading unit reads a document by a user, and the control unit detects the leading edge of the document in the detection process. Then, the switching determination for determining whether or not to execute a speed switching process for switching the rotation speed of the motor from a switching speed for switching the switching gear to a reading speed for reading a document that is different from the switching speed. In the switching determination process, it is determined to execute the speed switching process outside the reading range received by the designation receiving unit, and within the reading range received by the designation receiving unit. Thus, it may be determined not to execute the speed switching process.
According to this configuration, by performing the speed switching process outside the reading range, it is possible to suppress a decrease in image quality associated with the switching process when the speed switching process is performed within the reading range.

The image reading apparatus further includes a document tray on which a first document and a succeeding document subsequent to the first document are placed, and the control unit operates the transport unit. If the leading edge of the succeeding document is not detected by the sensor within a predetermined time, it is determined that the succeeding document is idle, and the leading edge of the succeeding document is detected by the sensor within a predetermined time after operating the transport unit. In such a case, it may be configured to execute a blank feeding determination process for determining that the subsequent document is not blank fed.
In the case of the first document, since the motor is driven at a switching speed for switching the switching gear, if the friction of the document is strong, it may take more time than necessary to feed the document by the feed roller. It is done. In this case, a predetermined feeding time elapses, and the fact that the paper is not actually fed is erroneously detected as idle feeding. However, in the case of the first document, it is not determined that the paper is not fed, so that erroneous detection can be avoided. Furthermore, in the second and subsequent sheets, it is possible to detect air transport as usual.

  According to the present invention, when the switching gear is switched from the carriage side position to the conveyance unit side position, it can be reliably detected that the switching gear is switched from the carriage side position to the conveyance unit side position.

The perspective view which shows the external appearance of the multifunctional machine containing an image reading apparatus 1 is a schematic cross-sectional view of an image reading apparatus according to a first embodiment. Explanatory drawing which shows the case where a planetary gear exists in FB side position Explanatory drawing showing the case where the planetary gear is at the ADF side position Block diagram schematically showing the electrical configuration of the MFP 6 is a flowchart illustrating ADF reading processing according to the first embodiment. 10 is a flowchart showing ADF reading processing according to the second embodiment. 10 is a flowchart showing ADF reading processing according to the third embodiment. 10 is a flowchart showing ADF reading processing according to the fourth embodiment.

<Embodiment 1>
Next, Embodiment 1 will be described with reference to FIGS.

1. 1 is a multifunction peripheral device having a printer function, a scanner (document reading) function, a copy function, a facsimile function, and the like.

  As shown in FIG. 1, the multifunction machine 1 includes an image reading device 3 for reading a document above the main body 2. As shown in FIG. 2, the image reading device 3 includes a reading unit 30, a carriage 34, an automatic document feeder (ADF) device 40, a document placing unit 50, a reading drive unit 60 (see FIG. 5) and the like. . As an image reading method, the image reading apparatus 3 moves the carriage 34 to read an image, and performs FB reading (moving reading) and ADF reading (conveying reading) that reads a document conveyed by the conveying units 44 and 45 (see FIG. 2). ). The image reading device 3 is not limited to a part of the multifunction device 1. For example, the image reading device may be a single scanner device or a copier.

  As shown in FIG. 2, the document placement section 50 includes an underframe 51, a first platen glass 52 made of a transparent glass plate, a second platen glass 53, and an intermediate frame disposed between the glasses 52 and 53. 54. The upper surface of the first platen glass 52 is covered with a rotatable document cover 48.

  Further, a home position detection mark 55 is provided on the intermediate frame 54, and the mark 55 includes, for example, a white tape 55A and a black tape 55B arranged in the sub-scanning direction. A position where the data read by the reading unit 30 changes from black to white or from white to black is detected as the home position HP. Here, the home position HP may be a standby position where the reading unit 30 waits when the reading unit 30 is not executing an image reading process for reading an image of the document 5 placed on the first platen glass 52. In addition, it is set as a reference position for movement control of the carriage 34 when performing an FB (flat bed) reading operation.

  That is, when the driving amount (in this embodiment, the number of driving steps) for driving the motor 62 after the reading unit 30 detects the home position HP reaches a predetermined driving amount, the first platen glass 52 by the reading unit 30 is used. Scanning of the document 5 placed on is started. In other words, when the motor 62 is driven by a predetermined number of FB reading start steps and the reading unit 30 reaches the reading start position PS shown in FIG. 2 from the home position HP, the reading unit 30 scans the document 5. To start. When the motor 62 is driven by a predetermined number of FB reading end steps and the reading unit 30 reaches the reading end position PE shown in FIG. 2 from the home position HP, the reading unit 30 scans the document 5. finish. Thus, the home position HP is set as a reference position when the reading unit 30 performs reading scanning. Therefore, the home position HP detection process is performed as an example of the initialization process of the reading unit 30.

  The document cover 48 is pivotable between a closed posture covering the first platen glass 52 and an open posture opening the first platen glass 52 (the operation unit 11 and the display unit). The side on which 12 etc. are provided is connected to the front side). An ADF device 40 is provided on the document cover 48.

  As shown in FIG. 2, the ADF apparatus 40 includes an ADF cover 41, a document tray 42, a transport path 43, various rollers such as a transport roller 44, a paper feed roller 44 </ b> A, and a paper discharge roller 45, and the top surface of the document cover 48. Including a paper discharge tray 46. The ADF device 40 conveys the originals 5 placed on the original tray 42 one by one, passes them over the second platen glass 53, and discharges them to the paper output tray 46. Further, a rear sensor (an example of a sensor) 47 such as a photosensor for detecting the document 5 conveyed by the conveyance roller 44 and a front such as a photosensor for detecting the document 5 set on the document tray 42. A sensor 49 is provided.

  The rear sensor 47 is provided in the conveyance path 43 on the upstream side of the document conveyance with respect to the reading unit 30. On the document tray 42, when there are a plurality of documents 5, the first document 5 and the subsequent document 5 following the first document are placed. Here, the conveyance path 43, the conveyance roller 44, the paper supply roller 44 </ b> A, and the paper discharge roller 45 correspond to an example of a conveyance unit that conveys the document 5.

  The reading unit 30 is provided below the document placing unit 50 as shown in FIG. Here, the reading unit 30 is configured to read a document by a CIS (Contact Image Sensor) method. The reading unit 30 linearly reflects reflected light reflected by a linear image sensor 33 in which a plurality of light receiving elements are linearly arranged in the direction perpendicular to the paper surface, a light source 31 including RGB light emitting diodes, a document 5, and the like. A rod lens array 32 that forms an image on each light receiving element of the image sensor 33 is included. The carriage 34 that holds the reading unit 30 is coupled to the timing belt 35, and moves in the arrow A direction or the B direction as the timing belt 35 moves. The timing belt 35 is driven by a read driving unit 60 described later via a sprocket or the like (not shown). The reading unit 30 is not limited to the CIS method, and may be a so-called CCD method using a reduction optical system and a CCD (charge coupled device) image sensor.

  When reading the document 5 placed on the first platen glass 12, that is, when executing the FB reading, the reading unit 30 uses the carriage 34 coupled to the timing belt 35 to move the first platen glass from the home position HP. The original 5 is read while being conveyed at a constant speed in a direction parallel to the board surface 52 (direction A in FIG. 2). At this time, the reading range in the transport direction is, for example, from the reading start position PS to the reading end position PE shown in FIG.

  On the other hand, when the reading unit 30 reads the document 5 conveyed by the ADF device 40, that is, when executing the ADF reading, the reading reading unit 30 (ADF reading position) RP immediately below the second platen glass 53 by the carriage 34. The original 5 is read while being held in the position. That is, in this embodiment, the carriage 34 moves along a path from the ADF reading position RP to the reading end position PE.

  Furthermore, an operation unit (an example of a request reception unit and a specification reception unit) 11 including various buttons and a display unit 12 including, for example, a liquid crystal display are provided on the front side of the multifunction machine 1. The operation unit 11 includes a start button 11A for starting a reading operation.

2. Configuration of Reading Drive Unit Next, the reading drive unit 60 will be described with reference to FIGS. 3 to 5. The reading drive unit 60 includes a motor drive unit 61, a motor 62, and a gear unit 70.

  The motor 62 is a stepping motor, and the motor drive unit 61 generates a drive signal for step-driving the motor 62 in accordance with the control of the CPU 20. The drive signal for the stepping motor is normally a pulse signal having a predetermined frequency, and the rotation speed of the motor 62 is switched by, for example, switching the frequency of the pulse signal.

  The gear unit 70 includes a motor side transmission gear 71, a carriage side transmission gear 72, a conveyance unit side transmission gear 73, and a planetary gear mechanism 74. The planetary gear mechanism 74 includes a transmission gear 74A, a sun gear 74B, and a planetary gear 74C.

  The motor-side transmission gear 71 is coupled to the rotation shaft of the motor 62 and is coupled to the transmission gear 74A of the planetary gear mechanism 74. Therefore, the motor-side transmission gear 71 transmits the power supplied by the motor 62 to the transmission gear 74A according to the rotation of the motor 62. The sun gear 74B and the transmission gear 74A are regulated on the same axis, and the sun gear 74B rotates according to the rotation of the transmission gear 74A, that is, according to the rotation of the motor side transmission gear 71.

  The planetary gear 74C is coupled to the sun gear 74B, and rotates and revolves according to the rotation of the sun gear 74B. The position of the planetary gear 74C is such that the planetary gear 74C is coupled to the carriage-side transmission gear 72, and the motor-side transmission gear 71 and the carriage-side transmission gear 72 are connected via the transmission gear 74A and the sun gear 74B. (Hereinafter referred to as “FB side position”), the planetary gear 74C is coupled to the transport unit side transmission gear 73, and the motor side transmission gear 71 and the transport unit side transmission gear 73 are similarly connected to the transmission gear 74A and the sun gear. The position is switched to the transport unit side position (hereinafter referred to as “ADF side position”) connected via 74B. FIG. 3 shows a case where the planetary gear 74C is at the FB side position, and FIG. 4 shows a case where the planetary gear 74C is at the ADF side position.

  When reading is performed at each position, the planetary gear 74C is prevented from revolving by a predetermined blocking mechanism (not shown), and rotates in response to the rotation of the sun gear 74B while being held at each position. Shall. In addition, when the position of the planetary gear 74C is switched, the planetary gear 74C revolves according to the rotation of the sun gear 74B in a state where the prevention of revolution by the blocking mechanism is released.

  As shown in FIG. 3, the carriage-side transmission gear 72 transmits the power from the motor 62 to the carriage 34 via the timing belt 35 when the planetary gear 74 </ b> C is at the FB side position, that is, when the moving reading is executed. . As a result, the carriage 34 moves.

  As shown in FIG. 4, when the planetary gear 74C is at the ADF side position, that is, when carrying out conveyance reading, as shown in FIG. 4, the conveyance unit side transmission gear 73 is conveyed via a predetermined gear mechanism (not shown) or the like. 44, the power from the motor 62 is transmitted to the paper discharge roller 45. As a result, the document 5 is conveyed.

  Hereinafter, the operation of the reading drive unit 60 will be described in more detail. 3 and 4, the rotation direction in the X direction is a clockwise rotation direction, and the rotation direction in the Y direction is a counterclockwise rotation direction. The motor-side transmission gear 71 rotates in the X direction according to the rotation of the motor 62 in the X direction, and rotates in the Y direction according to the rotation of the motor 62 in the Y direction.

2-1. For example, when the planetary gear 74C is not coupled to the carriage-side transmission gear 72 or the conveyance unit-side transmission gear 73, the motor 62 is rotated in the X direction at the position where the planetary gear 74C is not coupled to the carriage-side transmission gear 72 or The gear 71 rotates in the X direction, and accordingly, the transmission gear 74A and the sun gear 74B rotate in the Y direction. As the sun gear 74B rotates in the Y direction, the planetary gear 74C revolves in the L direction while rotating in the X direction. As shown in FIG. 3, when the planetary gear 74C is coupled to the carriage-side transmission gear 72 and reaches the FB side position, the planetary gear 74C rotates in the X direction, but the carriage-side transmission gear 72 causes the L of the planetary gear 74C to rotate. Directional revolution is prevented. At this time, the restriction of the carriage 34 by a predetermined restricting member (not shown) is released. Further, the carriage-side transmission gear 72 rotates in the Y direction, and accordingly, the timing belt 35 moves the carriage 34 in the A direction in FIG. 2, that is, the direction from the reading start position PS to the reading end position PE. Move to.

  On the other hand, when the carriage 34 is at a position other than the ADF reading position RP, the motor 62 rotates in the Y direction, so that the motor side transmission gear 71 rotates in the Y direction, and accordingly, the transmission gear 74A and the sun gear 74B are Rotate in the X direction. As the sun gear 74B rotates in the X direction, the planetary gear 74C rotates in the Y direction, but is prevented from revolving in the R direction by the blocking mechanism. At this time, the carriage-side transmission gear 72 rotates in the X direction, and accordingly, the timing belt 35 moves the carriage 34 in the B direction of FIG. 2, that is, in the direction from the reading end position PE to the reading start position PS. Move in the direction.

  When the carriage 34 moved in the B direction in FIG. 2 reaches the ADF reading position RP, the regulating member, for example, the carriage 34 is urged in the direction of the platen glass 52, 53 (perpendicular to the A and B directions). The movement of the carriage 34 in the A and B directions is restricted by the elastic body (for example, a coil spring). Further, the blocking of the planetary gear 74C from revolving in the R direction by the blocking mechanism is released, and the planetary gear 74C revolves in the R direction while rotating in the Y direction. As shown in FIG. 4, when the planetary gear 74 </ b> C is coupled to the transport unit side transmission gear 73 to the ADF side position, the planetary gear 74 </ b> C rotates in the Y direction, but the planetary gear 74 </ b> C is rotated by the transport unit side transmission gear 73. Revolution in the R direction is prevented. At this time, the conveyance unit side transmission gear 73 rotates in the X direction as the planetary gear 74C rotates in the Y direction. With the rotation of the conveyance unit side transmission gear 73 in the X direction, the conveyance roller 44 and the paper discharge roller 45 rotate.

  On the other hand, when the motor 62 rotates in the X direction, the motor side transmission gear 71 rotates in the X direction, and accordingly, the transmission gear 74A and the sun gear 74B rotate in the Y direction. As the sun gear 74B rotates in the Y direction, the planetary gear 74C is prevented from revolving in the R direction and revolves in the L direction while rotating in the X direction.

  In the present embodiment, the rotation direction in the X direction of the motor 62 corresponds to the second rotation direction, and the rotation direction in the Y direction of the motor 62 corresponds to the first rotation direction. However, the present invention is not limited thereto, and a configuration in which the rotation direction in the X direction of the motor 62 is the first rotation direction and the rotation direction in the Y direction of the motor 62 is the second rotation direction may be employed.

2-2. Operation of Each Gear for ADF Reading In ADF reading, the motor 62 is moved in the Y direction (counterclockwise) so that the planetary gear 74 </ b> C rotates in the Y direction and revolves in the R direction coupled to the transport unit side transmission gear 73. In the case of rotation, if the motor 62 continues to rotate in the Y direction even after the planetary gear 74C is coupled to the conveyance unit side transmission gear 73, the conveyance roller 44 and the discharge roller 45 cause the document 5 to be discharged from the document tray 42 to the discharge tray. Rotate in the direction of transport to 46

  Further, when the motor 62 is rotated in the X direction after the planetary gear 74C is coupled to the transport unit side transmission gear 73, the planetary gear 74C rotates in the X direction and is separated from the coupled transport unit side transmission gear 73. Revolve in the L direction. Note that the transport unit side transmission gear 73 rotates only in the X direction.

2-3. Operation of Each Gear Related to FB Reading In FB reading, when the motor 62 is rotated in the X direction so that the planetary gear 74C rotates in the X direction and revolves in the L direction coupled to the carriage side transmission gear 72, the planetary gear 74C If the motor 62 continues to rotate in the X direction even after the gear 74C is coupled to the carriage side transmission gear 72, the carriage side transmission gear 72 is moved in the Y direction so that the timing belt 35 moves the carriage 34 in the A direction in FIG. To drive.

  Further, when the motor 62 is rotated backward from the X direction to the Y direction after the planetary gear 74C is coupled to the carriage-side transmission gear 72, the planetary gear 74C rotates in the Y direction. However, the planetary gear 74C rotates in the Y direction without revolving in the R direction by the blocking mechanism that prevents the planetary gear 74C from revolving in the R direction away from the carriage-side transmission gear 72 that has been coupled. At this time, the carriage-side transmission gear 72 rotates in the reverse direction in the X direction, whereby the timing belt 35 is driven in a direction to move the carriage 34 in the B direction in FIG.

  When the timing belt 35 is driven in the direction of moving the carriage 34 in the direction B of FIG. 2 and the carriage 34 reaches a position where it cannot physically move, in this case, the ADF reading position RP, the planetary gear revolves by the blocking mechanism. The blockage is released, and the operation of each gear related to the conveyance reading starts.

  As for the blocking mechanism, for example, a lever that pivotally supports the planetary gear 74C, a groove cam that restricts swinging of the lever, a spring that maintains the state of the transmission gear 73, etc. It is realizable by comprising.

3. As shown in FIG. 5, the MFP 1 includes a CPU 20 (an example of a control unit), a ROM 21, a RAM 22, an NVRAM (nonvolatile RAM) 23, a network interface (an example of a reception unit) 24, and a facsimile interface. 25, to which an image forming unit 27, a reading unit 30, an operation unit 11, a display unit 12, a rear sensor 47, a front sensor 49, a reading driving unit 60, and the like are connected.

  Various programs for controlling the operation of the multifunction device 1 are stored in the ROM 21, and the CPU 20 controls each unit while storing the processing results in the RAM 22 or the NVRAM 23 according to the programs read from the ROM 21. . Further, for example, a ROM (an example of a storage unit) 21 stores reading parameters such as resolution.

  The network interface 24 is connected to an external computer or the like via a communication line (not shown), and mutual data communication is possible via the network interface 24. It is also possible to receive a reading start instruction from an external computer via the network interface 24.

  The facsimile interface 25 is connected to a telephone line (not shown), and facsimile data can be communicated with an external facsimile apparatus or the like via the facsimile interface 25. The image forming unit 27 includes a well-known charging unit, exposure unit, photoconductor, developing unit, transfer unit, and fixing unit, and based on image data of an image (original) read by the image reading device 3 Is formed on the paper.

  The CPU 20 controls various processes related to the multifunction machine 1. Further, the CPU 20 executes ADF reading processing described below as processing related to the image reading device 3. In the ADF reading process, the CPU 20 executes a detection process in which the rear sensor 47 detects the document 5 while rotating the motor 62 in the direction of switching the planetary gear 74C from the carriage side position to the transport unit side position.

  In the configuration of the image reading device 3, when the CPU 20 rotates the motor 62 in one rotation direction (Y direction) in order to move the carriage 34 in the movement direction B in FIG. 2, the carriage 34 has a maximum movement distance. Then, the planetary gear 74C is moved from the reading end position PE where the reading of the original is finished to the switching position where the planetary gear 74C is switched from the FB side position to the ADF side position via the reading start position PS where the reading of the original is started (see FIG. 2). ). This switching position is the ADF reading position RP in this embodiment. The switching position is not limited to this.

  Further, as described above, when the carriage 34 reaches the ADF reading position RP, movement of the carriage 34 is restricted by the restriction member. Then, the planetary gear 74C starts switching from the FB side position to the ADF side position after the carriage 34 is restricted from being moved by the restricting member, and the transport units 44 and 45 are configured so that the planetary gear 74C is at the ADF side position. The document 5 rotates in the direction in which the document 5 is conveyed.

4). ADF Reading Process Next, the ADF reading process in the first embodiment will be described with reference to FIG. The ADF reading process is executed when the document 5 is detected by the front sensor 49 and, for example, a document reading request is made via the start button 11A. Each process related to the ADF reading process is executed by the CPU 20 according to a predetermined control program stored in the ROM 21 or the like, for example.

  In the first embodiment, it is assumed that “the distance from the document detection position of the rear sensor 47 to the ADF reading start position RP” is shorter than “the switching speed through-down distance + the reading speed through-up distance”. That is, in the first embodiment, the distance from the document detection position of the rear sensor 47 to the ADF reading start position RP is relatively short, and the document 5 is in the ADF reading start position while the rotation speed of the motor 62 is switched from the switching speed to the reading speed. It is assumed that RP is reached and reading of the document 5 is started.

  In the ADF reading process, as shown in FIG. 6, the CPU 20 first obtains a setting value for switching speed and a setting value for reading speed for reading the document 5 based on the switching speed (step S100). : An example of acquisition processing). Here, each setting value is, for example, resolution and / or number of colors. Here, for example, a resolution of 1200 dpi is set in the ROM 21 as the setting value for the switching speed. The CPU 20 reads and acquires a resolution of 1200 dpi from the ROM 21. As described above, by acquiring the setting value for the switching speed for reading the document 5 based on the switching speed, the document 5 can be read using the setting value suitable for the switching speed. Therefore, it is possible to suppress a decrease in image quality associated with reading a document.

  On the other hand, as a setting value for reading speed for reading the document 5 based on the reading speed, for example, when a resolution of 600 dpi is set by the user from the operation unit 11, the CPU 20 sets the resolution of 600 dpi from the operation unit 11. get. Next, the CPU 20 acquires correction data for reading speed from, for example, the RAM 22 (step S105), and acquires correction data for switching speed from, for example, the RAM 22 (step S110).

  Here, the reading speed usually means the rotation speed of the motor 62 set for the ADF reading operation. The reading speed is usually determined according to the resolution and / or the number of colors of document reading. Here, the number of colors corresponds to monochrome reading and color reading. That is, in the case of monochrome reading, the number of colors is “1”, and in the case of color reading, the number of colors is “3”, for example.

  Further, the correction data for reading speed means correction data relating to document reading when the motor 62 is rotated at the reading speed, that is, when a normal ADF reading operation is performed. The reading speed correction data includes known shading correction data and the like. The shading correction data is generated based on the reflected light from the white tape 55A, for example, by moving the carriage 34 to the home position HP and irradiating the white tape 55A with light by the reading unit 30. Further, the shading correction data is generated according to at least one of the document reading resolution and the number of colors.

  On the other hand, the switching speed means the rotational speed of the motor 62 when the planetary gear 74C is switched from the FB side position to the ADF side position, and the rotational speed is different from the reading speed. Further, the correction data for the switching speed means correction data relating to document reading when the ADF reading operation is performed while the rotation speed of the motor 62 remains at the switching speed. The correction data for the switching speed includes well-known shading correction data and the like, similar to the correction data for the reading speed, and the shading correction data is generated according to at least one of the resolution and the number of colors, for example. Therefore, the data value of the shading correction data is different for the reading speed and the switching speed.

  Next, the CPU 20 rotates the motor 62 in the Y direction for a predetermined number of steps to move the carriage 34 from the home position HP to the ADF reading position RP (step S115), and further switches the motor 62 in the Y direction for a predetermined switching. The planetary gear 74C is switched from the FB side position to the ADF side position by rotating at a speed (step S120).

  Next, the CPU 20 causes the document 5 to be conveyed by driving the conveyance unit via the planetary gear 74 </ b> C while the motor 62 is further rotated in the Y direction at the switching speed. Then, the CPU 20 determines whether or not the front end of the document 5 is detected by the rear sensor 47 (step S125: an example of detection processing). That is, the CPU 20 executes a detection process in which the rear sensor 47 detects the document 5 while rotating the motor 62 in the direction of switching the planetary gear 74C from the FB side position to the AFD side position. If it is determined that the leading edge of the document 5 is not detected by the rear sensor 47 (step S125: NO), the CPU 20 continues the rotation of the motor 62 in the Y direction at the switching speed. On the other hand, if it is determined that the leading edge of the document 5 has been detected by the rear sensor 47 (step S125: YES), the CPU 20 recognizes that the switching of the planetary gear 74C from the FB side position to the AFD side position has been completed, and the motor 62 The rotation speed is switched from the switching speed to the reading speed.

  In the case of the present embodiment, as described above, the document 5 is at the ADF reading start position RP before the switching from the switching speed to the reading speed is completed, that is, during the switching from the switching speed to the reading speed. To reach. Therefore, the CPU 20 starts reading the document 5 using the correction data for the switching speed during switching from the switching speed to the reading speed (step S130: an example of the reading process and the starting process). Specifically, the CPU 20 corrects the read data read by the reading unit 30 using the correction data for switching speed, and generates switching speed image data corresponding to a resolution of 1200 dpi (an example of a setting value for switching speed). create. Then, the created switching speed image data is stored in, for example, the RAM 22.

  Next, the switching speed is reduced through during document reading, that is, the rotation of the motor 62 is stopped, and the conveyance of the document 5 is stopped. Then, the rotation of the motor 62 is switched from the switching speed to the reading speed (step S132: an example of a first speed switching process). Next, the CPU 20 starts reading the document 5 using the correction data for the reading speed (step S135: an example of reading processing). Specifically, the CPU 20 corrects the read data read by the reading unit 30 using the correction data for the reading speed, and reads the reading speed image data corresponding to the resolution of 600 dpi (an example of a setting value for the reading speed). create. Then, the created reading speed image data is stored in, for example, the RAM 22.

  Next, the CPU 20 determines whether or not the rear end of the document 5 is detected by the rear sensor 47 with the motor 62 rotated in the Y direction at the reading speed (step S140). When the rear sensor 47 determines that the trailing edge of the document 5 is not detected (step S140: NO), the conveyance and reading of the document at the reading speed are continued. On the other hand, when it is determined that the rear end of the document 5 is detected by the rear sensor 47 (step S140: YES), the CPU 20 reads and generates the switching speed of the document 5 read data at the switching speed before the motor speed switching. Image data is converted into reading speed image data. Specifically, the CPU 20 converts the switching speed image data created based on at least one of the resolution and the number of colors for the switching speed into the reading speed image data based on at least one of the resolution colors for the reading speed. Conversion is performed (step S142: an example of conversion processing). Here, the data conversion is performed for the following reason.

  That is, when the rotation speed of the motor 62 changes, the conveyance speed of the conveyance roller 44 changes, and the reading speed of the document 5 changes accordingly. Usually, the reading speed of the document 5 is set corresponding to the reading resolution of the document 5. Therefore, when the reading speed of the document 5 is not a predetermined reading speed, the reading resolution is not a predetermined resolution. For example, as described above, when the resolution at the reading speed is set to 600 dpi and the resolution at the switching speed is set to 1200 dpi, in order to obtain the read image data with the user-set resolution, the resolution is 1200 dpi. It is necessary to convert the created switching speed image data that has been read into read image data that has been created with a resolution of 600 dpi. Data conversion in this case is performed, for example, by thinning out a predetermined amount of data among the switching speed data.

  Next, the CPU 20 determines whether or not a subsequent document has been detected by the front sensor 49 (step S145). If it is determined that the subsequent document has not been detected (step S145: NO), the ADF reading process is terminated. On the other hand, if it is determined that the subsequent document has been detected (step S145: YES), the CPU 20 drives the transport roller 44 at the reading speed to transport the document 5 (step S155).

  Next, the CPU 20 determines whether or not a jam determination time has elapsed (step S160: an example of an empty feeding determination process). If it is determined that the jam determination time has elapsed (step S160: YES), a jam error is displayed on the display unit 12, for example (step S165), and the ADF reading process is terminated.

  On the other hand, if it is determined that the jam determination time has not elapsed (step S160: NO), it is determined whether the rear sensor 47 has detected the leading edge of the succeeding document 5 (step S170: an example of an empty feed determination process). In the jam determination according to the present embodiment, the CPU 20 skips the subsequent document when the leading edge of the subsequent document 5 is not detected by the rear sensor 47 within a predetermined time (an example of a jam determination time) after operating the conveyance unit. If the rear sensor 47 detects the leading edge of the succeeding document within a predetermined time after operating the conveyance unit, it is determined that the succeeding document is not idle.

  When it is determined that the leading edge of the subsequent document 5 has been detected by the rear sensor 47 (step S170: YES), the CPU 20 drives the conveyance roller 44 at the reading speed and conveys the document 5 at the reading speed, similarly to step S135. The original 5 is read by the reading unit 30 using the correction data for use (step S175). Here, the process of step S175 is an example of a subsequent reading process for causing the reading unit to read the subsequent document 5 conveyed at the reading speed.

  Next, the CPU 20 determines whether or not the rear sensor 47 has detected the trailing edge of the succeeding document 5 (step S180). If the CPU 20 determines that the rear end of the document 5 is not detected by the rear sensor 47 (step S180: NO), the CPU 20 continues to convey and read the subsequent document 5. On the other hand, if the rear sensor 47 determines that the trailing edge of the succeeding document 5 has been detected (step S180: YES), the CPU 20 returns to the process of step S145, and after step S145 is completed until all the documents 5 have been read. Repeat the process.

5. Effects of First Embodiment As described above, the CPU 20 performs a detection process in which the rear sensor 47 detects the document 5 while rotating the motor 62 in the Y direction for switching the planetary gear 74C from the FB side position to the AFD side position. Is configured to run. In order for the rear sensor 47 to detect the document 5, the planetary gear 74 </ b> C is switched to the AFD side position, and the power from the motor 62 is transmitted to the transport units 44 and 44 </ b> A via the transport unit side transmission gear 73. The power transmission needs to be continued for a predetermined time. Therefore, when the planetary gear 74C is switched from the FB side position to the AFD side position, even if the number of driving steps varies due to detection of the document 5 by the rear sensor 47 provided in the conveyance path, It can be reliably detected that the planetary gear 74C has been switched to the ADF side position.

  Further, when there is a document reading request and the document 5 is detected in the detection process (step S125), the CPU 20 causes the reading unit 30 to start reading the document 5. Thereby, since the document reading can be started based on the timing at which the document 5 is detected by the rear sensor 47, the document reading can be started without being affected by the error of the motor drive control when the planetary gear 74C is switched. For this reason, it is possible to suppress document reading defects accompanying the switching operation of the planetary gear 74C.

  When the distance from the document detection position of the rear sensor 47 to the ADF reading position RP is relatively short, the rotational speed of the motor 62 reaches the reading speed depending on how fast the reading speed, which is the rotational speed of the motor 62, is. In some cases, the document 5 may reach the ADF reading position RP before. In this case, if the reading unit 30 is caused to read the image of the document 5 after reaching the reading speed, the read image until the reading speed is reached is lost. However, according to the present embodiment, even when the document 5 reaches the ADF reading position RP before the rotational speed of the motor 62 reaches the reading speed, the document 5 can be read, and thereby the image can be read. Can be prevented from being lost.

  Further, when the rotation speed of the motor 62 is changed from the switching speed to the reading speed, the conveyance of the document 5 is stopped. Therefore, compared with the case where the conveyance of the document 5 is not stopped, the read document 5 can be conveyed more stably when the rotation speed of the motor 62 is switched. That is, if the rotation speed of the motor 62 is switched while the document 5 is being transported, the document transport speed will change during the transport of the document 5, which may cause disturbance in the transport of the document 5. However, by stopping the conveyance of the document 5 and switching the rotation speed of the motor 62, it is possible to avoid such a possibility of the conveyance disorder of the document 5. However, the present invention is not limited to this, and the rotation speed of the motor 62 is switched from the switching speed to the reading speed without stopping the conveyance of the document 5, that is, without stopping the rotation of the motor 62. Also good.

<Embodiment 2>
Next, Embodiment 2 will be described with reference to FIG. Only the ADF reading process is different from the first embodiment. For this reason, the same components as those in the first embodiment are denoted by the same reference numerals, and the same processing is denoted by the same step number, and description thereof is omitted. Further, only differences from the ADF reading process of the first embodiment will be described, and a description of overlapping processes will be omitted.

  In the second embodiment, it is assumed that “the distance from the document detection position of the rear sensor 47 to the ADF reading start position RP” is longer than “the switching speed through-down distance + the reading speed through-up distance”. That is, in the second embodiment, the distance from the document detection position of the rear sensor 47 to the ADF reading start position RP is relatively long, and the rotation speed of the motor 62 is switched from the switching speed to the reading speed. It is assumed that the process is completed before reaching the RP. Therefore, in the second embodiment, the original 5 is read only under the reading speed, and the original 5 is not read under the switching speed.

  In other words, in the second embodiment, the CPU 20 changes the rotation speed of the motor 62 from the switching speed for switching the switching gear to the switching speed before the start processing for causing the reading unit 30 to start reading the document 5. The reading speed for reading 5 is switched.

  Therefore, in the second embodiment, as shown in FIG. 7, unlike the first embodiment, the CPU 20 acquires only the setting value for the reading speed (step S100A). For example, when a resolution of 600 dpi is set by the user from the operation unit 11, the CPU 20 acquires a resolution of 600 dpi from the operation unit 11. Further, correction data for switching speed is not acquired.

  Next, when it is determined that the leading edge of the document 5 is detected by the rear sensor 47 (step S125: YES), the CPU 20 recognizes that the switching of the planetary gear 74C from the FB side position to the AFD side position has been completed, and the motor 62 Is stopped, and the conveyance of the document 5 is stopped (step S205). Then, the rotation speed of the motor 62 is switched from the switching speed to the reading speed (step S210: an example of the second speed switching process).

Then, the CPU 20 starts reading the document 5 using the correction data for the reading speed while conveying the document 5 under the reading speed of the motor 62 (step S215: an example of the post-switching reading process). Specifically, the CPU 20 corrects the read data read by the reading unit 30 using the correction data for the reading speed, and, for example, a reading speed image corresponding to a resolution of 600 dpi (an example of a setting value for the reading speed). Create data. Then, the created reading speed image data is stored in, for example, the RAM 22.
Next, the CPU 20 performs the processing from step S140 to step S180 as in the first embodiment.

6). Effects of Second Embodiment Since the document 5 is read at the reading speed that is the rotation speed of the motor 62, it is not necessary to perform the data conversion process associated with the rotation speed change as shown in step S142 of FIG. Therefore, when the motor 62 is shared for ADF reading (conveyance reading) and FB reading (moving reading), the rotation speed of the motor 62 is set to the reading speed for reading the document 5 when reading the document according to ADF reading. The document 5 can be read at a document reading speed suitable for reading the document 5.

<Embodiment 3>
Next, Embodiment 3 will be described with reference to FIG. Only the ADF reading process is different from the first embodiment. For this reason, the same components as those in the first embodiment are denoted by the same reference numerals, and the same processing is denoted by the same step number, and description thereof is omitted.

  In the third embodiment, the first document 5 is read at the switching speed, and the second document 5 is read at the reading speed. Therefore, when the CPU 20 determines that the front end of the document 5 is detected by the rear sensor 47 (step S125: YES), the CPU 20 recognizes that the switching of the planetary gear 74C from the FB side position to the AFD side position is completed. Then, the CPU 20 reads the document 5 using the correction data for the switching speed while conveying the document 5 under the switching speed of the motor 62 (step S305: an example of a pre-switching reading process). Specifically, the CPU 20 corrects the read data read by the reading unit 30 using the correction data for switching speed, and, for example, a switching speed image corresponding to a resolution of 1200 dpi (an example of a setting value for switching speed). Create data. Then, the created switching speed image data is stored in, for example, the RAM 22.

  If the CPU 20 determines that the rear end of the document 5 has been detected by the rear sensor 47 (step S140: YES), the CPU 20 reads all the created switching speed image data in the same manner as in step S142. (Step S142A: an example of conversion processing). Specifically, the CPU 20 performs data conversion from switching speed image data created based on the resolution and / or number of colors for switching speed to reading speed image data based on the resolution and / or number of colors for reading speed. Do.

  If the CPU 20 determines that the subsequent document has been detected by the front sensor 49 (step S145: YES), the CPU 20 switches the rotation speed of the motor 62 from the switching speed to the reading speed (step S310). The conveyance roller 44 is driven to convey the document 5 (step S155). Here, the process of step S310 and step S155 is an example of a subsequent conveyance process. Next, the CPU 20 performs the processing from step S160 to step S180 as in the first embodiment.

7). Effects of Embodiment 3 Normally, when the planetary gear 74C is switched from the FB side position to the AFD side position at the motor rotation speed (reading speed) when performing ADF reading (conveyance reading), the torque is insufficient. The rotational speed needs to be reduced to a predetermined switching speed. Therefore, on the contrary, when the switching of the planetary gear 74C is completed and ADF reading is performed, it is necessary to change the motor rotation speed from the switching speed to the reading speed. At this time, if the motor rotation speed is changed while the document is being conveyed, there is a risk that the image quality will be lowered due to the change in the motor rotation speed. However, by reading the first document 5 conveyed at the switching speed at the switching speed, it is possible to avoid the possibility of a decrease in image quality due to a change in the motor rotation speed. it can.

  At that time, when reading a plurality of documents 5, only the first document is read at the switching speed, and the second and subsequent documents are read at the reading speed. Therefore, the number of originals that need to be subjected to image data conversion processing associated with the rotation speed change can be minimized. Thereby, it is possible to reduce the time required for the image data conversion process, and hence the reading time. Note that, when reading a plurality of documents 5, switching the rotation speed of the motor 62 in the second document 5 is not limited. For example, the rotation speed of the motor 62 may be switched in the third document 5.

  In the case of the first document 5, the motor 62 is driven at the switching speed. Therefore, if the friction of the document 5 is strong, it may take more time than necessary to feed the document 5 by the feed roller 44A. It is done. In this case, a predetermined feeding time elapses, and the fact that the paper is not actually fed is erroneously detected as idle feeding. However, in the case of the first original 5, the pre-feed determination process (steps S160 and S170) is not performed, so that erroneous detection of the pre-feed can be avoided. Furthermore, in the second and subsequent sheets, it is possible to detect air transport as usual.

  Note that the timing for switching the rotation speed of the motor 62 in the second document 5 is not limited to step S310 after step S145. For example, it may be after step S170. Further, when the rotation speed is switched, the conveyance of the second document 5 may be stopped. That is, the rotation of the motor 62 may be temporarily stopped.

<Embodiment 4>
Next, a fourth embodiment will be described with reference to FIG. Only the ADF reading process is different from the first to third embodiments. Therefore, the same components as those in the first to third embodiments are denoted by the same reference numerals, and the same processing is denoted by the same step number, and description thereof is omitted. Further, only differences from the ADF reading process of the first to third embodiments will be described, and the description of the overlapping processes will be omitted.

  In the fourth embodiment, when the reading range (user set value) is set by the user, the timing for switching the rotation speed of the motor 62 from the switching speed to the reading speed is determined according to the reading range.

  Therefore, in the fourth embodiment, as illustrated in FIG. 9, the CPU 20 first determines whether or not the reading range has been specified by the user, for example, via the operation unit 11. The designated reading range is acquired (step S405). If the rear sensor 47 detects the leading edge of the document 5 (step S125: YES), can the CPU 20 switch the speed of the motor 62 until the designated reading range on the document reaches the ADF reading position RP? It is determined whether or not (step S410: an example of a switching determination process).

  This determination is made, for example, by comparing a predetermined time required for speed switching with a time for the leading end of the reading range on the document in the document transport direction (sub-scanning direction) to reach the ADF reading position RP. The time for the leading end of the reading range to reach the ADF reading position RP depends on, for example, the conveyance speed of the document 5, the distance between the rear sensor 47 and the ADF reading position RP, the distance in the document conveying direction from the leading end of the document 5 to the reading range, and the like. Calculated.

  When it is determined that the speed of the motor 62 can be switched before the reading range reaches the ADF reading position RP (step S410: YES), the speed switching process from step S205 is performed as in the second embodiment. That is, once the document conveyance is stopped (step S205), the speed of the motor 62 is switched (step S210). Thereafter, the original reading process (step S215) and the processes from step S145 to step S180 shown in FIG. 8 are performed. At that time, the process of step S310 is omitted.

  On the other hand, when it is determined that the speed switching of the motor 62 is not possible before the reading range reaches the ADF reading position RP (step S410: NO), the setting value and the correction data for the switching speed are acquired (step S415). Next, similarly to the third embodiment, the processing from step S305 is performed. That is, the speed switching of the motor 62 is not performed on the first document 5 but before the second document 5 is conveyed (see step S310). Then, the process from step S145 to step S180 shown in FIG. 8 is performed.

  In addition, in the switching determination process (step S410), the CPU 20 determines that the speed switching process (step S210) is executed outside the reading range received by the operation unit 11 (accepting unit). It is determined not to execute the speed switching process within the accepted reading range.

8). Effects of Embodiment 4 By executing the speed switching process outside the reading range, it is possible to suppress a decrease in image quality associated with the switching process when the speed switching process is executed within the reading range.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.

  (1) In each of the above embodiments, as the image reading device 3, an example of an image reading device that reads and conveys the original document 5 from the upper side when reading the original document 5 is shown, but is not limited thereto. Absent. The present invention can also be applied to an image reading apparatus that reads and conveys a document 5 from below when the document 5 is read. In the case of this method, the conveyance path between the front sensor and the rear sensor can usually be formed so as to be substantially straight. Therefore, a jam is caused between the front sensor and the rear sensor as compared with the method of reading the document 5 from the upper side to the lower side. Is unlikely to occur. For this reason, the method of reading the document 5 by conveying it from the lower side to the upper side can be said to be more suitable for not detecting jam on the first document.

  (2) In each of the above embodiments, the example in which the planetary gear 74C in the planetary gear mechanism 74 is used as the switching gear is shown, but the present invention is not limited to this. As a switching gear, a carriage side position (FB side position) that connects the motor side transmission gear 71 and the carriage side transmission gear 72, and a conveyance unit side position that connects the motor side transmission gear 71 and the conveyance unit side transmission gear 73 ( Other known configurations that switch to the ADF side position) may be used.

DESCRIPTION OF SYMBOLS 3 ... Image reading apparatus, 5 ... Document, 20 ... CPU, 30 ... Reading part, 34 ... Carriage, 42 ... Document tray, 43 ... Conveyance path, 44 ... Conveyance roller, 44A ... Paper feed roller, 45 ... Discharge roller, 47 ... Rear sensor, 49 ... Front sensor, 55 ... Home position detection mark, 55A ... White tape, 55B ... Black tape, 62 ... Motor, 71 ... Motor side transmission gear, 72 ... Carriage side transmission gear, 73 ... Conveyer side Transmission gear, 74C ... Planetary gear

Claims (13)

A reading unit for reading an image of a document;
A transport section for transporting a document;
A conveyance path through which the document is conveyed by the conveyance unit;
A sensor provided in the conveyance path for detecting the document;
A carriage that holds the reading unit and moves in a predetermined direction;
A motor,
A motor-side transmission gear for transmitting power supplied by the motor;
A conveyance unit-side transmission gear that transmits the power to the conveyance unit at the time of conveyance reading for reading a document conveyed by the conveyance unit;
A carriage-side transmission gear that transmits the power to the carriage when moving and reading the image by moving the carriage;
During the conveyance reading, in the state where the carriage is in the conveyance reading position which is the document reading position, the conveyance unit side transmission gear is connected at the conveyance unit side position connecting the motor side transmission gear and the conveyance unit side transmission gear. A switching gear that switches to engage with the carriage-side transmission gear at a carriage-side position that connects the motor-side transmission gear and the carriage-side transmission gear during the movement reading;
A control unit,
The controller is
An image reading apparatus configured to execute a detection process for causing the sensor to detect a document while rotating the motor in a direction to switch the switching gear from the carriage side position to the conveyance unit side position. . The image reading apparatus according to claim 1,
A request receiving unit for receiving a document reading request, wherein the sensor is provided on the upstream side of the document conveyance with respect to the reading unit in the conveyance path;
The controller is
An image reading apparatus configured to execute a start process for causing the reading unit to start reading a document when the request receiving unit receives a document reading request and a document is detected in the detection process. The image reading apparatus according to claim 2,
The controller is
In the start process, based on a switching speed that is a rotational speed of the motor for switching the switching gear, the reading unit reads a document,
A first speed at which the rotation speed of the motor is switched from the switching speed to a reading speed for reading a document that is different from the switching speed during the reading of the document by the reading unit under the switching speed. Switching process,
An image reading apparatus configured to execute post-switching reading processing for causing the reading unit to read the document based on the reading speed. The image reading apparatus according to claim 2,
The controller is
A second speed switching process for switching the rotation speed of the motor from a switching speed for switching the switching gear to a reading speed for reading a document, which is different from the switching speed, before the start process;
An image reading apparatus configured to execute post-switching reading processing for causing the reading unit to read the document based on the reading speed. The image reading apparatus according to claim 3 or 4,
The controller is
An image reading apparatus configured to execute stop processing for stopping transport of a document transported under the switching speed of the motor before the speed switching processing. The image reading apparatus according to claim 2,
The controller is
In the detection process, from the time when the leading edge of the document is detected until the trailing edge of the document is detected, the conveying unit is controlled based on a switching speed that is a rotation speed of the motor for switching the switching gear. A conveyance process for conveying the document;
A pre-switching reading process for causing the reading unit to read the document conveyed under the switching speed;
The switching speed is switched to a reading speed that is different from the switching speed and is a rotational speed of the motor for reading a document. Based on the reading speed, a succeeding document that follows the document is transferred to the transport unit. Subsequent transport processing to transport,
An image reading apparatus configured to further execute a subsequent reading process for causing the reading unit to read the subsequent document conveyed at the reading speed. The image reading apparatus according to claim 3 or 6,
The controller is
An image reading apparatus configured to execute an acquisition process for acquiring a setting value for a switching speed for reading the document based on the switching speed before the reading process. The image reading apparatus according to claim 7.
A storage unit for storing image data obtained by the reading process;
The controller is
In the reading process, the switching speed image data corresponding to the setting value for switching speed is created, and the created switching speed image data is stored in the storage unit,
A conversion process for converting the switching speed image data stored in the storage unit into reading speed image data created according to a reading speed setting value for reading the document based on the reading speed is executed. An image reading apparatus configured to do the above. The image reading apparatus according to claim 8.
The switching speed setting value includes a resolution corresponding to the switching speed,
The image reading apparatus, wherein the setting value for reading speed includes a resolution corresponding to the reading speed. The image reading apparatus according to claim 8 or 9,
The setting value for the switching speed includes the number of colors corresponding to the switching speed,
The image reading apparatus, wherein the setting value for reading speed includes the number of colors corresponding to the reading speed. In the image reading device according to any one of claims 6 to 10,
The manuscript includes a plurality of manuscripts,
The original read in the reading process is a first original of the plurality of originals, and the subsequent original read in the subsequent reading process is a second or later of the plurality of originals. An image reading apparatus that is an original document. The image reading apparatus according to claim 2,
A designation receiving unit that accepts designation of a reading range, which is a range in which the user causes the reading unit to read a document;
The controller is
When the leading edge of the document is detected in the detection process, a speed switching process for switching the rotation speed of the motor from a switching speed for switching the switching gear to a reading speed for reading a document that is different from the switching speed. Is configured to execute a switching determination process for determining whether or not to execute
In the switching determination process, it is determined that the speed switching process is executed outside the reading range accepted by the designation receiving unit, and the speed switching process is not executed within the reading range accepted by the designation receiving unit. An image reading apparatus that makes a determination. The image reading apparatus according to any one of claims 1 to 12,
A document tray on which a first document and a subsequent document following the first document are placed;
The controller is
If the leading edge of the succeeding document is not detected by the sensor within a predetermined time after operating the conveying unit, it is determined that the succeeding document is idle.
When the leading edge of the succeeding document is detected by the sensor within a predetermined time after the operation of the transport unit, it is configured to execute an empty feeding determination process for determining that the succeeding document is not idle. Image reading device.

Images