JP7011464B2 - Document transfer device and image reader - Google Patents

Description

The present invention relates to a technique for detecting a transport state of a document in an image reading device including a document transport device capable of transporting a document and a document transport device.

A sensor (resist) for detecting that a document has reached the resist roller immediately after the resist roller in a document transfer device that sequentially separates and conveys a plurality of originals and an image reader that reads an image of the conveyed original. The configuration for arranging the rear sensor) is known. In Patent Document 1, the timing of detecting a document by a sensor is regarded as the timing when the document reaches the resist roller, and the timing of stopping the rotation of the separation roller and starting the reading operation of the image reading sensor is determined based on the timing. The techniques to control are described.

Japanese Unexamined Patent Publication No. 11-263464

In the document transporting device and the image reading device, it is required to detect the timing at which the document reaches the resist roller more accurately, thereby appropriately controlling the timing of feeding the document and reading the image. However, in the above-mentioned conventional technique, it is difficult to arrange the post-resist sensor for detecting the arrival of the original on the resist roller at the same position as the resist roller in the direction of transporting the original, and the sensor is arranged on the downstream side of the resist roller. Is common. In this case, there will be a time lag between the time the original reaches the resist roller and the time it is detected by the sensor after registration.

In particular, when the post-resist sensor is placed at one location in the center in the width direction of the sheet, if the document is conveyed in an oblique state, the preceding end of the document reaches the resist roller and then the sensor is concerned. The time difference until the center of the document is detected by the sensor after registration becomes larger. As a result, the time from when the tip of the document reaches the resist roller until the rotation of the separation roller is stopped becomes long, and the load on the document by the separation roller increases. Further, if the scanning start timing of the image is delayed or the scanning end timing is advanced, the image is scanned in a state where the image at the front end or the rear end of the document is chipped according to the amount of skew generated in the document. ..

The present invention has been made in view of the above problems. An object of the present invention is to provide a technique for more accurately detecting the timing at which the tip of a sheet (original document) to be conveyed reaches a roller (resist roller or the like) on a transfer path.

The document transporting apparatus according to one aspect of the present invention is fed by a document table on which a document is placed, a feeding means for feeding a document placed on the document table to a transport path, and the feeding means. It is detected by the transport means for transporting the original document in the transport path, the detection means for detecting the amount of movement of the document in the transport direction on the upstream side of the transport means in the transport direction of the document, and the detection means. The moving speed of the document is acquired based on the moving amount, and the timing at which the moving speed changes from the moving speed corresponding to the feeding by the feeding means to the moving speed corresponding to the feeding by the feeding means is determined. It is characterized by comprising a control means for detecting the timing at which the document reaches the transport means.

According to the present invention, it is possible to more accurately detect the timing at which the tip of the sheet (original document) to be conveyed reaches a roller (resist roller or the like) on the transfer path. As a result, even if the sheet is skewed, it becomes possible to more appropriately control the timing of the sheet feeding operation and the timing of the image reading operation.

The cross-sectional view schematically which shows the structure of the image reading apparatus which concerns on 1st Embodiment. The schematic diagram which shows the structure of the main part of the image reader of FIG. 1 schematically. A partial cross-sectional view schematically showing the arrangement of optical sensors. The schematic diagram which shows the structure of the optical sensor schematicly. The figure which shows the change example of the moving speed of a sheet by an optical sensor. A flowchart showing the procedure of the processing of the feeding system. The flowchart which shows the procedure of the processing of an image reading system. Sectional drawing which shows the example of the parameter for calculation of the sheet skew amount. FIG. 3 is a partial cross-sectional view schematically showing a configuration of an image reader according to a third embodiment. Sectional drawing which shows the example of the parameter for calculation of the sheet skew amount. FIG. 6 is a sectional view schematically showing another configuration example of an image reader. The schematic diagram which shows the structure of the main part of the image reader of FIG. 11 schematically.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It should be noted that the following embodiments do not limit the present invention according to the scope of claims, and not all combinations of features described in the present embodiment are essential for the means for solving the present invention. ..

[First Embodiment]
First, the document transfer device according to the first embodiment and the image reading device including the document transfer device will be described.

<Image reader 200>
FIG. 1 is a partial cross-sectional view schematically showing the configuration of an image reading device including a document transporting device according to the first embodiment, and FIG. 2 schematically shows a configuration of a main part of the image reading device of FIG. It is a schematic diagram which shows.

In FIGS. 1 and 2, the image reading device 200 includes a sheet capturing device 101. A plurality of sheets (manuscripts) are loaded (placed) on the sheet loading table (manuscript table) 1, and the sheet loading table 1 is configured to be able to move up and down. The loading platform drive motor 2 raises and lowers the seat loading platform 1. The seat detection sensor 3 detects that the seat loaded on the seat loading platform 1 is in the seat loading position. The seat loading detection sensor 12 detects that the seat is loaded on the seat loading surface 1a of the seat loading platform 1.

The pickup roller 4 (taking-in means) takes in the sheet (original document) of the sheet loading platform 1 and sends it out to the feeding roller 6. The pickup roller drive motor 5 rotates the pickup roller 4. In FIG. 2, the upper surface of the sheet is in the sheet taking-in position, and the taking-in of the sheet starts when the pickup roller 4 is rotated. Further, the pickup roller 4 can be moved to a seat taking-in position and a retracting position above the seat taking-in position by a driving means (not shown). The pickup roller 4 moves to the pick-up position when the seat is picked up, and to the retracted position when the seat is picked up.

The feeding roller 6 is provided on the downstream side of the pickup roller 4, and is driven by the feeding motor 8 to rotate in the direction of feeding the sheet to the downstream side in the transport direction. The separation roller 7 provided so as to face the feed roller 6 with the transport path interposed therebetween exerts a rotational force that rotates in the direction of pushing the seat back to the upstream side in the transport direction via a torque limiter (slip clutch) (not shown). I always receive it from. When there is one sheet between the feeding roller 6 and the separating roller 7, the feeding roller is more than the upper limit of the rotational force in the direction in which the separating roller 7 pushes the sheet back to the upstream side, which is transmitted by the torque limiter. Due to the frictional force between the sheet fed downstream by 6 and the separation roller 7, the rotational force in the direction in which the sheet is fed downstream exceeds the rotational force, and the separation roller 7 rotates following the feeding roller 6. (Take around).

On the other hand, when a plurality of sheets are present between the feeding roller 6 and the separation roller 7, the separation roller 7 receives rotation in the direction of pushing the sheet back to the upstream side from the roller shaft, and the other than the top sheet is downstream. Prevent it from being transported to the side.

Due to the action of feeding the sheet of the feeding roller 6 to the downstream side and the action of preventing the sheet of the separating roller 7 from being conveyed to the downstream side in this way, the sheets overlap with each other to form the feeding roller 6 and the separating roller 7. When fed to the nip portion of, only the top sheet is fed to the downstream side, and the other sheets are not transported to the downstream side, so that the overlapped sheets are separately fed. Therefore, the feeding roller 6 and the separating roller 7 form a pair of separating roller pairs 42. The separation roller pair 42 functions as an example of a sheet separation unit for separating and transporting a plurality of sheets to be transported one by one.
In this embodiment, the separation roller pair 42 is used, but instead of the separation roller pair 42, a separation belt roller pair in which either the separation roller or the feeding roller is used as a belt may be used. .. Further, the separation roller may be replaced with a separation pad to prevent the plurality of sheets from being conveyed to the downstream side by coming into contact with the sheets.

Further, by providing the double feed detection sensor 30 at a position where the separated sheets pass, it is possible to detect whether or not the sheets can be separated one by one by the sheet separating portion. In the present embodiment, a detection device using an ultrasonic transmission / reception unit is used as the double feed detection sensor 30, and double feed can be detected by the amount of ultrasonic wave attenuation between the transmission / reception units straddling the transport path.

The transfer motor 10 conveys the sheet after the sheet is separated to the image reading position where the image of the sheet (original) is read by the image reading sensors 14 and 15 (image reading unit), and further conveys the sheet to the ejection position. The resist roller 18 and the transfer rollers 21 and 23 are driven. By being driven by each roller, each roller on the opposite side (resist roller 17, transfer roller 20, 22) configured as a roller pair is driven, so that the sheet can be transported to the discharge position. Further, the transfer motor 10 drives each roller so that the transfer speed of the sheet can be changed according to the optimum speed for reading the sheet and the setting such as the resolution of the sheet. The resist clutch 19 drives the resist roller 18 or stops the drive by transmitting the rotational driving force of the transport motor 10 to the resist roller 18 (document transport unit) or blocking the transmission.

The nip adjustment motor 11 adjusts the pressure contact force that the feed roller 6 presses against the gap between the feed roller 6 and the separation roller 7 or the separation roller 7 via the sheet. As a result, the gap or pressure contact force suitable for the thickness of the sheet is adjusted, and the sheet can be separated.

The transfer roller pair composed of the transfer rollers 20 and 21, the transfer roller pair composed of the transfer rollers 22 and 23, and the roller pair on the further downstream side shown in FIG. 1 transfer the sheet to the discharge loading unit 44. The two guide plates, the upper guide plate 40 and the lower guide plate 41, guide the sheets conveyed by the separation roller pair, the resist roller pair, each transfer roller pair, and the downstream roller pair.

The image reading device 200 includes a control unit 45 that controls the operation of the entire device. The control unit 45 is composed of, for example, one or more processors (CPUs).

The image reading device 200 of the present embodiment includes an optical sensor 111 located at a position facing the seat loading platform 1 and at a position upstream of the pickup roller 4 in the seat transport direction. The optical sensor 111 is a sensor for detecting the behavior of the sheet to be fed (conveyed). In the present embodiment, the optical sensor 111 is used to detect the movement amount or the movement direction of the image pickup object (sheet). For example, the optical sensor 111 is used to detect the movement amount of the sheet in the transport direction and the movement amount in the direction orthogonal to the transport direction (the width direction of the sheet).

<Optical sensor 111>
FIG. 3 is a partial cross-sectional view schematically showing the arrangement of the optical sensor 111, and among the members shown in FIG. 1, the optical sensor 111, the seat loading platform 1, the pickup roller 4, the feeding roller 6, and the separation roller 7 are shown. Is extracted and shown. FIG. 3 shows the positional relationship of the optical sensor 111 with the seat loading platform 1. The optical sensor 111 is mounted on the substrate 100, and the substrate 100 is mounted at a position facing the seat loading platform 1 in parallel with the sheet loading platform 1. That is, the substrate 100 is attached so that the image pickup surface of the optical sensor 111 is parallel to the surface (opposing surface) of the sheet loading platform 1. The fact that the imaging surface of the optical sensor 111 is parallel to the surface of the sheet loading platform 1 is synonymous with the fact that the substrate 100 on which the optical sensor 111 is mounted is parallel to the surface of the sheet loading platform 1.

An area image sensor is used for the optical sensor 111. In the present embodiment, the optical sensor 111 is used as an image pickup element to acquire an image of the sheet to be conveyed, and the movement amount of the sheet is detected based on the image information to detect the behavior of the sheet. The optical sensor 111 uses an image sensor, which is an area image sensor, to image a conveyed sheet, acquire a two-dimensional image, and compare the images acquired in time series in the X and Y directions. The amount of movement of the two-dimensional sheet is detected. In the present embodiment, the optical sensor 111 is arranged so that the width direction of the sheet is the X direction and the transport direction of the sheet is the Y direction.

The optical sensor 111 is arranged so as to be separated from the image pickup reference plane in the transport path where the sheet is conveyed. The image pickup reference surface is a surface that faces the optical sensor 111, which is an image pickup element, and serves as a reference surface for image pickup by the optical sensor 111. The surface of 1) is defined as an imaging reference surface. However, in a situation where a plurality of sheets are loaded (placed) on the sheet loading platform 1, the position corresponding to the surface of the sheets to be transported becomes the imaging reference plane. That is, the surface of the seat loading platform 1 at the highest position in the elevating range of the sheet loading platform 1 when feeding the sheet substantially coincides with the imaging reference plane.

By separating the optical sensor 111 from the imaging reference plane by a predetermined distance, images of the sheet can be acquired at appropriate intervals regardless of the type of the sheet and the position where the optical sensor 111 is arranged. Therefore, it is preferable to use an optical sensor 111 whose imaging focus is on a sheet separated by a predetermined distance. In the present embodiment, the optical sensor 111 is arranged at a predetermined distance of about 20 mm to 30 mm and away from the image pickup reference surface.

In the present embodiment, the moving amount of the sheet is obtained by acquiring the image of the sheet at a predetermined time interval by the optical sensor 111 and comparing the images at the predetermined time interval (or the image based on the predetermined moving amount interval). To judge. The determination of the amount of movement of the sheet is performed, for example, by an IC provided on the substrate 100 on which the optical sensor 111 is mounted. In this case, the IC mounted on the substrate 100 functions as a movement amount detection unit. However, the image acquired by the optical sensor 111 may be transmitted to an external device to determine the movement amount on the external device, and in that case, it can be said that the movement amount detection unit includes the external device. In that case, the movement detection unit is configured to include the portion for determining the movement amount in the external device. The determination of the amount of movement of the sheet may be performed inside the optical sensor 111 as described later with reference to FIG. 4 (b).

As shown in FIG. 4A, when an optical member (lens 103 in this example) such as a prism or a lens (not shown) is arranged in front of the optical sensor 111 and is directly opposed to the opposite, the optical sensor 111 is used. The optical member is arranged so that the amount of light received by the lens is maximized. If there is no operational problem, these optical members can be omitted in order to prioritize miniaturization and cost.

To detect (determine) the movement amount or movement direction of the object to be imaged (sheet), an area image is acquired by the optical sensor 111, and the image obtained by A / D (analog / digital) conversion of the area image is sequentially obtained. It is done by comparing. In the present embodiment, a case where the optical sensor 111 is a sensor capable of detecting the moving amount or the moving direction of the image pickup object (the moving amount or the moving direction is detected inside the optical sensor 111) will be described. In this case, the optical sensor 111 includes a movement amount detection unit capable of detecting the movement amount or the movement direction of the image pickup object.

In the present embodiment, an image sensor (imaging element) is driven by a TG (Timing Generator) inside the optical sensor 111 to acquire an image signal, and A / D conversion and image signal analysis are performed to move an imaged object. A configuration for detecting the amount or the moving direction is adopted. Specifically, as shown in FIG. 4B, an image sensor, a TG, an AFE (Analog Front End), and a DSP (Digital Signal Processor) are provided inside the optical sensor 111 (so-called system on). -Composed of chips (SoC)). The optical sensor 111 acquires an area image (image signal) to be imaged by an image sensor driven by a TG, and performs A / D conversion on the acquired image signal by AFE. Further, the optical sensor 111 detects the amount of movement of the object to be imaged by the DSP based on the digital image signal after the A / D conversion. That is, the DSP functions as a movement amount detection unit.

As another example, the optical sensor 111 only acquires an image signal, and an image signal processing device (for example, an IC provided on the substrate 100 as described above) outside the optical sensor 111 performs A / D conversion. And the configuration for analyzing the image signal and detecting the moving amount or the moving direction of the image pickup object may be adopted.

In the present embodiment, in the acquisition of the image signal by the optical sensor 111, light is irradiated from the light source unit (light emitting element) to the image pickup object (sheet or the like), and the reflected light is received by the light receiving unit (image sensor) and photoelectric. It is done by converting. The light source unit included in the optical sensor 111 is composed of a laser or a light emitting diode (LED). That is, the optical sensor 111 irradiates the image pickup object with an infrared laser beam by a laser, or irradiates the image pickup object with light by using the light emitted by the LED, and receives the reflected light by the image pickup object. Acquires a surface image of an object to be imaged.

In particular, if a laser method is used for the light source unit, the amount of movement of the document can be detected in more detail, which is preferable. When the laser method is used, it is possible to reduce the decrease in the detection accuracy of the movement amount due to the fluttering of the document being conveyed by appropriately selecting the wavelength of the laser beam. For example, when the distance from the transport surface of the document to the optical sensor 111 is about 20 mm for the document transported in the transport path having a height of about 2 mm, infrared laser light having a wavelength of about 850 nm can be used. It has been experimentally clarified that the detection accuracy of the movement amount can be maintained even if the document being conveyed is fluttered.

In the present embodiment, as shown in FIG. 3, the pickup roller holding member 201 holding the pickup roller 4 extends to hold the optical sensor 111. The optical sensor 111 is covered with a case body 112. For the purpose of maximizing the detection area of the optical sensor 111, it is desirable that the optical sensor 111 is arranged so that the pickup roller 4 is not imaged and only the sheet is imaged (in a part of the image pickup area). However, if there is an area other than the sheet, the amount of movement or the amount of information for detecting the movement direction is small, which is a factor that lowers the detection accuracy).

<Detection of sheet transport status>
The image reading device 200 of the present embodiment detects the conveyed state of the sheet by using one optical sensor 111. Specifically, the image reading device 200 detects a sheet feeding abnormality that occurs during seat feeding, and detects a seat position that estimates the seat position. In the image reading device 200 of the present embodiment, the detection of the feeding abnormality of the sheet and the position detection of the sheet are executed by the control unit 45.

(Detection of abnormal sheet feeding)
The detection of the feeding abnormality of the sheet is realized by determining the occurrence of the feeding abnormality based on the movement amount of the sheet detected by the optical sensor 111 in both the transport direction and the width direction. .. Examples of sheet feeding abnormalities include jams in which the vicinity of the tip of the sheet is clogged in the feeding roller 6 or the transport path on the downstream side thereof, and when multiple sheets fastened with staples or the like are forcibly fed. It is included that the staple portion is damaged by separating the sheet. When the sheet feeding is normal, the movement amount in the width direction of the sheet is hardly detected (that is, the movement amount is almost 0), and the movement amount in the sheet transport direction is a value according to the feeding speed of the sheet. Stable and detected.

When a feeding abnormality occurs, for example, when the sheet is clogged and jam occurs, a sharp decrease in the amount of movement of the sheet in the transport direction is detected. Further, when a sheet fastened with staples is fed, the sheet rotates around the vicinity of the feeding roller 6, so that not only the amount of movement of the sheet in the transport direction but also the sheet is normally fed. It also detects the amount of movement of the sheet in the width direction, which is not detected in.

When the control unit 45 detects such a feeding abnormality (determines that a feeding abnormality has occurred), the control unit 45 immediately stops the seat feeding operation.

(Seat position detection)
The position detection of the sheet is realized by detecting the moving speed of the sheet in the transport direction and detecting the positions of the front end and the rear end of the sheet based on the change in the moving speed. Similar to the detection of the feeding abnormality, the movement amount of the sheet detected by the optical sensor 111 is used for detecting the movement speed of the sheet, but only the movement amount in the transport direction of the sheet is used (the width direction of the sheet). The amount of movement is not used). The control unit 45 obtains the movement amount (movement speed) per unit time based on the movement amount of the sheet in the transport direction detected by the optical sensor 111. Further, the control unit 45 detects the change in the moving speed by monitoring the change in the moving speed of the sheet, and the seat corresponding to the detection timing of the change in the moving speed and the peripheral speed of each roller on the transport path. The position of the seat is estimated based on the relationship with the moving speed of.

Next, the position detection of the sheet will be described in more detail with reference to FIG. FIG. 5 illustrates a change in the moving speed of a sheet obtained based on the amount of movement of the sheet in the transport direction detected by the optical sensor 111 when one sheet is fed from the sheet loading platform 1. .. In the present embodiment, the pickup roller 4, the feeding roller 6 (separation roller 7), and the resist rollers 17 and 18 are arranged in order from the upstream side in the sheet transport direction. The peripheral speed of these rollers used for feeding the sheet from the seat loading platform 1 to the transport path and transporting the sheet in the transport path is higher in the roller on the downstream side than in the roller on the upstream side in the transport direction of the sheet. It is desirable to be fast (the upstream roller is slower than the downstream roller). This is to prevent slack between the rollers in the sheets to be fed and conveyed, and to maintain an appropriate space between the sheets.

Specifically, the peripheral speed of the feeding roller 6 is faster than the peripheral speed of the pickup roller 4, and the peripheral speeds of the resist rollers 17 and 18 are faster than the peripheral speed of the feeding roller 6. The peripheral speed is controlled. For example, the peripheral speed of the pickup roller 4 is 400 [mm / sec], the peripheral speed of the feeding roller is 600 [mm / sec], and the peripheral speeds of the resist rollers 17 and 18 and the rollers on the downstream side thereof are 700 [mm / sec]. Is.

Each roller feeds or conveys the sheet by coming into contact with the sheet while rotating. The moving speed (transporting speed) of the sheet changes depending on the peripheral speed of the rollers contributing to the feeding or transportation of the sheet. Therefore, the control unit 45 can detect which roller the tip of the sheet has reached according to the change in the moving speed of the sheet.

In FIG. 5, by first starting the rotation of the pickup roller 4, the seat in the stopped state on the seat loading platform 1 starts to move. The maximum value of the moving speed of the seat at this time is equal to the peripheral speed of the pickup roller 4 (400 [mm / sec] in this example).

After that, when the tip of the sheet reaches the feeding roller 6, the feeding roller 6 starts feeding the sheet. As described above, the peripheral speed of the feeding roller 6 is faster than the peripheral speed of the pickup roller 4. Therefore, when the sheet reaches the feeding roller 6, the moving speed of the sheet rapidly increases. The control unit 45 detects such a change in the moving speed of the sheet (change from a speed slower than the moving speed within the feeding roller arrival detection range described later to a moving speed within the feeding roller arrival detection range). As a result, it is determined that the tip of the sheet has reached the feeding roller 6.

In the present embodiment, the condition (feeding roller arrival detection range) for determining that the tip of the sheet has reached the feeding roller 6 (between the feeding roller 6 and the resist rollers 17 and 18) is predetermined. For example, the condition is that the moving speed of the sheet is in a predetermined range including the peripheral speed of the feeding roller 6 (600 [mm / sec] in this example) (range of 450 to 650 [mm / sec] in this example). Is to be inside. The lower limit of this range (450 [mm / sec] in this example) is defined as a speed faster than the peripheral speed of the pickup roller 4. Further, even if the sheet reaches the feeding roller 6, the moving speed of the sheet is not necessarily equal to the peripheral speed of the feeding roller 6, and may be slower than the peripheral speed of the feeding roller 6. This is because the force returning to the upstream side by the separation roller 7 acts on the seat, which may cause slippage between the feeding roller 6 and the seat. Therefore, the range defined as the above conditions can be defined in a relatively wide range. In this example, the upper limit value in this range (650 [mm / sec] in this example) is set to a speed slightly faster than the peripheral speed of the feeding roller 6 as an example. In the present embodiment, the moving speed within the feeding roller arrival detection range shown in FIG. 5 is an example of the moving speed corresponding to the feeding by the feeding roller 6 (feeding means).

Next, when the tip of the sheet reaches the resist rollers 17 and 18, the moving speed of the sheet further increases. By detecting such a change in the moving speed of the sheet, the control unit 45 determines that the tip of the sheet has reached the resist rollers 17 and 18.

In the present embodiment, the condition (resist roller arrival detection range) for determining that the sheet tip has reached the resist rollers 17 and 18 is predetermined. For example, the condition is that the moving speed of the sheet is in a predetermined range (670 to 730 [mm / sec] in this example) including the peripheral speed of the resist rollers 17 and 18 (700 [mm / sec] in this example). ) Is inside. In the present embodiment, the resist roller arrival detection range is defined to be narrower than the feed roller arrival detection range. This is because after the tip of the sheet reaches the resist rollers 17 and 18, there is almost no slip between the roller and the sheet, and the moving speed of the sheet is stable.
In the present embodiment, the moving speed within the resist roller arrival detection range shown in FIG. 5 is an example of the moving speed corresponding to the transportation by the resist rollers 17 and 18 (transport means).

The control unit 45 detects the position of the tip of the sheet until the tip of the sheet reaches the resist rollers 17 and 18. After that, the control unit 45 shifts the process to the position detection of the rear end of the sheet.

After the tip of the sheet reaches the resist rollers 17 and 18, the moving speed of the sheet stabilizes at a speed equal to the peripheral speed of the resist rollers 17 and 18. On the other hand, when the rear end of the sheet passes through the position of the optical sensor 111 (that is, when it deviates from the imaging region by the optical sensor 111), the moving speed of the sheet detected based on the detection result of the movement amount by the optical sensor 111 is increased. It decreases sharply. The control unit 45 determines that the rear end of the sheet has passed the position of the optical sensor 111 in response to the detection of such a change in the moving speed of the sheet.

If the sheet to be conveyed next to the sheet being conveyed, which has passed the position of the optical sensor 111, is stationary on the sheet loading platform 1, the moving speed of the sheet is stopped by using the optical sensor 111. It is detected that the speed of the state changes to (0 [mm / sec]). However, there is a possibility that the sheet being transported is in contact with the next sheet and the next sheet may move in conjunction with the sheet being transported. In this case, the moving speed of the sheet detected by using the optical sensor 111 does not become zero. Therefore, a speed detection range for determining that the rear end of the sheet has passed the position of the optical sensor 111 may be set. In the present embodiment, as an example, the control unit 45 passes the position of the optical sensor 111 at the rear end of the sheet in response to the change in the moving speed of the sheet within the range of 300 [mm / sec] or less. Is determined. Although the details will be described later, for example, when the optical sensor 111 is provided downstream of the separation roller pair 42 as shown in FIGS. 11 and 12, when the sheet being transported passes through the position of the optical sensor 111. , The optical sensor 111 faces the surface forming the transport path, but in this case, of course, the amount of movement is not detected. That is, even in this state, the speed (0 [mm / sec]) in the stopped state is detected until the subsequent sheet to be conveyed reaches the position of the optical sensor 111.

By detecting the position of the sheet as described above, it is possible to detect that the tip of the sheet has reached the feeding rollers 6 or the resist rollers 17 and 18, and that the rear end of the sheet has passed the position of the optical sensor 111. It is possible.

<Feeding system processing>
Next, the procedure of the sheet feeding system processing in the image reading device 200 according to the present embodiment will be described with reference to the flowchart of FIG. The processing of each step in FIG. 6 is realized in the image reading device 200 by, for example, one or more CPUs included in the control unit 45 reading and executing a control program stored in a storage device (not shown). Will be done.

First, the control unit 45 waits until there is a sheet feeding command issued in the image reading system processing described later (“NO” in S101). When the feeding command for one sheet is issued (“YES” in S101), the control unit 45 starts feeding the sheet from the sheet loading platform 1 to the transport path.

Specifically, the control unit 45 enables the detection function of the feeding abnormality in order to start the detection of the feeding abnormality of the sheet based on the movement amount of the sheet detected by the optical sensor 111 as described above (the control unit 45 is effective. (ON) (S102). As a result, the control unit 45 controls the drive mechanism of each roller so that the feeding operation of the seat is immediately stopped when a feeding abnormality occurs during the feeding of the seat. The control unit 45 also enables (ON) the seat position detection function using the optical sensor 111 (S103). At that time, the control unit 45 first detects the arrival of the seat tip at the feeding roller 6, and in S103, the control unit 45 detects the arrival at the feeding roller 6 as a setting for detecting the position of the seat. Set the conditions.

Next, the control unit 45 starts feeding the seats from the seat loading platform 1. Specifically, the control unit 45 starts the rotation of the feeding roller 6 (S104) and starts the rotation of the separating roller 7 (S105), thereby enabling the sheet to be separated and fed. Further, the control unit 45 moves the pickup roller 4 to the intake position (S106), and rotates the pickup roller 4 in a state where the pickup roller 4 is in contact with the seat (S107). As a result, the seat on the seat loading platform 1 starts to move toward the feeding roller 6.

After that, the control unit 45 determines whether or not the tip of the sheet has reached the feeding roller 6 by the position detection function using the optical sensor 111 (S108). When the position detection function detects that the tip of the sheet has reached the feeding roller 6 (“YES” in S108), the control unit 45 sets the setting for detecting the position of the sheet to the next detection target, the resist roller. Switch to the condition setting for detecting the arrival of the tip of the sheet at 17 and 18 (S109). Further, since the seat reaches the feeding roller 6 and the pickup (pickup) operation becomes unnecessary, the control unit 45 stops the rotation operation of the pickup roller 4 (S110). Further, the control unit 45 moves the pickup roller 4 to the retracted position so that the seat does not touch the pickup roller 4 (S111). In addition, S110 and S111 may be performed at the same time, or may be performed in the reverse order.

After that, the control unit 45 determines whether or not the tip of the sheet has reached the resist rollers 17 and 18 by the position detection function using the optical sensor 111 (S112). When the position detection function detects that the tip of the sheet has reached the resist rollers 17 and 18 (“YES” in S112), the control unit 45 disables (OFF) the detection function of the sheet feeding abnormality (OFF). S113). This is because the feeding of the sheet is completed when the tip of the sheet reaches the resist rollers 17 and 18. Further, the control unit 45 switches the setting for detecting the position of the seat to the condition setting for detecting (passing) the rear end of the seat at the position of the optical sensor 111 (S114). Further, the control unit 45 stops the feeding roller 6 and the separation roller 7 in order to end the seat feeding operation (S115, S116).

Next, the control unit 45 determines whether or not the rear end of the sheet is detected at the position of the optical sensor 111 by the position detection function using the optical sensor 111 (S117). When the rear end of the seat is detected by the position detection function (“YES” in S117), the control unit 45 estimates the timing at which the rear end of the seat passes the position of the feeding roller 6 (S118). The time required for the rear end of the sheet to move from the position of the optical sensor 111 to the position of the feeding roller 6 is the distance from the position of the optical sensor 111 to the position of the feeding roller 6 in the transport path and the moving speed of the sheet. It can be estimated by multiplying by (carrying speed). By waiting for the estimated time, the control unit 45 can wait until the rear end of the seat passes the position of the feeding roller 6.

When the control unit 45 determines that the rear end of the sheet has passed the position of the feeding roller 6 (“YES” in S119), the control unit 45 completes the feeding operation of one sheet and returns the process to S101. As a result, the control unit 45 waits until the feeding command for the next sheet is issued by the image reading system processing described later.

<Image reading system processing>
Next, the procedure of the image reading system processing in the image reading device 200 according to the present embodiment will be described with reference to the flowchart of FIG. 7. The image reading system processing shown in FIG. 7 is executed in parallel with the feeding system processing shown in FIG. The processing of each step in FIG. 7 is realized in the image reading device 200 by, for example, one or more CPUs included in the control unit 45 reading and executing a control program stored in a storage device (not shown). Will be done. The sheet position detection in the image reading system processing is executed according to the setting in the feeding system processing of FIG.

First, the control unit 45 uses the seat loading detection sensor 12 to determine whether or not the seat is loaded on the seat loading platform 1 (S201), and if the seat is not loaded (“NO” in S201). , The image reading system processing is terminated. If the seats are loaded on the seat loading platform 1 (“YES” in S201), the control unit 45 issues a feeding order for feeding one seat by the feeding system processing (S202).

After that, the control unit 45 waits until the reading of the preceding paper by the image reading sensors 14 and 15 is completed (S203). When the reading of the preceding paper is completed, the control unit 45 proceeds to S204. When reading the first sheet of one or more sheets (original documents) loaded on the sheet loading table 1 (that is, when there is no preceding paper), the control unit 45 processes S204. Proceed to.

In the image reading system processing, it is necessary to appropriately determine the timing at which the image reading sensors 14 and 15 start reading the image of the conveyed sheet (original). Therefore, the control unit 45 determines the timing at which the image reading is started based on the timing at which the sheet (tip) transported along the transport path reaches the resist rollers 17 and 18.

Specifically, when the control unit 45 detects that the tip of the sheet has reached the resist rollers 17 and 18 by the position detection function of the sheet (“YES” in S204), the tip of the sheet is the image reading sensor 14. , 15 Estimates the timing to reach the reading position. The timing at which the tip of the sheet reaches the reading position can be determined based on the distance from the positions of the resist rollers 17 and 18 to the reading position by the image reading sensors 14 and 15 and the moving speed (conveying speed) of the sheet. The control unit 45 waits until the tip of the sheet reaches the reading position (S205), and determines that the tip of the sheet has reached the reading position (“YES” in S205), the sheet by the image reading sensors 14 and 15. The reading of the image of is started (S206).

Next, when the control unit 45 detects that the rear end of the conveyed sheet has passed the position of the optical sensor 111 by the sheet position detection function (“YES” in S207), the control unit 45 uses the detection timing as a reference as a reference. The timing at which the reading of the image is finished is determined (S208). Specifically, the control unit 45 has the image reading sensors 14 and 15 at the rear end of the sheet based on the distance from the position of the optical sensor 111 to the reading positions of the image reading sensors 14 and 15 and the transport speed of the sheet. Estimate the timing to reach. The control unit 45 determines the estimated timing as the timing at which the image reading sensors 14 and 15 finish reading the image. The control unit 45 finishes reading the image by the image reading sensors 14 and 15 at the determined timing.

When the rear end of the sheet being transported passes the position of the feeding roller 6, the feeding of the next sheet can be started. Therefore, the control unit 45 determines whether or not the rear end of the sheet being conveyed has passed the position of the feeding roller 6 by the position detection function of the sheet (S209). This determination is the same as the determination in S119. When the rear end of the sheet being conveyed passes the position of the feeding roller 6 (“YES” in S209), the control unit 45 returns the process to S201.

As described above, the image reading device 200 of the present embodiment includes a sheet loading platform 1 on which a document is placed, a feeding roller 6, resist rollers 17 and 18, an optical sensor 111, and a control unit 45. To prepare for. The feeding roller 6 feeds the sheet (manuscript) placed on the sheet loading platform 1 to the transport path. The resist rollers 17 and 18 convey the originals fed by the feeding rollers 6 in the transport path. The optical sensor 111 detects the amount of movement of the document in the transport direction on the upstream side of the resist rollers 17 and 18 in the document transport direction. The control unit 45 acquires the moving speed of the original based on the moving amount of the original detected by the optical sensor 111, and the moving speed is the moving speed corresponding to the feeding by the feeding roller 6, and the resist roller is used. The timing at which the moving speed changes to correspond to the transport by 17 and 18 is detected as the timing when the document reaches the resist rollers 17 and 18.

According to the present embodiment, the timing at which the tip of the sheet reaches the feeding roller or the resist roller by detecting the position of the sheet using the optical sensor 111 arranged on the upstream side of the pickup roller 4 in the sheet conveying direction is determined. It can be detected with high accuracy. Therefore, it is not necessary to provide a sensor (for example, a pre-resist sensor and a post-resist sensor) for detecting the arrival of the sheet on each roller in the transport path. Further, even when such a sensor is provided, since the sensor cannot be arranged at the same position as the roller, it is not always possible to accurately detect the arrival of the sheet on the roller. On the other hand, according to the present embodiment, it is possible to detect the arrival of the sheet on the roller more accurately than in the case where the sensor for detecting the sheet is provided near the roller.

Therefore, it becomes possible to more appropriately control the timing of various operations in the image reading device 200 based on the result of the seat position detection. For example, by accurately detecting the arrival of the tip of the sheet at the feeding roller 6, it is possible to finish the operation of taking the sheet into the transport path at an appropriate timing, and it is possible to realize a feeding in which jam is less likely to occur. .. Further, by being able to accurately detect the arrival of the tip of the sheet at the resist rollers 17 and 18, it is possible to end the sheet feeding operation at an appropriate timing, and it is possible to realize transportation in which jam is less likely to occur. Further, it becomes possible to start reading the image at an appropriate timing.

According to the present embodiment, even if the sheet to be conveyed is skewed, it is possible to detect the timing at which the tip of the sheet first reaches the resist roller by using one optical sensor 11. When a sensor used for a pre-resist sensor or the like is used, it only detects the arrival of the original, and if the sheet is skewed, a part of the sheet reaches the downstream side in the transport direction from the sensor. There may be. In the present embodiment, by using the optical sensor 111, it is possible to appropriately control the timing at which the image reading sensors 14 and 15 start reading the image of the sheet regardless of the skew of the sheet, and the skew of the sheet occurs. At times, it becomes possible to read an image without chipping the image at the tip of the sheet. Further, it is not necessary to arrange a plurality of sheet detection sensors in the width direction of the sheet in order to detect the skew of the sheet, and it is possible to prevent the image of the tip portion of the sheet from being chipped when reading the image.

In this embodiment, various changes can be made as follows. In the present embodiment, an optical sensor 111 capable of detecting the amount of movement of the seat in the X direction and the Y direction is used for detecting the position of the seat, but the present invention is not limited to this. For example, a roller that follows the movement of the sheet and an encoder that detects the amount of rotation of the roller may be provided. In this case, the encoder is used to detect the amount of rotation of the rollers as the amount of movement of the sheet.

Further, instead of providing the optical sensor 111 for detecting the position of the seat, when a one-way clutch is inserted in the shaft for transmitting the driving force to the feeding roller 6 to transmit the driving force in only one direction, the feeding force is supplied. The rotation amount of the feed roller 6 may be detected. While the sheet is being fed by the feeding roller 6, the rotation speed (peripheral speed) of the feeding roller 6 driven by the feeding motor 8 may be detected as the moving speed of the sheet. When the sheet reaches the resist rollers 17 and 18 which are faster than the feeding roller 6, the feeding roller 6 rotates in conjunction with the transfer of the sheet. Therefore, even if such a configuration is adopted, it is possible to detect that the tip of the sheet has reached the resist rollers 17 and 18.

In the present embodiment, the seat loaded on the seat loading platform 1 is taken into the transport path by the pickup roller 4 toward the feeding roller 6. However, as the configuration of the image reading device (document transporting device), it is also possible to adopt a configuration that does not use a pickup roller (capturing means). For example, in the image reading device 200 shown in FIGS. 1 and 2, if the sheet loading platform 1 is provided so as to be inclined with respect to the installation surface of the image reading device 400, the sheet loaded on the sheet loading platform 1 is provided. Reaches the separation roller pair 42 by its own weight. The sheets that have reached the separation roller pair 42 are separated one by one by the separation roller pair 42 and taken into the transport path. The configuration on the downstream side of the feed roller 6 in the sheet transport direction can be realized in the same manner as the configurations shown in FIGS. 1 and 2.

11 and 12 show another example of an image reading device (document transporting device) having a configuration that does not use a pickup roller (capturing means). The image reading device 400 basically has the same configuration as the image reading device 200 (FIGS. 1 and 2), but is located on the downstream side of the separation roller pair 42 in the transport direction, not on the upstream side. The optical sensor 111 is arranged, and the pickup roller is not provided.

In the image reading device 400, the seat loading surface 1a and the transport path of the sheet loading platform 1 are provided so as to be inclined with respect to the installation surface of the image reading device 400. As shown in FIGS. 11 and 12, the seat loaded on the seat loading platform 1 has a separation roller pair 42 (feeding roller 6 and separation roller 7) provided on the downstream side of the sheet loading platform 1 in the sheet transport direction. ) By its own weight. The sheets that have reached the separation roller pair 42 are separated one by one by the separation roller pair 42 and taken into the transport path.

Also in the image reader 400, each roller (resist roller, transfer roller, etc.) on the downstream side is set based on the detection result of the amount of movement of the sheet using the optical sensor 111 arranged on the downstream side of the separation roller pair 42. It is possible to accurately detect the timing at which the sheet arrives. Therefore, it is possible to obtain the same effect as the above-mentioned effect in the image reading device 200. It should be noted that not only the first embodiment but also the second and third embodiments described later can be applied to the image reading device 400.

In the image reading device 400, the feeding roller 6 is often provided mainly only in the central portion in the width direction of the transport path. On the other hand, the transfer rollers are often uniformly arranged with a certain gap in the width direction of the transfer path, that is, the detection of the timing at which the sheet reaches the transfer roller is the tilt of the sheet. It is easy to detect accurately regardless of the line.

[Second Embodiment]
Next, the document transfer device according to the second embodiment and the image reading device including the document transfer device will be described. The parts common to the first embodiment will be omitted, and the differences from the first embodiment will be mainly described.

In the present embodiment, the control unit 45 obtains the amount of skew of the sheet when the control unit 45 detects that the tip of the sheet has reached the resist rollers 17 and 18 in the position detection of the sheet. The control unit 45 determines the obtained skew amount together with the detection result of the rear end of the sheet using the optical sensor 111, the timing at which the image reading sensors 14 and 15 finish reading the image, and the feeding of the next sheet. Used to determine when to start. Further, the control unit 45 uses the obtained skew amount as one of the determination conditions for detecting the feeding abnormality of the sheet.

<Detection of skew amount of sheet>
FIG. 8 shows the timing at which the sheet position detection function using the optical sensor 111 detects that the tip of the sheet has reached the feeding roller 6 in the paper feeding system processing of FIG. 6 (“YES” in S108). , It is a figure which shows the example of the position of a sheet on a transport path. The nip portion between the feeding roller 6 and the separation roller 7 and the nip portion between the resist roller 17 and the resist roller 18 are shown as shaded areas.

In FIG. 8, when even a part of the tip of the skewed sheet reaches the nip portion between the feeding roller 6 and the separating roller 7, the moving speed of the sheet changes. As a result, the position detection function using the optical sensor 111 detects that the tip of the sheet has reached the feeding roller 6. Hereinafter, an example of a method of detecting the amount of skew of the sheet when the tip of the sheet reaches the resist rollers 17 and 18 will be described using the parameters x1, x2, x3 shown in FIG.

Here, the maximum width of the nip portion between the feeding roller 6 and the separation roller 7 is W1, the maximum width of the resist rollers 17 and 18 is W2, and the maximum width of the resist roller 17 and 18 is from the center of the feeding roller 6 in the sheet transport direction. Let L be the distance to the resist rollers 17 and 18. Further, the amount of skew in the center in the width direction of the sheet when the tip of the sheet reaches the resist rollers 17 and 18 is defined as (x2 + x3).

First, the moving distance x1 of the sheet from the state where the tip of the sheet reaches the feeding roller 6 (FIG. 8) until the arrival of the tip of the sheet at the resist rollers 17 and 18 is detected by the position detection function. Is obtained as an integrated value of the amount of movement detected by the optical sensor 111. Further, x2 is obtained as x2 = L−x1. Further, x3 can be obtained by x3 = x2 {W1 / (W2-W1)}. As a result, the amount of skew of the sheet (x2 + x3) is obtained.

The amount of skew of the sheet obtained as described above can be accurately calculated when the preceding angle of the sheet passes through the same position as the end portion of the resist rollers 17 and 18 in the width direction in FIG. However, if the width of the conveyed sheet is extremely wider or narrower than the width of the sheet shown in FIG. 8, the amount of skew of the sheet cannot be calculated accurately. By reducing the width W2 of the resist rollers 17 and 18 to about half the maximum width of the sheet that can be conveyed, it is possible to calculate the skew amount with a certain degree of accuracy regardless of the width of the sheet. Actually, the skew amount may be obtained by calculating the approximate value of the skew amount by the above method and correcting it with the margin of the predetermined amount.

<Control based on the amount of skew>
The control unit 45 uses the skewed amount of the sheet detected as described above for estimating the timing (S118) at which the rear end of the sheet passes the position of the feeding roller 6 in the paper feeding system processing (FIG. 6). .. In the first and second embodiments, the optical sensor 111 is arranged at the center in the width direction of the sheet. In this case, if the sheet is skewed, the detection result of the rear end of the sheet using the optical sensor 111 does not consider the end located at the most downstream side of the sheet in the transport direction. As a result, when the feeding of the next sheet is started, the sheet may collide with the skewed preceding sheet.

Therefore, in the present embodiment, in S118, the control unit 45 has the rear end of the sheet based on the distance obtained by adding the detected skew amount to the distance from the position of the optical sensor 111 to the position of the feeding roller 6. The timing of passing through the position of the feeding roller 6 is estimated. As a result, the control unit 45 delays the timing of determining that the rear end of the sheet passes through the position of the feeding roller 6 in the first embodiment by the detected skew amount. With such control, it is possible to prevent the sheet from colliding with the skewed preceding sheet when the feeding of the next sheet is started.

The control unit 45 further uses the detected skew amount for determining the timing (S208) for ending the image reading by the image reading sensors 14 and 15 in the image reading system processing (FIG. 7). In the process of FIG. 7, when the control unit 45 detects that the tip of the sheet has reached the resist rollers 17 and 18 (“YES” in S204), the control unit 45 detects the amount of skew of the sheet as described above. .. Here, the timing at which the image of the sheet is started to be read is appropriately controlled by using the optical sensor 111 regardless of the amount of skew of the sheet. On the other hand, the timing at which the reading of the image is finished is controlled based on the detection result of the rear end of the sheet using the optical sensor 111. Therefore, when the sheet is skewed, the amount of skew is taken into consideration. There is a need.

Therefore, in the present embodiment, the control unit 45 is S208 based on the distance from the position of the optical sensor 111 to the reading position of the image reading sensors 14 and 15 plus the detected skew amount. The timing at which the rear end reaches the image reading sensors 14 and 15 is estimated. As a result, the control unit 45 delays the timing of ending the image reading by the image reading sensors 14 and 15 in the first embodiment by the detected skew amount. According to such control, even if the sheet being conveyed is skewed, it is possible to read the image without chipping the image at the rear end portion of the sheet.

As described above, according to the present embodiment, by using the optical sensor 111 for detecting the position of the seat, it is possible to detect the skew amount of the seat without adding the seat detection sensor. In addition, the amount of skew of the detected sheet can be used to more appropriately control the feeding of the sheet and the reading of the image.

[Third Embodiment]
Next, the document transfer device according to the third embodiment and the image reading device including the document transfer device will be described. The parts common to the first and second embodiments will be omitted, and the differences from the first and second embodiments will be mainly described.

In the second embodiment, based on the amount of movement of the sheet detected by the optical sensor 111 from the timing when the tip of the sheet being conveyed reaches the feeding roller 6 to the timing when it reaches the resist rollers 17 and 18. The amount of skew of the sheet is detected. However, the moving speed of the sheet may not be stable until the tip of the sheet reaches the resist rollers 17 and 18. Therefore, in order to detect the amount of skew of the sheet more accurately, it may be necessary to detect the amount of skew of the sheet after the tip of the sheet reaches the resist rollers 17 and 18.

Therefore, in the image reading device 200 of the present embodiment, a post-resist sensor 33 is provided as a sheet detection sensor for detecting the presence or absence of the sheet on the downstream side of the resist rollers 17 and 18 in the sheet transport direction. FIG. 9 is a cross-sectional view showing a configuration example of the image reading device 300 according to the present embodiment. The image reading device 300 has a configuration in which a post-resist sensor 33 is added to the image reading device 200 of FIG. In the present embodiment, in the configuration shown in FIG. 9, after the tips of the sheets reach the resist rollers 17 and 18, the post-resist sensor 33 is used to determine the amount of skew of the sheet.

FIG. 10 is a diagram showing an example of the position of the sheet on the transport path when the tip of the sheet reaches the resist rollers 17 and 18. At this time, the distance from the resist rollers 17 and 18 to the resist post-resist sensor 33 in the center of the width direction orthogonal to the sheet transport direction is L, and the distance from the sheet tip to the resist rollers 17 and 18 is x. In this embodiment, x corresponds to the skew amount of the sheet.

In order to obtain the skew amount x of the sheet, the control unit 45 conveys the sheet by the resist rollers 17 and 18 from the state shown in FIG. 10, and determines the time until the tip of the sheet reaches the sensor 33 after resisting. measure. Further, the control unit 45 obtains the distance (L + x) that the sheet has moved based on the measured time and the moving speed (transporting speed) of the sheet. Further, the control unit 45 obtains the skew amount x by subtracting L from the distance (L + x).

In the second embodiment, when the sheet width is narrower than the width W2 of the resist rollers 17 and 18, the skew amount cannot be detected accurately. On the other hand, in the present embodiment, when the corner of the preceding sheet reaches within the range of the width W2 of the resist rollers 17 and 18, it is possible to accurately detect the amount of skew of the sheet.

The control unit 45 uses the sheet skew amount x detected in this way for controlling the timing of starting feeding of the sheet and controlling the timing of ending reading of the image, as in the second embodiment. It is possible.

As described above, according to the present embodiment, one sheet detection sensor (post-resist sensor 33) is added to the downstream side of the resist rollers 17 and 18 in the transport direction while using the optical sensor 111. , It becomes possible to improve the detection accuracy of the skew amount of the sheet.

[Other embodiments]
In the second and third embodiments described above, the amount of skew of the sheet detected by using the optical sensor 111 may be used for correcting the skew of the sheet. For example, in the image reading device 200 (or the image reading device 300, 400), the control unit 45 has a plurality of resist rollers 17 arranged along the width direction of the sheet based on the detection result of the skew amount of the sheet. By controlling the rotation speed of 18 (conveying roller), skew correction of the sheet may be performed.

Specifically, the control unit 45 rotates the left side resist rollers 17 and 18 and the right side resist rollers 17 and 18 as shown in FIGS. 8 and 10 based on the detected amount of skew of the sheet. The rotation speed of each roller is controlled (that is, it is controlled to a different rotation speed) so that there is a difference from the speed. As a result, when the sheet is conveyed by the resist rollers 17 and 18, the control unit 45 rotates the sheet in a direction in which the amount of skew is corrected (reduced) on a plane parallel to the surface of the transfer path. For example, in the state shown in FIGS. 8 and 10, by increasing the rotation speed of the resist rollers 17 and 18 on the right side from the rotation speed of the resist rollers 17 and 18 on the left side, the sheet rotates counterclockwise in the figure. , The amount of skew of the sheet is reduced.

Further, the control unit 45 may repeatedly execute the detection of the skew amount of the sheet and the skew correction. That is, after executing the above-mentioned skew correction, the control unit 45 detects the skew amount of the sheet again by using the optical sensor 111, and executes the skew correction again according to the detected skew amount. , The amount of skew of the sheet may be readjusted (re-corrected). This makes it possible to further enhance the effect of the skew correction based on the skew amount detected by using the optical sensor 111.

As described above, according to the present embodiment, the amount of skew of the sheet detected by using the optical sensor 111 can correct the skew of the sheet.

Although the document transporting device and the image reading device of the present invention have been described in detail above, the present invention is not limited to the above embodiment, and various improvements and changes can be made without departing from the gist of the present invention. ..

1: Seat loading platform, 1a: Seat loading surface, 2: Loading platform drive motor, 3: Seat detection sensor, 4: Pickup roller, 5: Pickup roller drive motor, 6: Feeding roller, 7: Separation roller, 8: Feeding motor, 9: Separation motor, 10: Conveyance motor, 11: Nip clearance adjustment motor, 12: Sheet loading detection sensor, 14, 15: Image reading sensor, 17, 18: Resist roller, 19: Resist clutch, 20 ~ 23: Conveyor roller 30: Double feed detection sensor, 33: Post-resist sensor, 40: Upper guide plate, 41: Lower guide plate, 42: Separation roller pair (sheet separation unit), 44: Discharge loading unit, 45: Control unit , 100: Substrate, 101: Sheet capture device, 102: Light source, 111: Optical sensor, 112: Case body

Claims (15)

The manuscript stand on which the manuscript is placed and
A feeding means for feeding the manuscript placed on the manuscript stand to the transport path, and
A transport means for transporting a document fed by the feed means in the transport path, and a transport means.
A detection means for detecting the amount of movement of the document in the transport direction on the upstream side of the transport means in the transport direction of the document.
The movement speed of the document is acquired based on the movement amount detected by the detection means, and the movement speed is changed from the movement speed corresponding to the feeding by the feeding means to the movement corresponding to the transportation by the transportation means. A control means for detecting the timing at which the speed changes as the timing at which the document reaches the transport means, and
A document transporting device characterized by being provided with. The document transfer device according to claim 1 and
A reading means for reading an image of a document conveyed by the document transfer device is provided.
The control means is an image reading device characterized in that it controls the timing at which the reading means starts reading the image of the document based on the detection result of the timing when the document reaches the transport means. The document transporting device according to claim 1, wherein the control means stops the feeding operation by the feeding means when the control means detects the timing at which the document reaches the transporting means. The detecting means detects the amount of movement of the document on the upstream side of the feeding means in the transport direction.
The control means is such that after the feeding means starts feeding the document, the moving speed of the document is slower than the moving speed corresponding to the feeding by the feeding means. The document transporting apparatus according to claim 1 or 3, wherein the timing at which the moving speed changes corresponding to the above is detected as the timing at which the document reaches the feeding means. Further provided with an importing means for fetching a manuscript placed on the manuscript stand and sending it to the feeding means.
The document transport device according to claim 4, wherein the control means stops the capture operation by the capture means when the control means detects the timing at which the document reaches the feeding means. After the control means detects the timing at which the document reaches the transport means, when the moving speed changes from the moving speed corresponding to the transport by the transport means to the speed in the stopped state, the moving document is being transported. The document transporting apparatus according to any one of claims 1 and 3 to 5, wherein a feeding operation by the feeding means is started for feeding the next document. The first aspect of the present invention is characterized in that, when the control means detects an abnormality in feeding the document based on the movement amount detected by the detection means, the control means stops the feeding of the document by the feeding means. And the document transporting apparatus according to any one of 3 to 6. The control means is characterized in that the feeding abnormality is detected based on the movement amount of the document in the transport direction and the movement amount in the width direction orthogonal to the transport direction detected by the detection means. The document transporting apparatus according to claim 7. The control means receives the movement amount detected by the detection means between the time when the feeding means starts feeding the document and the time when the document reaches the transporting means. It is also used for detecting the feeding abnormality, and is characterized in that it is used only for detecting that the rear end of the document passes through the feeding means after detecting the timing at which the document reaches the transporting means. The document transporting apparatus according to claim 7 or 8. The control means comes into contact with the movement amount of the document detected by the detection means from the timing when the document reaches the feeding means to the timing when the document reaches the transporting means, and the document in the feeding means. The amount of skew of the original document is based on the width of the possible region in the width direction orthogonal to the transport direction and the width of the region capable of contacting the document in the transport means in the width direction. The document transporting apparatus according to claim 4 or 5 , wherein the document transporting device is characterized by detecting the above. A document detecting means for detecting the passage of the document is further provided on the downstream side of the transport means in the transport direction.
The control means has the time from the timing when the document reaches the transport means to the timing when the document is detected by the document detecting means, and the transport in a region where the document can be in contact with the transport means. The document transporting apparatus according to claim 4 , wherein the skew amount of the document is detected based on the width in the width direction orthogonal to the direction. The document transporting apparatus according to claim 10, wherein the control means stops the transporting operation by the transporting means when the detected skew amount is a predetermined amount or more. The transport means has first and second transport rollers arranged side by side in the width direction.
The control means controls the rotation speed of the first transport roller and the rotation speed of the second transport roller to different speeds so that the detected skew amount is corrected. The document transporting apparatus according to any one of claims 10 to 12, wherein the skew correction is performed. The detection means has an image pickup element that receives light reflected by the document and performs photoelectric conversion, and is characterized in that the movement amount of the document is detected based on the image of the document acquired by the image pickup element. The document transfer device according to any one of claims 1 or 3 to 13. The document transporting apparatus according to any one of claims 10 to 12,
A reading means for reading an image of a document conveyed by the document transfer device is provided.
The control means ends reading an image by the reading means based on the timing at which the moving speed changes from the moving speed corresponding to the transportation by the transportation means to the speed in the stopped state and the skew amount. An image reader characterized by controlling the timing of operation.

Images