JP7195076B2 - document feeder - Google Patents

Description

The present invention relates to a technique for detecting an abnormality in the transport state of a document transport device capable of transporting documents.

Conventionally, an encoder that detects the amount of displacement of a document in the direction in which the document is transported is used to detect whether or not the document is being transported normally in a document transport device that transports a predetermined amount of paper. Then, a technique is proposed in which an optical sensor is used to measure the amount of displacement in a specific detection direction that is not orthogonal to the direction of conveyance, and the amount of skew is obtained from the amount of displacement in the direction of conveyance and the amount of displacement in the specific detection direction. (Patent Document 1).

JP 2013-209196 A

Here, when an optical sensor that measures the amount of displacement of a document in a specific direction is used, it may be affected by the amount of movement that is not related to transportation, that is, the variation in the position of the photoelectric conversion element itself. For example, there is a problem that the amount of displacement of the document cannot be detected due to movement other than the transport of the document, such as mechanical vibration transmitted to the photoelectric conversion element and vibration and movement of the document due to the rising of the document feeding table.

In view of the above, the document conveying device according to the present invention is
a manuscript placing table for placing a manuscript;
a transport unit for transporting the document along the transport path;
a movement amount detection unit that detects a movement amount of the document being conveyed by the conveying unit based on an image acquired by an imaging device that receives light reflected by the document and photoelectrically converts the light;
a paper feed unit that feeds the document from the document table;
a sheet feeding unit movement control section for repeatedly moving the sheet feeding unit between a sheet feeding state and a retracted state while the document is being conveyed by the conveying section;
The paper feed unit has a pickup roller for feeding the document from the document table,
The pickup roller continues to rotate until the document reaches the transport unit,
The movement amount detection section does not detect the movement amount when the sheet feeding unit movement control section moves the sheet feeding unit and immediately after that while the document is being conveyed by the conveying section. do.

According to the present invention, it is possible to reduce the influence of the vibration generated in the apparatus on the document displacement amount detected by the optical sensor, and to stably detect the document transport abnormality.

1 is a partial cross-sectional view schematically showing the configuration of a document conveying device according to a first embodiment of the present invention; FIG. 1 is a schematic diagram schematically showing the configuration of main parts of a document conveying device according to a first embodiment of the present invention; FIG. FIG. 2 is a partial cross-sectional view schematically showing the arrangement of optical sensors according to the first embodiment of the present invention; FIG. 2 is a schematic diagram schematically showing the configuration of an optical sensor; FIG. 4 is a schematic diagram schematically showing an image obtained by performing signal processing on an image obtained from an optical sensor; 4A and 4B are schematic diagrams showing the characteristics of the movement speed of an imaging target and the detection accuracy of an optical sensor; 4A and 4B are schematic diagrams showing an overlap before and after movement of an imaging target; FIG. FIG. 4 is a schematic diagram showing the characteristics of the detection accuracy of an optical sensor with respect to the degree of overlapping of imaging regions; FIG. 4 is a control flow diagram according to the first embodiment of the present invention; FIG. 2 is a top view showing an arrangement example of an optical sensor, a pickup roller, a separation roller, and an image reading sensor; FIG. 2 is a cross-sectional view showing an arrangement example of an optical sensor and a case body covering the periphery thereof; FIG. 4 is a cross-sectional view showing an arrangement example of an optical sensor in the middle of a sheet conveying path; The control flow figure concerning the 4th Embodiment of this invention. Another control flow diagram according to the fourth embodiment of the present invention. FIG. 11 is a partial cross-sectional view schematically showing the configuration of a document conveying device according to a fifth embodiment of the present invention; FIG. 11 is a schematic diagram schematically showing the configuration of main parts of a document conveying device according to a fifth embodiment of the present invention; FIG. 11 is a partial cross-sectional view schematically showing an opened state of an upper opening/closing unit of a document conveying device according to a fifth embodiment of the present invention; FIG. 11 is a top view schematically showing an upper opening/closing unit of a document conveying device according to a fifth embodiment of the present invention; FIG. 11 is a top view schematically showing an upper opening/closing unit of a document conveying device according to a sixth embodiment of the present invention; FIG. 11 is a diagram schematically showing a part of the configuration of a document conveying device according to a sixth embodiment of the present invention; FIG. 11 is a partial cross-sectional view schematically showing the configuration of a document conveying device according to a seventh embodiment of the present invention; FIG. 11 is a schematic diagram schematically showing the configuration of main parts of a document conveying device according to a seventh embodiment of the present invention; FIG. 11 is a schematic diagram showing the configuration of a paper feeding unit of a document conveying device according to a seventh embodiment of the present invention; FIG. 11 is a schematic diagram schematically showing another example of the configuration of the paper feeding unit of the document conveying device according to the seventh embodiment of the present invention; FIG. 11 is a partial cross-sectional view schematically showing the periphery of an optical sensor according to an eighth embodiment of the present invention;

[First Embodiment]
First, a document conveying device according to a first embodiment of the present invention will be described.

FIG. 1 is a partial cross-sectional view schematically showing the configuration of a document feeder (image reading device) according to the first embodiment of the present invention, and FIG. 2 is a configuration of the main part of the document feeder of FIG. It is a schematic diagram showing the.

1 and 2, the document conveying device 200 includes a sheet take-in device 101. As shown in FIG. A plurality of sheets are stacked on a sheet stacking table (original stacking table) 1, and the sheet stacking table 1 is configured to be vertically movable. The sheet stacking table driving motor 2 raises and lowers the sheet stacking table 1 according to an instruction from a sheet stacking table drive control section (original table movement control section) (not shown). A sheet detection sensor 3 detects that the sheets stacked on the sheet stacking table 1 are at the sheet take-in position. A sheet stacking detection sensor 12 detects that sheets are stacked on the sheet stacking surface 1 a of the sheet stacking table 1 .

The document feeding section 101 includes a pickup roller 4, a pickup motor 5, a pickup lifting motor 250, a pickup motor control section (not shown), a pickup roller lifting control section (not shown), a document table lifting control section (not shown), and the like. A pickup roller 4, which is an example of a document feeder, rotates in such a direction as to feed a sheet placed on the sheet stacking table 1 toward the downstream side in the conveying direction. The pickup roller 4 is rotationally controlled by a pickup motor 5 that receives an instruction from the pickup motor control section. In addition, the vertical movement of the pickup roller 4 is controlled by the pickup elevation motor 250 according to the instruction of the pickup roller elevation control section so that the pickup roller 4 contacts the uppermost sheet of the sheet stacking table. As a result, the document is sent from the sheet stacking table 1 to the document conveying section.

Since the document feeding unit 101 supports various paper types, a plurality of control methods can be selected. For example, in the case of normal paper, the pickup roller 4 is lowered by the pickup lifting motor 250 so that the pickup roller 4 is brought into contact with the sheet at the top of the sheet stacking table 1 before the start of conveyance, and the sheet is conveyed downstream from the sheet stacking table. (counterclockwise rotation in the drawing), and the rotation is continued until the sheet being conveyed reaches a document conveying unit, which will be described later. After the sheet reaches the document conveying unit, the rotation is stopped. A detection sensor may detect that the sheet has reached the document conveying unit. Subsequently, after detecting that there are no more sheets in the document conveying section, the pickup motor 5 starts rotating again.

In another example, in the case of paper that is thin and easily jammed, the pickup roller 4 is once lifted to a position where it does not come into contact with the sheet by the pickup lifting motor 250 at the start of conveyance. Subsequently, the pickup roller 4 is lowered by the pickup lifting motor 250, and after the completion of the lowering, the pickup roller 4 is rotated at a lower speed than in the case of conveying normal paper, and the sheet is sent to the document conveying section. After the sheet is delivered, the rotation of the pickup roller 4 is stopped, and the pickup roller 4 is lifted to a position out of contact with the sheet by the pickup lifting motor. In this manner, the document feeding unit feeds the document by means of the feeding control selected from a plurality of predetermined feeding controls.

A document feeding roller 6, which is an example of a document conveying unit, is driven by a feeding motor 8 so as to rotate in a direction in which the sheet is fed downstream in the conveying direction. The separation roller 7 constantly receives a rotational force for pushing back the sheet toward the upstream side in the conveying direction from the separation motor 9 via a torque limiter (slip clutch) (not shown). When one sheet is present between the feeding roller 6 and the separation roller 7, the separation roller 7, which is transmitted by the torque limiter, pushes back the sheet upstream from the upper limit value of the rotational force. The rotational force in the direction in which the sheet is fed downstream exceeds the rotational force in the direction in which the sheet is fed downstream due to the frictional force between the sheet fed downstream by and the separation roller 7, and the separation roller 7 rotates following the feeding roller 6 ( carry around).

On the other hand, when there are a plurality of sheets between the feed roller 6 and the separation roller 7, the rotational force of the separation roller 7 in the direction of pushing back the sheet toward the upstream side is applied to the sheet contacting the feed roller 6 and the other sheets. to exceed the frictional force between the uppermost sheet and the sheet other than the uppermost sheet to be conveyed to the downstream side.

In this manner, the action of the feeding roller 6 feeding the sheet to the downstream side and the action of the separation roller 7 preventing the sheet from being conveyed to the downstream side cause the sheets to overlap, causing the feeding roller 6 and the separation roller 7 to overlap each other. When fed to the nip portion, only the uppermost sheet is fed to the downstream side, and the other sheets are not fed to the downstream side, thereby separating and feeding the overlapping sheets. Therefore, the feed roller 6 and the separation roller 7 constitute a pair of separation rollers 42 (original separation portion). Although the separation roller pair 42 is used in this embodiment, a separation belt roller pair in which either the separation roller or the feeding roller is a belt may be used instead of the separation roller pair 42. . Further, the separation roller may be replaced with a separation pad, and the plurality of sheets may be prevented from being conveyed to the downstream side by coming into contact with the sheet.

Further, by providing the multi-feed detection sensor 30 at a position through which the separated documents pass, it is possible to detect whether the documents are separated one by one by the document separating section. In this embodiment, a detection device using an ultrasonic transmission/reception unit is used as the double-feeding detection sensor 30, and double-feeding can be detected by the amount of ultrasonic attenuation between the transmission/reception units across the conveying path.

The conveying motor 10 conveys the sheet after document separation to an image reading position where the image of the document is read by image reading sensors 14 and 15, and further conveys the sheet to a discharge position. drive control. Further, the conveying motor 10 drives each roller so that the sheet conveying speed can be changed according to settings such as the optimum speed for reading the sheet and the resolution of the sheet.

The nip gap adjustment motor 11 adjusts the gap between the feeding roller 6 and the separation roller 7 or the pressing force with which the feeding roller 6 presses against 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 registration clutch 19 transmits or interrupts the transmission of the rotational driving force of the transport motor 10 to the registration rollers 18 (original transport unit). By stopping the rotation of the pair of registration rollers including registration rollers 17 and 18, the leading edge of the sheet to be fed is brought into contact with the nip portion of the pair of registration rollers, thereby correcting the skew of the sheet.

A conveying roller pair composed of conveying rollers 20 and 21 , a conveying roller pair composed of conveying rollers 22 and 23 , and a downstream roller pair shown in FIG. Two guide plates, an upper guide plate 40 and a lower guide plate 41, guide the sheet conveyed by the pair of separation rollers, the pair of registration rollers, the pair of conveying rollers, and the pair of downstream rollers. The upper guide plate 40 forming the upper surface of the transport path is formed by part of an upper opening/closing unit 201, which will be described later. It is composed of a part of a housing (main unit) attached so as to be able to open and close by rotating.

The pre-registration sensor 32 is arranged upstream of the registration rollers including the registration rollers 17 and 18 and detects the conveyed sheet. The post-registration sensor 33 is arranged downstream of the registration roller pair formed by the registration rollers 17 and 18 and detects the conveyed sheet.

Here, the details of the main part of the embodiment of the present invention will be described with reference to FIGS. 3 and 4. FIG. A board 100 (imaging device board) mounted with an optical sensor 111 capable of detecting the behavior of a document transported to a position facing the sheet stacking table 1 is attached parallel to the sheet stacking table 1 . That is, the imaging surface of the optical sensor 111 is attached so as to be parallel to the surface (facing surface) of the sheet stacking table 1 . Here, an area image sensor is used as the optical sensor 111 . In the case of this embodiment, making the imaging surface of the optical sensor 111 parallel to the surface of the sheet stacking table 1 means that the substrate 100 on which the optical sensor 111 is mounted is parallel to the surface of the sheet stacking table 1. It is synonymous with becoming.

Here, in order to detect an abnormal transport state of the document more quickly and prevent the document from being damaged due to the transport error, it is desirable to arrange the optical sensor 111 as upstream as possible in the transport direction. In this embodiment, it is arranged upstream of the pickup roller 4 .

In this embodiment, the behavior of the document is detected by acquiring an image of the document being conveyed using the optical sensor 111 as an imaging device and detecting the amount of movement based on the image information. The optical sensor 111 is arranged at a predetermined distance from the imaging reference plane in the transport path along which the document is transported. The imaging reference plane is a plane facing the optical sensor 111, which is an imaging element, and serving as a reference for imaging by the optical sensor 111. In the present embodiment, the imaging reference plane is a transport path along which a document (sheet), which is an imaging target, is transported. The surface of (the sheet stacking table 1) is determined as the imaging reference plane. However, in a situation where a plurality of documents are placed on the sheet stacking table 1, the position corresponding to the surface of the document being conveyed becomes the imaging reference plane.

That is, the surface of the sheet stacking table 1 at the highest position in the vertical range of the sheet stacking table 1 when feeding the document approximately coincides with the imaging reference plane. By separating the optical sensor 111 from the imaging reference plane by a predetermined distance D, it is possible to acquire images of the document at appropriate intervals regardless of the type of the document or the position where the optical sensor 111 is arranged. Therefore, as the optical sensor 111, it is preferable to use a sensor that can focus on a document that is separated by a predetermined distance D. FIG. In this embodiment, the optical sensor 111 is separated from the imaging reference plane by a predetermined distance D of about 20 mm to 30 mm.

In this embodiment, the optical sensor 111 acquires an image of the document, and an IC provided on the substrate 100 on which the optical sensor 111 is mounted acquires an image at a predetermined time interval (or an image based on a predetermined movement amount interval). ) to determine the amount of movement, and the IC mounted on the substrate 100 operates as a movement amount detection unit. However, the image acquired by the optical sensor 111 may be transmitted to an external device, and the movement amount may be determined on the external device. In that case, the document conveying device in this embodiment is configured including the part that determines the amount of movement in the external device.

As shown in FIGS. 1 and 2, the sheet stacking table 1 is provided with movable regulating members 51 at both ends in the width direction with respect to the conveying direction to regulate the width of the sheet. By moving the regulating member 51 in the width direction to match the width of the document to be transported, it is possible to prevent the sheet from skewing during transport. In this embodiment, the optical sensor 111 may be attached to the regulation member 51 or may be attached to the exterior of the main body.

Also, as shown in FIG. 4A, when an optical member such as a prism or a lens (not shown) is arranged in front of the optical sensor 111 and the original is faced directly, the amount of light received by the optical sensor 111 is placed so that the maximum If there is no problem in operation, these optical members can be omitted in favor of miniaturization and cost.

In the embodiment of the present invention, a case where the optical sensor 111 is a sensor capable of detecting the movement amount of the document will be described.

In this case, the optical sensor 111 includes a movement amount detection unit (not shown) capable of detecting the movement amount or movement direction of the object to be imaged. An area image is acquired by the optical sensor 111 and converted into a digital signal by an A/D converter (not shown). Detects the amount or direction of movement of the sheet).

The optical sensor 111 in the present embodiment preferably obtains a surface image of a document by irradiating infrared laser light with a laser or using light emitted from an LED and receiving reflected light from the document or the like. In particular, the use of a laser system is preferable because it enables more detailed detection of the movement amount of the document. In the case of using the laser method, it is possible to reduce the deterioration in the movement amount detection accuracy due to the flapping of the document during transportation by appropriately selecting the wavelength of the laser light.

For example, when the distance D from the conveying surface of the document to the optical sensor 111 is approximately 20 mm for a document conveyed in a conveying path having a height of approximately 2 mm, an infrared laser beam having a wavelength of approximately 850 nm is used. It has been experimentally proven that the detection accuracy of the amount of movement can be maintained even if the document being conveyed flutters.

In this embodiment, the image sensor is driven by a TG (Timing Generator) inside the optical sensor 111 to obtain an image signal, A/D conversion and analysis of the image signal are performed, and the movement amount or movement direction of the object to be imaged is determined. It is configured to detect For example, as shown in FIG. 4B, the optical sensor 111 includes an image sensor, a TG, an AFE (Analog Front End), and a DSP (Digital Signal Processor). An image is acquired, A/D conversion is performed on the image signal acquired by the AFE, and the amount of movement of the object to be imaged is detected by DSP based on the digital image signal (so-called system-on-chip (SoC )It has become). That is, the DSP functions as a movement amount detection section.

As another case, the optical sensor 111 only acquires an image signal, and an image signal processing device (not shown) exists as a separate device, and this image signal processing device performs A/D conversion and analysis of the image signal. It may be configured to detect the amount of movement or the direction of movement of the object. In the present embodiment, the optical sensor 111 obtains an image signal by irradiating light onto a document, receiving the reflected light by a light receiving unit, and photoelectrically converting the light.

FIG. 5 shows a schematic diagram of an image obtained by performing signal processing on the image obtained from the optical sensor 111 . Points extracted as feature points from an image captured at a certain time (t=0) are represented by black squares. Here, as an example, 1 square = 1 pixel (that is, the number of pixels of the optical sensor 111 is 5 x 5 = 25 squares). may be formed. As an example, a point that is brighter or darker than other squares is extracted as a feature point. As feature points, unevenness and scratches on the surface of the document can be extracted.

When the time t′ has passed from this state, the optical sensor 111 acquires the image again, extracts the black masses, compares how the black masses (feature points) move, and determines the time Calculate the amount of movement from 0 to t'. In the example of FIG. 5, it is determined that the object has moved one square to the right and one square upward. Note that the calculation of the movement amount may be performed by the DSP inside the optical sensor 111 as described above, or may be performed in an image signal processing device provided separately from the optical sensor 111 .

Here, as described above, the imaging surface (light receiving surface) of the optical sensor 111 and the surface of the document are arranged so as to be parallel to each other. The characteristics of the optical sensor will be described with reference to FIG. 6. The optical sensor used in this embodiment is generally arranged such that the light receiving surface of the optical sensor and the document are parallel to each other, as shown in FIG. In the case of A (the left side of FIG. 6(b)), tracking is performed up to an area where the moving speed of the document to be imaged is faster than in the case of the arrangement B (the right side of FIG. 6(b)) in which the light receiving surface and the document are tilted. It is a characteristic that can be done.

Next, the details of the arrangement of the optical sensor 111 will be described using FIG. 3 again. Regarding the distance D between the optical sensor 111 and the sheet stacking table 1, L is the imaging range in the transport direction in the imaging area of the optical sensor 111, T is the image acquisition interval time of the sensor, and the maximum value of the transport speed of the document transport unit is is set to V, the distance D is adjusted so that the distance satisfies L≧T×V. Note that in the following description, L may also be expressed as an imaging area. The imaging area indicates the viewing angle of the optical sensor 111 on the imaging reference plane of the optical sensor 111. If there is an imaging target (document) on the imaging reference plane, an image within the imaging area can be obtained. can be done.

The conveying direction mentioned here does not mean the direction in which the document (sheet) is actually conveyed, but the direction in which the document (sheet) is to be conveyed by the device, that is, the direction along the rotation direction of the feeding roller and the conveying roller (the axis of each roller). vertical direction). Note that the image acquisition interval time of the sensor is T, but actually, a movement amount detection unit that detects the movement amount of the sheet based on the image acquired by the optical sensor 111 is provided, and the movement in the movement amount detection unit is The quantity acquisition interval should be T. In other words, the image acquisition interval time of the sensor is acquired at intervals shorter than T, and the movement amount is detected by the movement amount detection unit at intervals of T. In contrast, the input itself may not be performed. In the following explanation, the image acquisition interval time T of the sensor will be explained, but it has the same meaning as explained here, and can be read as the movement amount acquisition interval time T. FIG.

Here, when the angle of view (viewing angle) obtained by combining the optical sensor 111 and the optical members increases, the area that can be imaged at one time increases, so L has a large value. Also, since the optical sensor 111 has a certain viewing angle, L can also have a large value by increasing the distance D. FIG.

The image acquisition interval time T has a small value if the time required for the optical sensor 111 to acquire an image is short. Specifically, the faster the image readout clock of the optical sensor 111, the shorter the time required for the optical sensor 111 to read out the image signal. Alternatively, the smaller the number of pixels of the optical sensor 111, the shorter the time required to read the image signal. However, if the number of pixels is small, the value of L described above may also be affected (decreased).

Regarding the movement amount detection of the document as described above, if it is necessary to average a plurality of images obtained from the optical sensor 111 in order to detect the movement amount, it takes time until detection. In this case, it is necessary to replace the image acquisition interval time T with the movement amount detection interval time T′ and adjust the distance D between the optical sensor 111 and the sheet stacking table 1 so as to satisfy L≧T′×V.

However, since L≧T×V (or L≧T′×V) is the minimum condition, the present invention refers to a more optimal arrangement. For example, when the optical sensor of 5×5 pixels shown in FIG. 5 is used, the optical sensor captures an image once, but if the amount of displacement of the document is one pixel or less, extremely accurate detection is possible. It becomes possible. That is, it suffices to satisfy L≧T×V×5. From this relational expression, L/5T is obtained as the upper limit value Vmax of the document conveying speed for accurate detection.

Assuming that it is difficult to operate at this upper limit value Vmax, another form will be described with reference to FIGS. 7 and 8. FIG. FIG. 7 schematically shows the degree of overlapping (overlapping rate) of the imaging areas of the document at one time t1 and another time t2 (>t1). Among the regions captured by the optical sensor 111 at time t1 and time t2, the larger the overlapping region between the two images, the more feature points can be detected and tracked. can be detected more accurately. In this case, the optical sensor 111 is arranged so as to satisfy αL≧T×V, and the transport speed V is set using αL (α indicates the degree of overlapping of the imaging areas, α<1) in FIG. That is, from this relational expression, αL/T is obtained as the upper limit value Vmax of the document conveying speed.

As shown in FIG. 8, the detection accuracy of the optical sensor increases as the degree of overlapping of the imaging regions increases. If the detection algorithm is configured such that the detection accuracy is saturated at a predetermined degree of overlap α1 of the imaging regions, Vmax should be set so that the degree of overlap of the imaging regions is α1.

As an example, it is assumed that it is preferable that the overlapping area αL of the imaging pixels is N or more in order to increase the detection accuracy of the movement amount to a certain level. In this case, if the number of pixels in the transport direction of the optical sensor is L, the number of pixels in the transport direction may be overlapped by αL. In this case, L−V×T≧N (=αL). Therefore, in this case, by setting the transport speed so as to satisfy V≦(L−N)/T, the movement amount can be detected with high accuracy. As a specific example, when using the optical sensor shown in FIG. The conveying speed V may be set such that /T=1/T.

In this embodiment, as shown in FIG. 8, the detection accuracy rises to a point of saturation when the degree of overlap becomes α1=0.8. It is not necessary to succeed in detection continuously. The transport throughput can be improved by setting the transport speed to such an extent that the amount of movement can be detected, that is, the degree of overlap becomes α1 as the first threshold value. In this embodiment, when α=α1=0.6 (overlap rate 60%), good detection is possible and the load on the processing unit can be suppressed. Since αL=0.6×5=3.0, V≦2/T.

The above is just an example, and the characteristics of the detection accuracy differ depending on the optical sensor used. Although α=0.6 in the form, it may be changed.

Concerning the transport speed V, since it is the speed at which the document transport device transports the document, the speed increases stepwise (or steplessly depending on the type of motor) from the start of document transport until it reaches a predetermined speed. will do. Conversely, when the transport of the original is stopped, the speed also decreases stepwise (or steplessly) from the predetermined speed toward the stopped state (V=0).

As the set value of the above-described transport speed V, the speed V1 at the time when the transport speed reaches a predetermined speed after the start of document transport satisfies the above relational expression. is slower than V1, the detection accuracy of the optical sensor does not deteriorate, and the movement amount can be preferably detected.

Here, for example, if the apparatus does not have enough space, it is conceivable to arrange an optical member with a large angle of view in front of the optical sensor 111 to enlarge the imaging area L with respect to the transport direction. With this configuration, a higher transport speed V can be handled.

Alternatively, the image acquisition interval time T of the optical sensor 111 may be changed in conjunction with the change in the transport speed V. FIG. A target imaging overlap region (αL) is determined, and the above-mentioned TG controls the image acquisition interval time T so that the imaging overlap region is always constant even if the transport speed V changes. By performing this control, even if the conveying speed V changes, the detection accuracy of the optical sensor is always constant.

Similarly, in the present embodiment, instead of setting the transport speed V as described above, the image acquisition interval time T may be adjusted so that the overlapping degree α of the imaging regions is adjusted to a predetermined value. good. The detection accuracy of the optical sensor can be efficiently improved by setting the degree of overlap α to be α1. However, the present invention is not limited to this. good.

The output of the optical sensor may be output to an IC or the like that processes the output at a predetermined image acquisition interval time T, but another example will be shown below.

For example, when an optical sensor that outputs the amount of movement when the amount of movement detected by the optical sensor exceeds a predetermined value is used, a case of conveying 150 sheets/minute for conveying an A4 document will be described. The transport speed V is about 1000 mm/sec even if the distance between the documents is taken into account. In this case, as an example of the image acquisition interval time T, if the resolution of the optical sensor is set to 1500 cpi, that is, to output 1500 counts per inch, the movement is 1/1500 inch per count, that is, about 0.017 mm. If there is, it outputs one count. For a conveying speed V=1000 mm/sec, 1000/0.017≈60000 counts per second, that is, 1 count is output for 1/60000 sec.

As an optical sensor, as shown in FIG. 6A, when the conveying speed exceeds a predetermined value, the performance of the set resolution cannot be exhibited (detection accuracy decreases). On the other hand, by setting the resolution to about 1500 cpi so as to exhibit the same detection accuracy as the transport speed that can be set for the document transport device, the actually used transport speed V=1000 mm/sec. Under such conditions, the detection accuracy can be kept constant without lowering the resolution. In particular, as described with reference to FIG. 6B, by arranging the surface of the document and the imaging surface of the optical sensor so that they are parallel (left side of FIG. 6B), the performance of the set resolution is exhibited. That is, even if the conveying speed is increased, the set resolution performance can be maintained, and the detection accuracy of the optical sensor can be maintained.

In addition, some optical sensors have a resolution of 5000 cpi or more. If the resolution is increased, the detection accuracy of the optical sensor will be improved, but the spectroscopic sensor must be operated at high speed. Since the clock frequency is increased, the load and power consumption on ICs and the like that process the output of the optical sensor are also increased. Considering the detection of the transport state of the document as shown here, by setting the resolution to about 1500 cpi, sufficient detection accuracy can be achieved for the transport speed V of about 100 sheets/minute, which is required as the transport speed. can be secured, and the load on the processing can be suppressed.

Here, the paper feed unit will be described. The paper feed unit includes a pickup roller 4, a pickup motor 5, a pickup elevation motor 250, a pickup roller elevation control section (not shown), a pickup motor control section (not shown), and a document table elevation control section (not shown), all or part of which is a unit. It is a paper feed unit configured as

A pickup roller 4 (capturing means), which is an example of a document pickup section, feeds a sheet on the sheet stacking table 1 from the sheet stacking table 1 . A pickup roller driving motor 5 rotates the pickup roller 4 according to an instruction from the pickup motor control section. In FIGS. 1 and 2, the upper surface of the sheet is at the sheet take-in position, and when the pickup roller 4 is rotated, the take-in of the sheet is started. The state of the pickup roller 4 at this time is called a paper feed state.

Further, the pickup roller 4 can be moved between a sheet take-in position and a retracted position above the sheet take-in position by a pick-up roller elevating motor 250 according to an instruction from the pickup roller elevating control section. The pickup roller 4 moves to the take-up position when picking up the sheet, and moves to the retracted position when the pick-up is finished, according to the instruction of the pick-up roller elevation control. A state of the pickup roller 4 at the retracted position is called a retracted state.

In this manner, the pickup roller 4 repeats up and down motions during transport under the control of sheet feeding. At this time, the upward and downward movement of the pickup roller 4 vibrates the document itself, and vibrates the apparatus. When the document itself is vibrated, the amount of displacement of the document read by the optical sensor 111 may be added to the amount of displacement in a direction other than the direction in which the document is transported. Further, when vibration is applied to the apparatus, the vibration applied to the optical sensor 111 adds the amount of displacement corresponding to the vibration of the optical sensor 111 to the amount of displacement of the document in the conveying direction, and this also correctly determines the conveying state of the document. Can not do it.

Next, reading control of the optical sensor 111 will be described with reference to FIG. The paper feed sequence is as described above, and the pickup roller 4 moves to the take-up position when picking up the sheet, and moves to the retreat position when the pick-up is completed. In other words, the pickup roller 4 moves up and down while the document is being transported. There is a possibility that the optical sensor 111 may be subjected to a displacement due to the vibration due to the vertical movement of the pickup roller 4 other than the original displacement of the document.

Therefore, the reading timing is controlled as shown in FIG. That is, when the pickup roller 4 descends, the reading operation of the optical sensor 111 is temporarily stopped (S101). Next, after the reading sensor stops reading, the pickup roller 4 is lowered (S102), a waiting time of T1 time is inserted after the completion of the lowering (S103), and reading of the optical sensor is resumed after the waiting time has passed (S104).

The lifting process of the pickup roller 4 is the same, and the reading operation of the optical sensor 111 is temporarily stopped (S111). Next, after the reading sensor stops reading, the pickup roller is lifted (S112), a waiting time of T2 is inserted after the lifting is completed (S113), and reading of the optical sensor is resumed after the waiting time has passed (S114).

In this way, the reading of the optical sensor 111 is stopped while the pickup roller 4 is moving up and down, and there is a possibility that vibration due to the up and down movement of the pickup roller 4 is applied to the device before reading is restarted. , the reading operation is restarted after waiting time T1 or T2 at which the vibration is attenuated to such an extent that it does not affect the reading operation.

According to the configuration of the present embodiment, since a single optical sensor can detect the transport state of a document without being affected by vibration caused by vertical movement of the paper feed unit, the size and cost of the apparatus are not increased. It is possible to provide an apparatus capable of detecting the amount of displacement of a document with high precision using an optical sensor.

Further, in this embodiment, a light source unit 102 is provided for the purpose of increasing the amount of light received by the optical sensor 111 as shown in FIG. 4A. In this embodiment, the light source unit 102 is provided as a device separate from the optical sensor 111, but the optical sensor 111 and the light source unit 102 may be configured as one device.

In the present embodiment, the stop/restart of reading by the optical sensor is controlled in accordance with the vertical movement of the pickup roller 4. However, detection of the amount of movement is stopped by the movement amount detection unit while reading by the optical sensor 111 is continued. Alternatively, a configuration may be adopted in which only the determination of the movement amount is not performed while the movement amount detection unit is in operation. In other words, it is sufficient that the movement amount of the document is not determined during the period in which the vertical movement of the pickup roller affects the movement of the document. Stopping the reading of the optical sensor 111 also leads to a reduction in power consumption.

Further, in the present embodiment, the waiting times T1 and T2 from the completion of the vertical movement of the pickup roller 4 in the optical sensor 111 to the resumption of reading by the optical sensor 111 are set until the influence of the vibration caused by the vertical movement of the pickup roller 4 disappears. However, if the optical sensor 111 is not affected by vibration, T1 and T2 may be 0 seconds. Further, T1 and T2 may be switched inside the apparatus according to the operation state of the apparatus represented by the transport mode in document transport control, or may be set by an external control device.

Here, in the lifting or lowering control of the pickup roller 4 shown in FIG. You may stop conveying the document. According to this configuration, it is possible to shorten the time during which the document is transported while the reading by the optical sensor 111 is stopped, and it is possible to detect a transport abnormality based on the amount of movement of the document for a longer period of time.

Further, in the control flow shown in FIG. 9, instead of stopping the movement amount detection by the optical sensor 111, the conveyance abnormality determination condition based on the movement amount detection may be changed. For example, control may be performed to increase the number of pieces of movement amount detection data necessary to detect the occurrence of a transport abnormality from S101 to S104 in FIG.

In the above-described embodiment, the reading of the optical sensor 111 is stopped while the pickup roller 4 is moving up and down. Just before that, the pickup roller 4 may be controlled so as not to move up and down.

[Second embodiment]
Next, a document conveying device according to a second embodiment will be described. Since the basic configuration is the same as that of the first embodiment, only different parts will be described.

The details of the arrangement method of the optical sensor 111 will be described with reference to FIGS. 10 and 11. FIG. FIG. 10 is a diagram extracting the optical sensor 111, the pickup roller 4, and the feeding roller 6 when the document conveying device is viewed facing the sheet feeding surface. In this embodiment, as shown in FIG. 11, the member holding the pickup roller 4 extends and holds the optical sensor 111 . FIG. 11 is a cross-sectional view taken along line AA of the structure of FIG. 10, showing an example in which the optical sensor 111 is covered with a case body 112. As shown in FIG. In order to maximize the detection area of the optical sensor 111, it is desirable that the optical sensor 111 is arranged in a direction in which the pickup roller 4 does not pick up an image so that only the document is picked up (a part of the image pickup area is However, if there is an area other than the document, the amount of information for detecting the amount of movement or the direction of movement is reduced, which is a factor in lowering the detection accuracy).

11, in which the optical sensor 111 is arranged so that the wall surface of the case body 112 covering the periphery of the optical sensor 111, which is closer to the paper feeding surface, is arranged on the upstream side. When the optical sensor 111 is arranged in the direction in which the wall surface of the case body 112 with the shortest distance from the paper feeding surface is arranged on the downstream side, the optical sensor 111 can If it is possible to configure the detection area so that only the document is included, considering the generation of paper dust in the pickup roller 4 and the separation roller 7, the wall surface with the shortest distance from the paper feed surface is arranged on the downstream side. It is preferable to arrange the optical sensor 111 in an orientation. With this arrangement, it is possible to reduce the adhesion of paper dust to the surface facing the optical sensor 111 (translucent plate 112c in FIG. 12, which will be described later).

When a bundle of documents placed on the sheet stacking table 1 is continuously transported to a document feed port provided upstream of the transport path, the optical sensor 111 is provided at a position where a plurality of documents can pass simultaneously. It is possible to detect the trailing edge by imaging the trailing edge of the document. In the present embodiment, detection of the trailing edge of a document can utilize the variation in output caused by the trailing edge of a preceding document forming a shadow on the next document.

As a specific arrangement of the optical sensor 111, it is slightly upstream of the leading edge of the sheet stacking table 1 where the sheets are stacked. That is, it is a position facing the sheet stacking table 1 on the front end side of the sheet stacking table 1 . Further, by arranging the optical sensor 111 lower than the height of the paper feeding unit having the pickup roller 4 and the feeding roller 6, it is possible to suppress an increase in the size of the apparatus main body.

According to the configuration of this embodiment, it is possible to detect the transport state of the document with one optical sensor, and to detect the transport state after the document is regulated. Therefore, it is possible to detect the conveying state of the document without executing additional processing, so the processing time is not increased.

Therefore, it is possible to provide an apparatus that does not increase the processing time unnecessarily, without increasing the size and cost of the apparatus.

[Third Embodiment]
Next, a document conveying device according to the third embodiment will be described. FIG. 12 is a partial cross-sectional view schematically showing the configuration of the document conveying device according to this embodiment.

FIG. 12 is a cross-sectional view showing a configuration example of an optical sensor 111 whose periphery is covered with a mold member and a transparent plate. In the example of FIG. 12, the optical sensor 111 is mounted on the substrate 100. For example, a light-emitting element (laser light source) that outputs infrared laser light and a light-receiving element that receives the reflected light of the light output by the light-emitting element. and a sensor element including The light-emitting element and the light-receiving element are arranged at adjacent positions on the optical sensor 111 . Mold members 112 a and 112 b and a transparent plate 112 c shown in FIG. 12 form part of a case body 112 covering the optical sensor 111 . Mold members 112 a , 112 b form walls perpendicular to substrate 100 . The light-transmitting plate 112c is connected to the ends of the mold members 112a and 112b opposite to the ends on the substrate 100 side. In the arrangement of FIG. 12, the wall formed by the mold member 112b is longer than the wall formed by the mold member 112a so that the transparent plate 112c is inclined with respect to the surface of the substrate 100 or the imaging reference plane described above. ing.

The light-transmitting plate 112c transmits light emitted from the light-emitting element of the optical sensor 111 and directed toward the document. The light transmitted through the transparent plate 112 c and reflected by the original is transmitted through the transparent plate 112 c and received by the light receiving element of the optical sensor 111 . Such a configuration of the optical sensor 111 can prevent paper dust from directly adhering to the optical sensor 111 and can prevent paper dust from being erroneously extracted as a feature point. The wavelength of the light emitted by the optical sensor 111 (light-emitting element) is preferably in the near-infrared region of about 850 nm, and the light-transmitting plate 112c may be a filter capable of transmitting light in that band. preferable.

As shown in FIG. 12, the optical sensor 111 is arranged at a position between the transport rollers 1601 and 1602 in the middle of the transport path 1600 . Here, the conveying roller 1601 may be the feeding roller 6 or the separating roller 7 . In these cases, FIG. 12 is a schematic diagram showing the positional relationship, and it is assumed that the optical sensor 111 is actually smaller than the conveying roller 1601 .

In FIG. 12A, of the walls (mold members) 112a and 112b forming the case body 112, the long wall 112b is arranged on the upstream side in the sheet conveying direction, and the short wall 112a is arranged on the upstream side in the sheet conveying direction. placed downstream. This arrangement is effective in suppressing the influence of external light directed from the outside to the inside of case body 112 . As shown in FIG. 12B, the short wall 112a may be arranged on the upstream side in the sheet conveying direction, and the long wall 112b may be arranged on the downstream side in the sheet conveying direction. This arrangement suppresses the influence of paper dust when, for example, paper dust is likely to fly away from the conveying roller 1602 when the rotation speed of the conveying roller 1602 arranged on the downstream side is faster than that of the conveying roller 1601. effective for

[Fourth Embodiment]
Next, reading timing control of the optical sensor 111 regarding vertical movement of the platen will be described using a fourth embodiment. Note that the basic configuration of the document conveying device 200 is the same as that of the first embodiment.

In FIGS. 1 and 2, the sheet stacking table 1 is configured to be vertically movable. At the timing when the document starts to be transported, the sheet stacking table continues to operate according to instructions from the sheet stacking table elevation control unit (not shown) until the sheet detection sensor 3 detects that the document stacked on the sheet stacking table 1 is at the sheet loading position. A sheet stacking table 1 is lifted by a motor 2 . The state of the sheet stacking table 1 at this time is called a sheet feeding state. On the other hand, a state in which the sheet stacking table 1 is lowered so that the sheets stacked on the sheet stacking table 1 are positioned below the sheet take-in position is called a retracted state.

While the sheet stacking table 1 is at the sheet take-in position, the pick-up roller 4 feeds the document to the conveying section. When the document is sent to the conveying section, the document stacked on the sheet stacking table 1 is lowered from the sheet reading position by the thickness of the delivered document. Therefore, it is necessary to lift the document conveyed by the sheet stacking table driving motor 2 by the thickness thereof in order to send out the next sheet. For this reason, the sheet stacking table motor 2 is position-controlled by a sheet stacking table elevation control unit (not shown) so that the sheet detection sensor 3 is always at the sheet take-in position for the originals stacked on the sheet stacking table 1 .

The optical sensor 111 is located on the upstream side of the pickup roller 4 and detects the amount of movement of the uppermost document placed on the sheet stacking table 1 . Therefore, when the position control of the sheet stacking table 1 is performed, the sheet stacking table 1 moves up and down substantially perpendicular to the reading surface of the optical sensor 111, but does not move up and down completely vertically, but moves up and down while vibrating slightly. do. At this time, when the optical sensor 111 detects the amount of movement of the document, it also detects the amount of slight vibration due to vertical movement of the sheet stacking table 1 other than the original amount of movement of the document in the conveying direction. It becomes impossible to detect the amount of movement.

Therefore, as described with reference to the control flow of FIG. 13, when the sheet (original) stacking table 1 is to be raised, the reading operation of the optical sensor 111 is stopped (S121), and the sheet (original) stacking table 1 is moved to the sheet position. After raising the sheet (original) stacking table 1 to the take-in position (S122) and inserting a waiting time T3 (S123) so that the vibration of the sheet stacking table 1 itself due to the rise of the sheet (original) stacking table 1 does not affect the reading result of the optical sensor, Reading of the optical sensor is resumed (S124). As a result, it is possible to prevent misjudgment of the displacement applied to the document placed on the sheet stacking table 1 due to the rise of the sheet stacking table 1, which is not caused by the transport, as the movement amount due to the transport of the document.

Further, in the present embodiment, the stop/restart of reading by the optical sensor 111 is controlled in accordance with the upward movement of the sheet stacking table 1. It may be stopped, or a configuration may be adopted in which only the determination of the movement amount is not performed while the movement amount detection unit is in operation. In other words, it is sufficient if the movement amount of the document is not determined during the time period when the movement of the sheet stacking table 1 is affected. Stopping the reading of the optical sensor 111 leads to a reduction in power consumption.

Further, in the present embodiment, the waiting time T3 from the completion of the lifting operation of the sheet stacking table 1 of the optical sensor 111 to the restart of reading by the optical sensor 111 is the time until the effect of the vibration due to the lifting operation of the sheet stacking table 1 disappears. However, if the optical sensor 111 is not affected by vibration, T3 may be 0 seconds. Further, T3 may be switched inside the apparatus according to the operation state of the apparatus such as the transport mode, or may be configured so that the value can be set from an external control device. Further, the present embodiment may be implemented together with the control of the reading timing of the optical sensor 111 by the vertical movement of the pickup roller 4 described in the first embodiment.

In this embodiment, the reading operation of the optical sensor 111 is stopped during and immediately after the sheet stacking table 1 is raised. Conversely, control may be performed so that the sheet stacking table 1 is not moved up and down during and immediately before the reading operation of the optical sensor 111 . The sequence in that case will be described with reference to FIG. The sheet detection sensor 3 determines whether the sheet placed on the sheet stacking table 1 is at the sheet loading position (S131). S132). When the optical sensor is reading, a waiting time of T4 is provided (S134). When T4 has elapsed, it is determined again in S132 whether the optical sensor 111 is reading. If the optical sensor 111 is not reading, the sheet (original) stacking table 1 is raised (S133). With this configuration, it is possible to prevent misjudgment of displacement of the document placed on the sheet stacking table 1 due to the lifting of the sheet stacking table 1, which is not caused by conveyance, as the amount of movement caused by the conveyance of the document.

In this embodiment, it is preferable that the optical sensor 111 is configured to detect the trailing edge of the sheet. That is, when the optical sensor 111 is arranged on the upstream side of the pickup roller 4, the sheet conveyed by the pickup roller 4 is out of the imaging area of the optical sensor 111 at the timing when the trailing edge of the sheet is detected. becomes. Therefore, the reading by the optical sensor 111 can be stopped at this point, and if the reading is stopped here, the determination in S132 will be No, and the document table 1 can be raised in S133.

When the optical sensor 111 detects the trailing edge of the sheet, the pickup roller 4 is picking up the sheet. A change in pressure may cause a jam or break the sheet. Therefore, when the trailing edge of the sheet is detected and it is determined in S132 that the sheet is not being read, the time for the sheet to be conveyed from the optical sensor 111 to the pickup roller 4 is calculated from the peripheral speed of the pickup roller 4, and only that time is calculated. It may be configured such that the document table 1 is raised after waiting. By doing so, it is possible to reduce the load on the sheet while improving the throughput of sheet conveyance.

[Fifth Embodiment]
Next, using a fifth embodiment, a mode for preventing vibration of the unit to which the optical sensor 111 is attached will be described with reference to FIGS. 15 and 16. FIG. Since the basic configuration of the document feeder 200 is the same as that of the first embodiment, the description will focus on the differences from the first embodiment. Also, the control of the optical sensor 111 is as described in the first, third, and fourth embodiments.

The upper opening/closing unit 201 is a portion surrounded by the discharge stacking section 44 and the upper portion of the conveying path. The upper opening/closing unit 201 is composed of the discharge stacking section 44, the optical sensor 111, the pickup roller 4, the document feeding roller 6, the upper guide plate 40, the image reading sensor 14 on the upper side, and the like. The upper opening/closing unit 201 is rotatably fixed to a housing (main unit) by a hinge 202 on the downstream end side of the transport path. The upper opening/closing unit 201 is in a closed state as shown in FIG. 15 while the document is being conveyed.

Conversely, if the document remains in the transport path due to a jam or the like, the upper opening/closing unit 201 moves about the hinge 202 to the position indicated by the dotted line in FIG. Similarly, the upper opening/closing unit is also opened for cleaning work to remove paper powder and dust deposited on the conveying path. FIG. 18 is a schematic diagram of the upper opening/closing unit 201 in the closed state, and is a schematic diagram of the upper opening/closing unit 201 viewed downward from the upper side (discharge stacking section 44 side) of the document conveying device 200 . Therefore, the document is conveyed from the lower side to the upper side in FIG.

Holding members 212 and 213, which are resin members, from left and right side plates 210 and 211 of the housing with respect to the upper opening/closing unit 201 contact and press the sides of the upper opening/closing unit 201 by holding member pressing springs 214 and 215, thereby closing the upper opening/closing unit 201. is maintained. Here, the opening/closing operation of the upper opening/closing unit 201 is a user's manual operation, and the opening/closing operation may be performed automatically or semi-automatically, and the opening/closing method is not particularly limited. In this embodiment, the holding members 212 and 213 are provided via the holding member pressing springs 214 and 215, but this is not necessarily the case. The upper opening/closing unit 201 may be sandwiched by sliding contact between the left and right side plates 210 and 211 of the housing 212 and 213 .

Now consider the arrangement of the optical sensor 111 . Since the purpose of the optical sensor 111 is to quickly detect an abnormal transport state of the document, it is desirable that the optical sensor 111 be located on the upstream side of the transport, ideally near the paper feed port (see the lower side in FIG. 18). preferably placed). On the other hand, the optical sensor 111 is attached to the upper opening/closing unit 201 . The upper opening/closing unit can be opened/closed with the hinge 202 as the center of rotation. Here, considering the optical sensor 111 again, the optical sensor 111 detects the abnormal transport state of the document by detecting the movement amount (displacement amount) of the document at the opposing position. If the position of the member to which the optical sensor 111 is attached changes due to the vibration of the apparatus itself at this detection timing, erroneous detection data obtained by adding not only the amount of displacement of the document but also the amount of change in the position of the optical sensor 111 is acquired. will be lost.

In other words, it is desirable that the optical sensor 111 is completely fixed to the conveying surface in both the height direction and the left-right direction. From this condition, it is desirable to arrange the optical sensor 111 in a place where the upper opening/closing unit 201 is less likely to vibrate. It is easily conceivable that vibration is least likely to occur in the upper opening/closing unit 201 near the hinge 202 which is the center of rotation.

However, as described above, it is preferable for the optical sensor 111 to monitor the transport state of the document being transported on the upstream side of transport, rather than arranging it near the hinge 202 on the downstream side of transport. Side placement is preferred. As shown in FIG. 18, in the upstream of the transport path (lower side in FIG. 18), a straight line connecting the left and right holding members 214 and 215 restricting the movement of the upper opening/closing unit 201 (see FIG. 18). Dotted line) is a place where vibration is less likely to occur. Based on these facts, the optical sensor 111 is arranged on a line connecting the holding members 214 and 215 .

As described above, even when the optical sensor 111 is arranged in the upper opening/closing unit 201 that can be opened and closed freely, it can be arranged upstream of the conveying path while suppressing the influence of the vibration of the upper opening/closing unit 201. It is possible to suitably monitor the transport state of the document while suppressing the influence of vibration on the amount of displacement of the document.

In addition, since the influence of vibration is reduced, it is possible to shorten the control waiting time between stopping and restarting reading of the optical sensor 111 during the time when the influence of vibration is assumed, and shortening the non-detection time of the optical sensor 111. It becomes possible to For example, it is possible to detect the amount of displacement of the document by the optical sensor 111 while moving the paper feed unit.

Here, although the holding members 214 and 215 are resin members, this is an example, and they may be metal instead of resin. Any member may be used as long as it has such rigidity that it does not deform when pressed against the upper opening/closing unit 201 . Also, an example is shown in which the holding members 214 and 215 are attached to the left and right side plates 210 and 211 of the housing to press and regulate the upper opening/closing unit 201 . Conversely, the holding members 214 and 215 may be attached to the upper opening/closing unit 201 to press the left and right side plates 210 and 211 of the housing to restrict the movement of the upper opening/closing unit.

[Sixth embodiment]
Next, using a sixth embodiment, a mode for preventing vibration of the unit to which the optical sensor 111 is attached will be described with reference to FIGS. 19 and 20. FIG. Note that the basic configuration of the document conveying device 200 is the same as in the first and fifth embodiments. Also, the control of the optical sensor 111 is as described in the first, third, and fourth embodiments.

Protrusive members 216 and 217 (holding members) for locking are provided on left and right side plates 210 and 211 (left and right side members) of the housing. On the side of the upper opening/closing unit 201, lock members 218 and 219 are arranged at such positions that they engage with the locking protrusions 216 and 217 when the upper opening/closing unit 201 is closed. The lock members 218 and 219 are configured to interlock with an opening/closing lever 220 provided on the upper opening/closing unit 201 .

When the opening/closing lever 220 is pulled (the state shown in FIG. 20(b)), the lock member 219 is moved in conjunction with the opening/closing lever 220 to a position where it does not engage with the locking convex member 217 . On the other hand, when the opening/closing lever 220 is released (the state shown in FIG. 20(a)), the lock member 219 advances to a position where it engages with the locking convex member 217 in conjunction with the opening/closing lever 220 . A spring (not shown) applies a force to the lock member 219 in a direction opposite to the direction of releasing the fitted state so as to maintain the fitted state.

By placing the optical sensor 111 on the line connecting the lock members 218 and 219 provided on the left and right sides of the upper opening/closing unit 201, it is possible to further suppress the influence of the vibration of the upper opening/closing unit 201. FIG. In this embodiment, the optical sensor 111 is arranged on a line segment connecting the left and right locking convex members 217 as locking positions of the locking members 218 and 219 .

As described above, even if the optical sensor 111 is attached to an openable unit, it can be arranged upstream of the transport path and the vibration of the unit itself can be suppressed. can be suppressed. In addition, since the influence of vibration is reduced, it is possible to shorten the control waiting time between stopping and restarting reading of the optical sensor 111 during the time when the influence of vibration is assumed, and shortening the non-detection time of the optical sensor 111. It becomes possible to

[Seventh embodiment]
Next, using the seventh embodiment, a method of mounting the optical sensor 111 will be described with reference to FIGS. 21, 22, and 23. FIG. Note that the basic configuration of the document conveying device 200 is the same as that of the first embodiment. Also, the control of the optical sensor 111 is as described in the first, third, and fourth embodiments.

The optical sensor 111 is desirably located closer to the paper feed port in order to detect transport abnormalities in the document being transported. For example, it is located near the pickup roller 4 . Here, the pickup roller 4, the pickup motor 5, and the pickup lifting motor 250 constitute a sheet feeding unit 180 configured as a unit. The paper feed unit 180 is fixed to the lower side of the upper opening/closing unit 201, ie, the transport path side, with screws or the like via the paper feed unit holding member 252. As shown in FIG.

Here, as an example of a fixing method, it may be fixed by fitting it to the upper opening/closing unit without using screws. In other words, as long as the paper feeding unit 180 is positionally fixed with respect to the upper opening/closing unit 201, the fixing method does not matter. Alternatively, the sheet feeding unit 180 may be directly fixed to the upper opening/closing unit 201 without using the sheet feeding unit holding member 252 . That is, the paper feed unit 180 may also serve as the paper feed unit holding member 252 .

Here, since the optical sensor 111 is located near the pickup roller 4, arranging it in the paper feed unit 180 is the simplest configuration of the apparatus. However, since the paper feed unit 180 including the pickup roller 4 is affected by vibration due to vertical movement of the pickup roller 4, erroneous detection due to vibration may occur if the optical sensor 111 is arranged in the same unit. Therefore, the substrate 100 including the optical sensor 111 is not directly attached to the paper feed unit 180 and the paper feed unit holding member 252, but is mounted on the upper side of the upper opening/closing unit 201, that is, by using the optical sensor holding member 251 (imaging element fixing member). By fixing to the paper tray 44 side with screws or the like, it is attached to the upper opening/closing unit 201 so as not to come into contact with the paper feed unit 180 and a paper feed unit holding member (not shown).

As described above, the document is not directly affected by vibrations from the paper feed unit 180 and the holding member including the pickup roller 4 and the like, and the optical sensor 111 can detect the amount of displacement of the document, which enables more stable determination. Become. In addition, since the influence of vibration is reduced, it is possible to shorten the control waiting time between stopping and restarting reading of the optical sensor 111 during the time when the influence of vibration is assumed, and shortening the non-detection time of the optical sensor 111. It becomes possible to

Here, an example is shown in which the paper feed unit 180 is fixed to the upper opening/closing unit 201 via the paper feed unit holding member 252 with screws. Here, the method of fixing the paper feeding unit 180 to the upper opening/closing unit 201 does not have to be screws. you can In other words, as long as the paper feeding unit 180 is fixed to the upper opening/closing unit 201, any fixing method is applicable. Further, although the sheet feeding unit 180 is fixed to the upper opening/closing unit 201 via the sheet feeding unit holding member 252 here, a part of the sheet feeding unit 180 may also serve as the sheet feeding unit holding member 252 .

The same applies to fixing the optical sensor 111 to the optical sensor holding member 251 and the upper opening/closing unit 201 . The optical sensor 111, the optical sensor holding member 251, and the upper opening/closing unit 201 may be fitted and fixed to each other. In other words, as long as the position of the optical sensor 111 is fixed with respect to the upper opening/closing unit 201, the fixing method does not matter. Also, although the optical sensor holding member 251 is used here, a part of the optical sensor 111 may also serve as the optical sensor holding member 251 .

Here, the substrate 100 including the optical sensor 111 is attached to the upper opening/closing unit 201 using the optical sensor holding member 251, but a part of the optical sensor holding member 251 may be made of anti-vibration rubber. For example, as shown in FIG. 24, the optical sensor holding member 251 may be an optical sensor holding member 251 in which a cushioning member such as an anti-vibration rubber 253 is placed on the surface in contact with the optical sensor holding member 251 made of resin and the upper opening/closing unit 201 . By suppressing or attenuating the vibration transmitted from the upper opening/closing unit 201 with anti-vibration rubber or the like, the amount of displacement can be detected by the optical sensor 111 more stably. In this example, anti-vibration rubber is used, but there is no particular limitation, and any material such as a bumper or spring may be used as long as it is a cushioning member that can prevent shock and vibration from being transmitted from the upper opening/closing unit 201 to the optical sensor 111. No.

[Eighth embodiment]
Next, a method of attaching the optical sensor 111 and the exterior portion of the upper opening/closing unit 201 will be described using the eighth embodiment. Note that the basic configuration of the document conveying device 200 is the same as that of the first embodiment.

FIG. 25 is a partial schematic diagram of the optical sensor 111. As shown in FIG. A case body 112 (imaging element exterior material) is provided for the substrate 100 on which the optical sensor 111 is mounted so as to surround the optical sensor 111 . The case body 112 is provided to eliminate external light that disturbs the optical sensor.

The optical sensor 111 including the case body 112 is fixed inside the upper opening/closing unit 201 via the substrate 100 and an optical sensor holding member (not shown). Here, the optical sensor holding member may include the aforementioned buffer member. The optical sensor 111 is fixed to a member provided inside the upper opening/closing unit 201. However, since it is necessary to measure the amount of displacement of the document outside the upper opening/closing unit 201, the exterior of the upper opening/closing unit 201 is removed. An opening facing the optical sensor 111 is provided in the opening/closing unit exterior member 151 .

Here, the opening provided in the opening/closing unit exterior member 151 is opened so as not to interfere with the optical sensor including the optical sensor 111, the case body 112, and the optical sensor holding member. If the opening interferes with the optical sensor, the impact/vibration applied to the opening/closing unit exterior member 151 of the upper opening/closing unit 201 will propagate the vibration to the optical sensor 111 . In this embodiment, since the openings do not interfere with each other, the impact/vibration applied to the opening/closing unit exterior member 151 does not directly propagate to the optical sensor 111 . is not affected.

[Ninth Embodiment]
Next, the arrangement of the optical sensor 111 and the double feed detection sensor 30 will be described using the ninth embodiment. Note that the basic configuration of the document conveying device 200 is the same as that of the first embodiment.

The double feed detection sensor 30 is fixed to the upper opening/closing unit 201 at the downstream side of the paper feed port, which is the rear side of the feed roller 6 in FIG. The double-feed detection sensor 30 is a detection device using an ultrasonic transmission/reception unit, and detects double-feed based on the attenuation of ultrasonic waves between transmission and reception across the transport path. Here, an ultrasonic sensor is used for transmission of ultrasonic waves, and ultrasonic waves are oscillated by a piezoelectric effect caused by voltage application. Also, the receiving side outputs the received ultrasonic wave as a voltage signal by the piezoelectric effect. For this reason, the double feed detection sensor 30 on the transmission side constantly vibrates during transport.

When this vibration propagates to the optical sensor 111, the optical sensor 111 receives displacement due to vibration other than the amount of displacement of the document, and thus erroneously measures the amount of displacement. Therefore, the double feed detection sensor 30 is not mounted on the substrate on which the optical sensor 111 is mounted. In other words, the substrate on which the optical sensor 111 is mounted and the substrate on which the double feed detection sensor 30 is mounted are different substrates. As a result, it is possible to more accurately measure the amount of document displacement without being affected by the double-feed detection sensor 30 .

Also, the substrate on which the optical sensor 111 is mounted and the substrate on which the double feed detection sensor 30 is mounted may be fixed to the upper opening/closing unit 201 by separate holding members. As a result, the optical sensor 111 is less likely to be affected by vibrations from the double feed detection sensor 30 . In addition, since the influence of vibration from the double feed detection sensor 30 is reduced, it is possible to shorten the control waiting time for the optical sensor 111 to stop and resume reading during the time when the influence of vibration is expected. 111 non-detection time can be shortened.

Further, the double-feed detection sensor 30 oscillates the ultrasonic wave from the transmitting side ultrasonic sensor across the conveying path, and is attenuated by the document or the like in the conveying path and is input to the receiving side ultrasonic sensor. Therefore, the vibration of the ultrasonic sensor on the receiving side is relatively smaller than that on the transmitting side. For example, if the optical sensor 111 is installed in the upper opening/closing unit 201, the receiving ultrasonic sensor is installed in the upper opening/closing unit 201, and the transmitting ultrasonic sensor is installed in the housing on the opposite side of the transport path. , the optical sensor 111 becomes less susceptible to ultrasonic waves. In other words, by providing an oscillation-side ultrasonic sensor in a housing facing the unit to which the optical sensor 111 is attached, the optical sensor 111 is less susceptible to vibrations from the double feed detection sensor 30. Become.

Although the document conveying apparatus of the present invention has been described in detail above, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the gist of the present invention.

To summarize the present invention described above, the document conveying device according to one embodiment can be summarized as follows.
a manuscript table on which a manuscript is placed;
a transport unit for transporting the document along the transport path;
a movement amount detection unit that detects the amount of movement of the document based on an image acquired by an imaging device that receives light reflected by the document and photoelectrically converts the light;
a paper feed unit that feeds the document from the document platen;
a paper feed unit movement control unit that moves the paper feed unit between a paper feed state and a retracted state;
The movement amount detecting section is controlled so as not to detect the amount of movement of the document while the sheet feeding unit movement control section is moving the sheet feeding unit and immediately after that.

In another aspect, the document conveying device includes:
a manuscript table on which a manuscript is placed;
a transport unit for transporting the document along the transport path;
a movement amount detection unit that detects the amount of movement of the document based on an image acquired by an imaging device that receives light reflected by the document and photoelectrically converts the light;
a paper feed unit that feeds the document from the document platen;
a paper feed unit movement control unit for moving the paper feed unit between a paper feed state and a retracted state;
The sheet feeding unit movement control section controls the sheet feeding unit not to move immediately before and during the detection by the movement amount detecting section.

That is, when the paper feed unit is moved by the paper feed unit movement control section and immediately after that, the optical sensor is configured with respect to the paper feed unit that is moved so as to switch between the paper feed state and the retracted state. By not detecting the movement amount of the document by the movement amount detection unit, it is possible to stabilize the detection of the movement amount of the document.

The sheet feeding unit includes the sheet stacking table 1 and the pickup roller 4, but the present invention is not limited to this, and includes a driving unit capable of switching between a feeding state and a retracted state when feeding a document. be Examples of the sheet feeding unit movement control section include a sheet stacking table drive motor 2 that controls the movement of the sheet stacking table 1 and its control section, a pickup elevation motor 250 that controls the elevation of the pickup roller 4, and a pickup roller elevation control section. .

1 sheet stacking table 1a sheet stacking surface 2 sheet stacking table drive motor 3 sheet detection sensor 4 pickup roller 5 pickup roller drive motor 6 feed roller 7 separation roller 8 feed motor 9 separation motor 10 conveying motor 11 nip gap adjusting motor 12 sheet Stacking detection sensors 14, 15 Image reading sensors 17, 18 Registration roller 19 Registration clutches 20, 21, 22, 23 Conveying roller 30 Double feed detection sensor 32 Pre-registration sensor 33 Post-registration sensor 40 Upper guide plate 41 Lower guide plate 42 Separation roller pair (document separator)
44 discharge stacking unit 100 substrate 101 document feeding unit 102 light source 111 optical sensor 112 case body

Claims (11)

a manuscript placing table for placing a manuscript;
a transport unit for transporting the document along the transport path;
a movement amount detection unit that detects a movement amount of the document being conveyed by the conveying unit based on an image acquired by an imaging device that receives light reflected by the document and photoelectrically converts the light;
a paper feed unit that feeds the document from the document table;
a sheet feeding unit movement control section for repeatedly moving the sheet feeding unit between a sheet feeding state and a retracted state while the document is being conveyed by the conveying section;
The paper feed unit has a pickup roller for feeding the document from the document table,
The pickup roller continues to rotate until the document reaches the transport unit,
The movement amount detection section does not detect the movement amount when the sheet feeding unit movement control section moves the sheet feeding unit and immediately after that while the document is being conveyed by the conveying section. document feeder. The paper feed unit includes a pickup roller elevation control unit that raises and lowers the pickup roller between a paper feed state and a retracted state,
2. The document conveying apparatus according to claim 1, wherein the movement amount detection section does not detect the movement amount while the pickup roller elevating control section is raising and lowering the pickup roller and immediately after that. The paper feeding unit includes a document platen movement control section that controls the movement of the document table between a paper feeding state and a retracted state,
3. The document conveying apparatus according to claim 1, wherein the movement amount detection section does not detect the movement amount while the document platen movement control section is moving the document table and immediately after that. . a manuscript placing table for placing a manuscript;
a transport unit for transporting the document along the transport path;
a movement amount detection unit that detects a movement amount of the document being conveyed by the conveying unit based on an image acquired by an imaging device that receives light reflected by the document and photoelectrically converts the light;
a paper feed unit that feeds the document from the document table;
a sheet feeding unit movement control section for repeatedly moving the sheet feeding unit between a sheet feeding state and a retracted state while the document is being conveyed by the conveying section;
The paper feed unit has a pickup roller for feeding the document from the document table,
The pickup roller continues to rotate until the document reaches the transport unit,
In the control for repeatedly moving the paper feed unit while the document is being transported by the transport section, the paper feed unit movement control section controls the movement of the paper feed unit immediately before and during detection of the movement amount by the movement amount detection section. A document conveying device characterized by not moving a paper feeding unit. The paper feed unit includes a pickup roller elevation control unit that raises and lowers the pickup roller between a paper feed state and a retracted state,
5. The document conveying apparatus according to claim 4, wherein the pickup roller elevation control section does not raise or lower the pickup roller immediately before and during detection of the movement amount by the movement amount detection section. The paper feeding unit includes a document platen movement control section that controls the movement of the document table between a paper feeding state and a retracted state,
6. The document conveying apparatus according to claim 4, wherein the document platen movement control section does not move the document table included in the sheet feeding unit immediately before and during the detection by the movement amount detecting section. . a manuscript placing table for placing a manuscript;
a transport unit for transporting the document along the transport path;
a movement amount detection unit that detects the amount of movement of the document based on an image acquired by an imaging device that receives light reflected by the document and photoelectrically converts the light;
a paper feed unit that feeds the document from the document table;
a paper feed unit movement control unit that moves the paper feed unit between a paper feed state and a retracted state;
a main unit having a transport surface forming the lower surface of the transport path;
an opening/closing unit that constitutes the upper surface of the transport path and can be opened and closed by rotating around a hinge with respect to the main unit;
left and right side members provided in the main body unit and covering the left and right sides of the opening and closing unit when the opening and closing unit is in a closed state with respect to the main body unit;
a pair of holding members respectively provided on the left and right side members for holding the opening/closing unit in contact with the opening/closing unit when the opening/closing unit is closed;
the imaging element is arranged on a line segment connecting the pair of holding members;
The document conveying apparatus, wherein the movement amount detection section does not detect the movement amount while the sheet feeding unit movement control section is moving the sheet feeding unit and immediately after that. 8. The original conveying apparatus according to claim 7, further comprising a locking member provided in said opening/closing unit and abutting against said holding member. an imaging element substrate on which the imaging element is mounted;
an imaging device fixing member for fixing the imaging device substrate to the opening/closing unit;
9. The image pickup device fixing member according to claim 7, wherein the image pick-up device fixing member is provided so as not to come into contact with the paper feed unit and the paper feed unit holding portion that fixes the paper feed unit to the opening/closing unit. Document feeder. an imaging element exterior material covering the imaging element;
an opening/closing unit exterior member constituting an exterior of the opening/closing unit;
The imaging element is fixed to a member provided inside the opening/closing unit exterior member,
10. The document conveying apparatus according to claim 7, wherein the opening/closing unit exterior member has an opening formed so as not to interfere with the imaging element exterior member. an imaging element substrate on which the imaging element is mounted;
an imaging device fixing member for fixing the imaging device substrate to the apparatus main body,
8. The document conveying apparatus according to claim 7, wherein a buffer member is provided between said imaging element substrate and said imaging element fixing member.

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