JP5451218B2 - Image reading apparatus, control method therefor, and sheet processing apparatus - Google Patents

Description

  The present invention relates to an image reading apparatus, a control method therefor, and a sheet processing apparatus.

  2. Description of the Related Art Conventionally, as an image reading apparatus, an image reading apparatus that reads an image by synchronizing a document conveyance speed and an image reading cycle is known.

  In such an image reading apparatus that reads an image by synchronizing the document conveyance speed and the image reading cycle, the motor may reversely rotate when the conveyance of the document is stopped. When the motor rotates in the reverse direction in this way, a phenomenon occurs in which a part of the original is read redundantly because the image is read by synchronizing the rotation of the motor and the image reading cycle. Such a reverse rotation phenomenon of the motor occurs due to, for example, an elastic component of the original document itself, an elastic component of the original document conveyance unit, mechanical distortion, and play. In particular, such a problem becomes conspicuous when a document carrying load is large and the carrying is stopped halfway.

  Therefore, in order to avoid such reverse rotation phenomenon of the motor, a one-way clutch that prohibits reverse rotation (Patent Document 1), a mechanism that always repeats forward / reverse rotation of the motor and keeps the motor at a fixed position (Patent Document) 2) When the image reading operation is interrupted, the original is intentionally retracted to a predetermined position in preparation for resumption of the image reading operation, and when the restart is instructed, the original is conveyed from the predetermined position to the image reading stop position. A mechanism for resuming image reading (Patent Document 3) has been proposed.

Japanese Patent No. 3666950 specification JP 2005-333377 A JP 2004-032545 A

However, when the one-way clutch described in Patent Document 1 is adopted, the cost of the apparatus is increased, and an installation space is required for mounting the members constituting the one-way clutch. Further, in the invention described in Patent Documents 2 and 3, because it uses a reverse rotation driving circuit for intentionally reversing the motor, not only installation space becomes necessary, the reverse rotation driving circuit Electric power is required for operation.

  The above-described problem does not occur only in the image reading apparatus. For example, an apparatus that affects a predetermined process due to reverse rotation of a motor or the like may similarly occur.

  Therefore, in view of the circumstances described above, the present invention provides an image reading apparatus that can effectively reduce the size and power consumption of the apparatus while effectively preventing duplicate reading of an original, a control method thereof, and sheet processing. An object is to provide an apparatus. Other issues can be understood throughout the specification.

The image reading apparatus of the present invention is, for example,
Separation feeding means for separating and feeding the documents on the tray one by one;
A conveying means provided on the downstream side in the feeding direction with respect to the separating and feeding means, and for conveying a document by a rotating body;
Image reading means for reading an image of the document conveyed by the conveying means;
Driving means for rotationally driving the rotating body;
Detection means for detecting a rotation direction and a rotation distance of the rotating body;
Image reading control means for controlling the image reading means so as to read an image of the document based on a positive rotation distance detected by the detection means when the rotating body rotates in the normal rotation direction;
The image reading control means is detected by the detection means when a force in a direction opposite to the document feeding direction from the separation feeding means acts on the document during document transportation and the rotating body rotates in the reverse direction. based on the reverse rotation distance due to the reverse rotation of said drive means, characterized by being adapted to control the image reading means to not read duplicate image of the original document.

  According to the present invention, it is possible to realize downsizing and power saving of an apparatus while effectively preventing duplicate reading of an original, and to reduce costs such as apparatus cost and running cost. Can do. Furthermore, since it is not necessary to provide a one-way clutch or a reverse rotation drive circuit separately as in the conventional apparatus, the number of parts can be reduced and the apparatus cost can be greatly reduced.

1 is a schematic cross-sectional view of an image reading apparatus including a sheet conveying device. FIG. 3 is a block diagram illustrating a control unit that performs document conveyance and reading control according to the first exemplary embodiment. 3 is a schematic diagram of an encoder sensor 203. FIG. 3 is a flowchart illustrating a method for controlling the image reading apparatus according to the first exemplary embodiment. 6 is a block diagram illustrating a control unit that performs document conveyance and reading control according to Embodiment 2. FIG. 6 is a flowchart illustrating a method for controlling the image reading apparatus according to the second embodiment. FIG. 10 is a block diagram illustrating a control unit that performs document conveyance and reading control according to a third embodiment. 10 is a flowchart illustrating a method for controlling the image reading apparatus according to the third exemplary embodiment.

[Example 1]
FIG. 1 is a schematic cross-sectional view of an image reading apparatus including a sheet conveying device. In the image reading apparatus 100, a paper feed tray 2 on which documents (sheets) are stacked is supported so as to be openable and closable with respect to the apparatus main body 1A via a hinge portion 2a. The sheet feed tray 2 covers the document feed port 13 in the closed state (broken line in FIG. 1), and the document is stacked on the stacking surface 2b in the opened state (solid line in FIG. 1).

  A plurality of documents stacked on the sheet feed tray 2 are separated and fed one by one from the lowermost document to the conveyance path by the feed roller 4 and the separation pad 5. The document fed to the conveyance path is conveyed downstream by the conveyance roller pair 6. Further, the original is scanned on both the front and back surfaces by the reading sensors 8 and 9, and then is discharged out of the apparatus by the conveying roller pair 7.

  In this embodiment, it is preferable to use a motor that can be driven with low power as the driving unit of the conveying unit that conveys the document. For example, in the present embodiment, a DC motor is used to simultaneously drive conveying means including rotating members such as the feed roller 4, the conveying roller pair 6, and the conveying roller pair 7 described above. Thus, the DC motor is an example of a driving unit that rotationally drives the rotating body.

  Although not shown, the power supply unit provided in such an image reading apparatus may be a circuit that converts an AC voltage supplied from a commercial power source into a DC voltage, or may be realized by an AC adapter. However, a power supply circuit based on so-called USB bus power may be used. For example, in this embodiment, power is supplied to the power supply unit by USB bus power.

  That is, the image reading apparatus of the present embodiment is connected to an information processing apparatus such as a computer with a USB cable, and power is supplied from the information processing apparatus. Therefore, the power source of the image reading apparatus of the present embodiment is It depends on the power supply capability of the information processing device.

  For example, if the information processing device is connected to a commercial power source, power supply can be secured stably to some extent. However, if the information processing device is battery-driven, such as a notebook computer, sufficient power The supply may not be ensured stably for a long time. Although details will be described later in this embodiment, low-power driving is realized by various devices in addition to the above-described DC motor adoption.

  Here, the image reading apparatus 100 of the present embodiment is connected to the information processing apparatus, and the read image is temporarily stored in a buffer memory (hereinafter referred to as a buffer), and sequentially transmitted from the buffer to the information processing apparatus. It is configured to

  For this reason, the image reading apparatus 100 according to the present embodiment is configured to suspend reading of an image until the buffer is full when the read image is full. That is, when the buffer becomes full, the conveyance of the document is temporarily stopped. Even if the motor is de-energized, the conveyance of the document is temporarily continued toward the downstream side of the conveyance path due to inertia or inertia, but the document is conveyed toward the downstream side in this way. Then, the image reading is substantially continued. Therefore, even if image reading is interrupted, image discontinuity does not occur as long as the motor is rotating forward.

  By the way, reverse rotation may occur after the forward rotation of the motor is completed. This occurs, for example, due to an elastic component of the original document itself, an elastic component of the original document conveyance unit, mechanical distortion, play, and the like. In the structure of the present embodiment, for example, the contact surfaces of the feed roller 4, the separation pad 5, the transport roller pair 6, and the transport roller pair 7 with the document are made of an elastic body such as rubber. It is. Since a part of the elastic force of the elastic body acts in the direction of pushing back the document, the DC motor that drives the conveying means such as the feed roller 4, the conveying roller pair 6, and the conveying roller pair 7 rotates in the reverse direction. The reverse rotation amount (reverse rotation distance) is so small that it is difficult to confirm visually, but it appears clearly as a line overlap in the read image of the document. Therefore, in this embodiment, when reverse rotation occurs, the reverse rotation distance is measured and held, and when reading is resumed, the image is resumed after the motor rotates forward by the reverse rotation distance. It is characterized by doing.

  FIG. 2 is a block diagram illustrating a control unit that performs document conveyance and reading control according to the first embodiment. The DC motor 201 is an example of a driving unit for driving a conveying unit that conveys a document. The DC motor 201 is controlled by the drive control unit 202. The drive control unit 202 is a rotation control circuit that can rotate the DC motor 201 only in one direction (forward rotation direction) from the viewpoint of cost reduction. That is, the drive control unit 202 does not include an energization circuit for intentionally rotating the DC motor 201 in the reverse direction. The drive control unit 202 is an example of a drive control unit that controls the drive unit. Thereby, the electric power used when reversely rotating the DC motor 201 becomes unnecessary, and power saving can be achieved. In addition, it is possible to save space in circuit design, and as a result, it contributes to downsizing of the apparatus.

  In this embodiment, an encoder sensor 203 is connected to the DC motor 201. Specifically, the encoder sensor 203 is attached to the rotating shaft of the DC motor 201 and has a function of generating an encoder pulse corresponding to the rotating state of the DC motor 201 and outputting the encoder pulse to the driving state detecting unit 204. Yes. In this way, the encoder sensor 203 is attached to the rotating shaft of the DC motor 201 that simultaneously drives the conveying means such as the feed roller 4, the conveying roller pair 6, and the conveying roller pair 7. Therefore, the encoder pulse output from the encoder sensor 203 reflects the rotation state (rotation direction and rotation distance) of the rotating body such as the feed roller 4 via the DC motor 201.

  FIG. 3 is a schematic diagram of the encoder sensor 203. The slit plate 302 rotates in synchronization with the rotation of the DC motor 201. An encoder pulse is output from the encoder 301 in conjunction with whether the slit provided in the slit plate 302 blocks or transmits the light path of the light receiving element from the light emitting element in the encoder 301. The drive state detection unit 204 detects the rotation state of the DC motor 201 from the cycle and phase relationship of the encoder pulse. That is, the drive state detection unit 204 is an example of a detection unit that detects the rotation direction and the rotation distance of the rotating body using the encoder sensor 203 described above.

  Further, the drive state detection unit 204 supplies rotation information such as the detected rotation direction and rotation distance to the TG 205. TG is an abbreviation for timing generator. The rotation information corresponds to, for example, the number of pulses of the pulse signal. The drive state detection unit 204 includes a holding unit 211 that holds the reverse rotation distance. The holding unit 211 functions as a holding unit that holds the reverse rotation distance associated with the reverse rotation of the drive unit when the rotation direction of the drive unit changes from the normal rotation direction to the reverse rotation direction. Here, “holding the reverse rotation distance” means, for example, storing information on the reverse rotation distance associated with the reverse rotation. In this embodiment, the holding unit 211 is an information storage unit (memory). The TG 205 is an example of a timing signal generating unit that generates a timing signal indicating the start of reading one line for each predetermined rotation distance and supplies the timing signal to the image reading unit.

  The TG 205 transmits a one-line reading start timing pulse to the CIS sensor 206 at every fixed rotation distance based on the rotation information. For example, the TG 205 counts the number of pulses of the pulse signal supplied as rotation information from the driving state detection unit 204, and transmits a one-line reading start timing pulse when the count value reaches a predetermined number of pulses. The CIS sensor 206 reads the conveyed document based on the pulse supplied from the TG 205. The CIS sensor 206 is an example of an image reading unit. The CIS sensor 206 is an abbreviation for contact image sensor.

  Here, in the present embodiment, when the DC motor 201 rotates in the reverse direction when the reading of the document is stopped, the driving state detection unit 204 described above indicates the rotation information such as the rotation direction and the rotation distance detected at that time. Functions to cease supply to That is, when the DC motor 201 rotates in the reverse direction, the CIS sensor 206 does not receive a timing pulse signal corresponding to the reverse rotation amount (reverse rotation distance) corresponding to the reverse rotation amount, and performs image reading. There is nothing.

  Then, when the reading of the document is resumed from such an interrupted state of the image reading, that is, when the DC motor 201 shifts from the reverse rotation position to the normal rotation, the driving state detection unit 204 performs DC rotation. Control is performed so that the reading of the CIS sensor 206 is resumed from the time when the reverse rotation distance at the reverse rotation position of the motor 201 is exceeded. Note that such a driving state detection unit 204 controls the image reading unit so that the image reading unit does not redundantly read the original image based on the reverse rotation distance accompanying the reverse rotation of the rotating body detected by the detection unit. It is an example of a means.

  As described above, in the image reading apparatus of this embodiment, when the DC motor 201 rotates in the reverse direction, the CIS sensor 206 does not read the image in synchronization with the reverse rotation. Reading can be effectively prevented.

  And since it is not necessary to provide a one-way clutch and a reverse rotation circuit like the conventional apparatus, space saving can be achieved and size reduction of an apparatus can be implement | achieved. Further, since power for driving the reverse rotation circuit is unnecessary, power saving can be realized.

  Furthermore, unlike the prior art, it is not necessary to provide a one-way clutch or a reverse rotation circuit, so the number of parts can be reduced and the apparatus cost can be greatly reduced, and the running cost and the like can be reduced. be able to.

  In the present embodiment, for example, the drive control unit controls the original conveyance force to be temporarily increased from the conveyance force during normal conveyance with respect to the return (restart) operation to the normal rotation after the reverse rotation. It may be. For example, in the case of a document that requires conveyance force such as cardboard such as a business card, there is some waiting time until restart when returning to normal rotation after reverse rotation. For this reason, when such originals such as thick paper are rotated forward after reverse rotation, the document transport force (specifically, the transport speed, etc.) is temporarily increased to reduce the time required for restart. You can also. The thickness of the document can be specified by a return amount such as a reverse rotation distance. Of course, it may be detected by an optical sensor, an ultrasonic sensor, or the like arranged separately.

  Here, as described above, the image reading apparatus of this embodiment transfers the image read by the CIS sensor 206 to a PC or the like. Specifically, the CIS sensor 206 outputs an analog image signal to the analog data processing unit 207. The analog data processing unit 207 performs optical black level correction, signal amplitude adjustment, and the like, converts it into a digital image signal, and stores it in the memory 209. The image processing unit 208 reads out the digital image signal from the memory 209, executes image processing, and transfers it to the PC 210.

  FIG. 4 is a flowchart illustrating the control method of the image reading apparatus according to the first embodiment. In step S <b> 401, the drive control unit 202 starts energizing the DC motor 201 when instructed to start document reading by the PC 210. Thereby, the DC motor 201 rotates in the forward rotation direction. An encoder pulse is output from the encoder sensor 203. The drive control unit 202 includes a rotation control circuit that rotates the drive means only in one direction.

In S402, the drive state detection unit 204 detects the rotation direction and the rotation distance from the encoder pulse, and determines whether the rotation direction is the normal rotation direction or the reverse rotation direction. Therefore, the drive state detection unit 204 is an example of a determination unit that determines whether the rotation direction detected by the detection unit is the reverse rotation direction or the normal rotation direction. If it is not the forward rotation direction (that is, if it is the reverse rotation direction), the process proceeds to S403. The drive control unit 202 temporarily stops the reading operation halfway so that the image data size does not exceed the storable capacity of the memory 209 during image reading. At this time, the drive control unit 202 completely cuts off the power supply to the DC motor 201 to prevent wasteful power consumption. In the first embodiment, since a mechanism member such as a one-way clutch is not provided, a reverse rotation phenomenon of the DC motor 201 may occur.

  In step S <b> 403, the driving state detection unit 204 prohibits transmission of rotation information to the TG 205. By prohibiting the transmission of the rotation information from the drive state detection unit 204 to the TG 205, the TG 205 stops transmitting the timing pulse signal to the CIS sensor 206. As described above, the driving state detection unit 204 supplies the information on the rotation distance to the timing signal generation unit if the rotation direction of the driving unit is the normal rotation direction, and the timing signal if the rotation direction of the driving unit is the reverse rotation direction. The supply of the rotational distance information to the generating means is stopped.

In S404, the driving state detection unit 204 detects the reverse rotation distance from the encoder pulse, and holds the reverse rotation distance in the holding unit 211 (register or memory) provided therein. Thereafter, the process returns to S402. Eventually, the holding unit 211 holds the total reverse rotation distance detected between the normal rotation and the reverse rotation until the normal rotation again.

  Note that it is desirable to correct the reverse rotation distance depending on the elastic component, mechanical distortion, backlash, and the like of the document conveying unit. The drive state detection unit 204 corrects the detected reverse rotation distance with a predetermined correction value, and holds the corrected reverse rotation distance in the holding unit 211. The correction value is determined based on the elastic component, mechanical distortion, backlash, and the like of the document conveyance unit. As described above, the drive state detection unit 204 functions as a correction unit that corrects the reverse rotation distance held by the holding unit with a correction value determined based on the accuracy of the mechanical mechanism attached to the drive unit. This correction process is optional.

If the forward rotation direction is determined in S402, the process proceeds to S405. In step S405, the driving state detection unit 204 determines whether the reverse rotation distance held in the internal register or memory exceeds the normal rotation distance (after returning to the normal rotation). . Note that the reverse rotation distance remains zero if no reverse rotation occurs due to the stop of the conveyance. If the normal rotation distance exceeds the reverse rotation distance, reading overlap does not occur, and the process proceeds to S407. As described above, the drive state detection unit 204 holds the rotation distance in the forward rotation direction detected by the detection unit after the rotation direction of the drive unit changes from the reverse rotation direction to the forward rotation direction again. It functions as a reading control means for restarting reading of an image by the image reading means after exceeding the reverse rotation distance.

  In step S407, the driving state detection unit 204 permits transmission of rotation information from the driving state detection unit 204 to the TG 205. Thereby, the drive state detection unit 204 resumes or continues the transmission of the rotation information. In step S408, the drive control unit 202 determines whether image reading has been completed. If not completed, the process returns to S402.

On the other hand, if it is determined in S405 that the normal rotation distance does not exceed the reverse rotation distance, the process proceeds to S406. In step S406, the driving state detection unit 204 prohibits transmission of rotation information. Thereafter, the process returns to S402.

  According to the first embodiment, when reverse rotation occurs, the reading operation of the CIS sensor 206 is stopped by stopping the supply of rotation information. Further, the reverse rotation distance is held, and the reading operation of the CIS sensor 206 is restarted after the normal rotation distance after the normal rotation is resumed exceeds the reverse rotation distance. Therefore, in the first embodiment, it is possible to suppress duplicate reading of a document without providing a one-way clutch or a reverse rotation circuit.

  Further, by correcting the reverse rotation distance using the correction value determined based on the accuracy of the mechanical mechanism attached to the DC motor 201, it is possible to further improve the document reading accuracy.

[Example 2]
In the first embodiment, the method of interrupting the reading of the CIS sensor 206 by stopping the driving state detection unit 204 from supplying the rotation information to the TG 205 has been described. In the second embodiment, a method of interrupting reading of the CIS sensor 206 by stopping the supply of signals from the TG 205 to the CIS sensor 206 will be described.

  FIG. 5 is a block diagram illustrating a control unit that performs document conveyance and reading control according to the second embodiment. Descriptions will be simplified by assigning the same reference numerals to parts common to the first embodiment. It is assumed that the drive state detection unit 504 has all the basic functions of the drive state detection unit 204 described above. Similarly, the TG 505 is assumed to have all the basic functions of the TG 205 described above.

  The drive state detection unit 504 always outputs an encoder pulse as rotation information to the TG 505. When the TG transmission control unit 511 permits TG transmission, the TG 505 transmits a one-line reading start pulse corresponding to the number of encoder pulses to the CIS sensor 206. On the other hand, when the TG transmission control unit 511 prohibits TG transmission, the TG 505 does not output a one-line reading start pulse to the CIS sensor 206. As described above, the TG 505 supplies a timing signal when the rotation direction of the driving unit is the forward rotation direction, and an example of the timing signal generation unit that stops supplying the timing signal when the rotation direction of the driving unit is the reverse rotation direction. It is.

  FIG. 6 is a flowchart illustrating a method for controlling the image reading apparatus according to the second embodiment. S403, S406, and S407 shown in FIG. 4 are replaced with S603, S606, and S607.

  When the drive state detection unit 504 detects reverse rotation in S402, the process proceeds to S603. In step S603, the driving state detection unit 504 notifies the TG transmission control unit 511 that reverse rotation has been detected. The TG transmission control unit 511 recognizes the reverse rotation of the DC motor 201 and switches the TG 505 to the TG transmission prohibited state. As a result, the TG 505 stops transmitting signals to the CIS sensor 206. Thereafter, the process proceeds to S404.

  If it is determined in S405 that the normal rotation distance is equal to or less than the reverse rotation distance, the process proceeds to S606. In step S606, the driving state detection unit 504 notifies the TG transmission control unit 511 that the normal rotation distance is equal to or less than the reverse rotation distance. The TG transmission control unit 511 recognizes that the normal rotation distance is equal to or less than the reverse rotation distance, and continues the TG transmission prohibition state of the TG 505.

  On the other hand, if it is determined in S405 that the forward rotation distance exceeds the reverse rotation distance, the process proceeds to S607. In step S <b> 607, the TG transmission control unit 511 permits the TG 505 to transmit a signal to the CIS sensor 206. As a result, the TG 505 resumes signal transmission to the CIS sensor 206. The CIS sensor 206 resumes image reading.

  Thus, also in Example 2, the same effect as Example 1 can be produced.

Example 3
The third embodiment is an improved invention of the first embodiment. In the third embodiment, a method of shortening the reverse rotation distance by electrically braking the rotation of the DC motor 201 when the DC motor 201 is stopped (so-called short brake) will be described.

  FIG. 7 is a block diagram illustrating a control unit that performs document conveyance and reading control according to the third embodiment. Descriptions will be simplified by assigning the same reference numerals to parts common to the first embodiment. It is assumed that the drive control unit 702 has all the functions of the drive control unit 202 described so far.

  The drive forced stop unit 701 forcibly stops (that is, brakes) the DC motor 201 in accordance with an instruction from the drive control unit 702. For example, the drive forced stop unit 701 brakes (brakes) the rotation of the DC motor 201 by short-circuiting the power supply terminals of the DC motor 201 and setting both terminals to the same potential. This is called a short brake. Since the short brake can be constituted by a simple electric circuit, it is advantageous in terms of cost and space over the mechanical brake. As described above, the drive forced stop unit 701 and the drive control unit 702 are examples of drive control units that forcibly stop (brake) the drive of the drive unit if the rotation direction of the drive unit is the reverse rotation direction.

  FIG. 8 is a flowchart illustrating a method for controlling the image reading apparatus according to the third embodiment. S801 is added between No in S402 and S403 shown in FIG. Further, S802 and S803 are added after S404.

  When the drive state detection unit 204 notifies that the DC motor 201 has rotated in the reverse direction, the drive control unit 702 instructs the drive forced stop unit 701 to forcibly stop the DC motor 201 in S801. Thereby, the drive forced stop unit 701 stops the DC motor 201. Thereafter, S403 and S404 are executed, and the process proceeds to S802.

  In step S <b> 802, the drive state detection unit 204 determines whether the DC motor 201 has completely stopped. When the DC motor 201 is completely stopped, the process proceeds to S803. In step S803, the drive state detection unit 204 notifies the drive control unit 702 that the DC motor 201 has completely stopped. The drive control unit 702 recognizes that the DC motor 201 is completely stopped, and instructs the drive forced stop unit 701 to cancel the forced stop of the DC motor 201. The drive forced stop unit 701 cancels the forced stop state between the terminals of the DC motor 201. Thereafter, the process returns to S402.

  As described above, according to the third embodiment, the reverse rotation distance can be shortened by stopping the rotation of the DC motor 201 when the DC motor 201 is stopped. As a result, the conveyance distance until the document reading is resumed after the conveyance is resumed can also be shortened. Therefore, it is possible to reduce the time required for the normal rotation after the reverse rotation to resume the document reading.

[Other Examples]
In the third embodiment, the improvement of the first embodiment has been described. However, the technical idea of the third embodiment can also be applied to the second embodiment. In this case, S801 is added between Yes in S402 and S603 in FIG. In addition, S802 and S803 are added after S404. Further, the drive control unit 202 in FIG. 5 is replaced with a drive forced stop unit 701 and a drive control unit 702.

  Although the separation pad 5 has been described with reference to FIG. 1, the present invention can also be applied to an image reading apparatus that employs a separation roller instead of the separation pad 5.

  Furthermore, the technical idea of the present invention can be applied to a sheet processing apparatus. The sheet processing apparatus includes a conveying unit that conveys a sheet by a rotating body, a driving unit that drives the conveying unit, a detecting unit that detects a rotation direction and a rotation distance of the rotating body, and the rotating body rotates in a normal rotation direction. To the sheet based on the reverse rotation distance associated with the reverse rotation of the rotating body detected by the detection means, and the sheet processing means for executing a predetermined process on the sheet based on the normal rotation distance detected by the detection means Control means for controlling the sheet processing means so as not to perform the predetermined processing. More specifically, if the rotation direction of the drive unit is a normal rotation direction, a predetermined process is performed on the sheet according to the rotation distance detected by the detection unit, and the rotation direction of the drive unit is a reverse rotation direction. For example, the sheet processing means for interrupting the predetermined processing and the rotation distance in the normal rotation direction detected by the detection means after the rotation direction of the driving means changes from the reverse rotation direction to the normal rotation direction again are held by the holding means. And a control means for restarting the sheet processing of the sheet processing means after exceeding the reverse rotation distance. The sheet processing apparatus includes not only the image reading apparatus 100 described above but also an image forming apparatus such as a printer. Examples of the sheet processing unit include a CIS sensor 206 and an image forming unit.

1A device main body 4 feed roller 5 separation pad 6 transport roller pair 7 transport roller pair 13 paper feed port 100 image reading device 201 DC motor 202 drive control unit 203 encoder sensor 204 drive state detection unit 206 CIS sensor 207 analog data processing unit 209 memory 211 Holding unit 302 Slit plate 511 TG transmission control unit 701 Drive forced stop unit 702 Drive control unit

Claims (11)

Separation feeding means for separating and feeding the documents on the tray one by one;
A conveying means provided on the downstream side in the feeding direction with respect to the separating and feeding means, and for conveying a document by a rotating body;
Image reading means for reading an image of the document conveyed by the conveying means;
Driving means for rotationally driving the rotating body;
Detection means for detecting a rotation direction and a rotation distance of the rotating body;
Image reading control means for controlling the image reading means so as to read an image of the document based on a positive rotation distance detected by the detection means when the rotating body rotates in the normal rotation direction;
The image reading control means is detected by the detection means when a force in a direction opposite to the document feeding direction from the separation feeding means acts on the document during document transportation and the rotating body rotates in the reverse direction. based on the reverse rotation distance due to the reverse rotation of the drive means, the image reading apparatus is characterized in that so as to control the image reading means to not read duplicate image of the original document. Determination means for determining whether the rotation direction detected by the detection means is a reverse rotation direction or a normal rotation direction;
When the rotation direction changes from a normal rotation direction to a reverse rotation direction, further comprising holding means for holding a reverse rotation distance associated with the reverse rotation of the rotating body,
The image reading control unit reads the image of the document according to the normal rotation distance detected by the detection unit if the rotation direction of the rotating body is a normal rotation direction, and if the rotation direction is a reverse rotation direction. Interrupt reading of the image,
The image reading control means has a reverse rotation distance in which a normal rotation distance in the normal rotation direction detected by the detection means after the rotation direction is changed again from the reverse rotation direction to the normal rotation direction is held by the holding means. 2. The image reading apparatus according to claim 1, wherein the image reading unit resumes reading of an image after exceeding the limit.   The image reading apparatus according to claim 1, wherein the image reading control unit stops supplying information on a reverse rotation distance detected by the detecting unit to the image reading unit. The image reading control means includes
Timing signal generating means for generating a timing signal indicating the start of reading of one line for each predetermined rotation distance and supplying the timing signal to the image reading means;
The detecting means supplies the information on the normal rotation distance to the timing signal generating means if the rotating body rotates forward, and the information on the reverse rotating distance to the timing signal generating means if the rotating body rotates reversely. 4. The image reading apparatus according to claim 1, wherein the supply of the image is stopped. 5. The image reading control means includes
Timing signal generating means for generating a timing signal indicating the start of reading of one line for each predetermined rotation distance and supplying the timing signal to the image reading means;
4. The timing signal generation unit supplies the timing signal when the rotating body rotates forward, and stops supplying the timing signal when the rotating body rotates reversely. 5. The image reading apparatus according to claim 1. Drive control means for controlling the drive means;
The drive control means forcibly stops the rotational drive of the rotating body when the detecting means detects that the rotating body is in a reverse rotation state. 2. An image reading apparatus according to item 1. The driving means is a DC motor;
The image reading apparatus according to claim 6, wherein the drive control unit forcibly stops the DC motor by setting the power supply terminals of the DC motor to the same potential.   The correction means which corrects the information on the reverse rotation distance detected by the detection means with a correction value determined based on the accuracy of the mechanical mechanism attached to the drive means. 8. The image reading apparatus according to any one of 7 above.   The image reading apparatus according to claim 1, wherein the driving unit is controlled by a rotation control circuit that rotates the driving unit only in one direction. A detection step of detecting a rotation direction and rotation distance of the rotating body at the time of feeding transportable by rotating body original to be separating and feeding documents one by one from the tray by separating and feeding means,
An image reading step in which an image reading unit reads an image of the document based on the positive rotation distance detected by the detection step when the rotating body rotates in the positive rotation direction;
In the image reading process, the detection process detects that a force in the direction opposite to the document feeding direction from the separation feeding unit acts on the document during the document conveyance and the rotating body rotates in the reverse direction. An image reading method comprising: controlling the image reading unit so as not to read an image of the original document redundantly based on a reverse rotation distance accompanying reverse rotation of the rotating body. Separation feeding means for separating and feeding the documents on the tray one by one;
A conveying means that is provided downstream of the separating and feeding means in the feeding direction and conveys a sheet by a rotating body;
Driving means for driving the conveying means;
Detecting means for detecting a rotation direction and a rotation distance of the rotating body;
Sheet processing means for executing a predetermined process on the sheet based on a positive rotation distance detected by the detection means when the rotating body rotates in the forward rotation direction;
While the document is being conveyed, a force in the direction opposite to the document feeding direction from the separation feeding unit acts on the document, and the rotating body rotates in the reverse direction. And a control means for controlling the sheet processing means so as not to perform the predetermined processing on the sheet based on the accompanying reverse rotation distance.

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