JP2016169104A - Feeding device, control method, and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve detection accuracy of a feeding abnormality.SOLUTION: A feeding device of the present invention comprises: sheet loading means on which sheets are loaded; feeding means which feeds the sheets loaded on the sheet loading means; deformation detection means which detects deformation of the sheets fed by the feeding means; skew detection means which detects skew of the sheets fed by the feeding means; and determination means which determines whether or not a feeding abnormality occurs on the basis of the detection result of the deformation detection means and the detection result of the skew detection means.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a feeding device.

  A feeding device that automatically feeds sheets such as paper sequentially feeds sheets stacked on a sheet stacking table one by one. The sheet bundle loaded on the sheet loading table is premised on individual sheets being separated. However, there are cases where a bundle of sheets bound by stapling, clipping, gluing, or the like is stacked due to carelessness of the user. When the sheet feeding operation is performed from such a sheet bundle, the sheet may be wrinkled or damaged, or a paper jam may occur in the feeding apparatus.

  When a sheet is fed from a bound sheet bundle, the sheet tends to be deformed, for example, rotated so as to roll up around the bound portion. In view of this, Japanese Patent Application Laid-Open No. 2004-151867 discloses an apparatus that detects a sheet feeding abnormality by detecting a deformation amount of a sheet, in particular, a change in sheet bounce.

Japanese Patent No. 4663176

  The sheets stacked on the sheet stacking table may be curled or creased. In such a case, the sheet can be fed without causing damage to the sheet. In the case of a method in which a sheet deformation amount is detected by detecting the deformation amount of the sheet, there is a case where even if the sheet bundle is not spelled, a sheet curl or the like is detected and it is determined that the sheet is abnormal. As a countermeasure, it is conceivable to adjust the threshold value for determining the abnormal feeding and determine that the abnormal feeding occurs when the deformation amount of the sheet becomes larger. However, the timing at which it is determined that the feeding is abnormal is likely to be delayed, and there is a case where a sheet is damaged or a paper jam has already progressed at the time of determination.

  An object of the present invention is to improve the determination accuracy of feeding abnormality.

  According to the present invention, for example, a sheet stacking unit on which sheets are stacked, a feeding unit that feeds sheets stacked on the sheet stacking unit, and a deformation of a sheet fed by the feeding unit are detected. Based on the deformation detection means, the skew detection means for detecting the skew of the sheet fed by the feeding means, the detection result of the deformation detection means, and the detection result of the skew detection means. And a determination unit that determines whether or not there is a feeding abnormality.

  According to the present invention, it is possible to improve the determination accuracy of feeding abnormality.

1 is a diagram illustrating an example of an image reading apparatus to which the present invention is applied. FIG. 2 is a schematic diagram of a part of the configuration of the image reading apparatus in FIG. 1. (A) is a figure which shows the example of the sheet | seat bundle | flux bound by the staple, (B) is a figure which shows the example at the time of feeding a sheet | seat from the sheet | seat bundle of FIG. 3 (A). (A) is a schematic diagram showing a part of the image reading apparatus of FIG. 1, (B) is an explanatory view of a deformation detection sensor. Explanatory drawing of a skew detection sensor. The block diagram of a control part. The flowchart which shows the process example of a control part. 6 is a timing chart showing changes in sheet conveyance amount, skew feeding amount, deformation amount, and determination threshold value. The flowchart which shows the process example of a control part. 6 is a timing chart showing changes in sheet conveyance amount, skew feeding amount, deformation amount, and determination threshold value. 6 is a timing chart showing changes in sheet conveyance amount, skew feeding amount, deformation amount, and determination threshold value. Explanatory drawing of the skew detection sensor of another example. FIGS. 6A to 6C are diagrams illustrating examples of changes in the rotation amount of a sheet. FIGS. 9 is a timing chart showing changes in sheet conveyance amount, skew feeding amount, deformation amount, rotation amount, and determination threshold value. (A) And (B) is explanatory drawing of the deformation | transformation detection sensor of another example. The flowchart which shows the process example of a control part. Explanatory drawing of the skew detection sensor of another example.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In each drawing, an arrow X indicates a sheet feeding direction, and an arrow Y indicates a direction intersecting with the feeding direction (here, an orthogonal direction and a sheet width direction). An arrow Z indicates a direction orthogonal to the X direction and the Y direction, and in the case of the present embodiment, it is the sheet stacking direction. In the following description, the terms “upstream side” and “downstream side” mean the upstream side and the downstream side in the feeding direction unless otherwise specified. In the following description, it is assumed that the sheet to be fed is paper, but the present invention can also be applied to feeding sheets other than paper. In addition, the sheet feeding and feeding direction may be referred to as sheet conveyance and conveyance direction. Furthermore, in the following description, the terms “left” and “right” refer to the left and right in the sheet feeding direction unless otherwise specified, in other words, one of the other in the width direction of the sheet.

<First embodiment>
FIG. 1 is a schematic diagram of an image reading apparatus 200 according to an embodiment of the present invention, and FIG. 2 is a schematic diagram of a part of the configuration of the image reading apparatus 200. The image reading device A is a scanner that reads an image on a sheet and digitizes it, and is configured by applying a feeding device according to an embodiment of the present invention.

  Note that the feeding device of the present invention can be applied to devices other than the image reading device, for example, an image recording device that forms an image on a sheet. Further, for example, the present invention can be applied to a post-processing apparatus that binds sheets or punches holes. Further, the feeding device of the present invention may be incorporated in a device to which a sheet is supplied or may be configured as a separate body.

  The image reading device 200 is a device that feeds a sheet with the feeding device 101 and reads an image of the fed sheet. The conveyance motor 10 drives each roller in order to convey the fed sheet from the image reading position to the discharge position. Further, the conveyance motor 10 drives each roller so that the sheet conveyance speed can be changed according to the optimum speed for reading the sheet, the resolution of the sheet, and the like.

  The image reading unit 43 includes image reading sensors 14 and 15 for reading a sheet, and can change the scanning interval based on the setting of the reading speed and resolution of the sheet. The sheet discharge sensor 16 detects that the sheet passes through the image reading unit 43 and is being discharged to the discharge stacking unit 44.

  The rotational driving force of the conveyance motor 10 is transmitted to the registration roller 18 by an unillustrated registration clutch or interrupted. By stopping the rotation of the registration roller pair 17 and 18, the leading edge of the fed sheet is abutted against the nip portion of the registration roller pair 17 and 18, and the skew of the sheet is corrected.

  The conveyance roller pairs 20 and 21, the conveyance roller pairs 22 and 23, and the downstream roller pair convey the sheet to the discharge stacking unit 44. The two guide plates of the upper guide plate 40 and the lower guide plate 41 include a separation feeding unit 42, registration roller pairs 17, 18, conveyance roller pairs 20, 21, conveyance roller pairs 22, 23, and downstream roller pairs. To guide the sheet conveyed.

  The pre-registration sensor 32 is a sheet detection sensor that is disposed on the upstream side of the registration roller pair 17 and 18 and detects a conveyed sheet. The post-registration sensor 33 is a sheet detection sensor that is disposed on the downstream side of the registration roller pair 17 and 18 and detects a conveyed sheet. As each sheet detection sensor appearing in this book, for example, a reflection type optical sensor for detecting a sheet and an optical sensor for detecting a position of a lever movable by conveying the sheet can be cited.

  The feeding device 101 includes a sheet stacking table 1, a feeding mechanism FU, a deformation detection unit 35, and a skew detection unit 61.

  A plurality of sheets (sheet bundle F) are stacked on the sheet stacking table 1. Positioning in the width direction of the sheet is performed by a guide 51 provided on the sheet stacking table 1. The sheet stacking table 1 is configured to be movable up and down. The drive motor 2 moves the sheet stacking table 1 up and down. The sheet detection sensor 3 detects the sheets stacked on the sheet stacking table 1.

  The feeding mechanism FU includes a pickup roller 4 and a separation feeding unit 42. The separation feeding unit 42 includes a feeding roller 6 and a separation mechanism 7. The pickup roller 4 is a roller for taking out the sheets stacked on the sheet stacking table 1, and sends out the sheets on the sheet stacking table 1 from the uppermost sheet to the feeding roller 6. The pickup roller drive motor 5 rotates the pickup roller 4.

  The feeding roller 6 is a roller that conveys the sheet taken out by the pickup roller 4 to the downstream side. The feeding roller 6 is driven by a feeding motor 8 so as to rotate in a direction in which the sheet is fed downstream.

  The separation mechanism 7 is pressed against the peripheral surface of the feeding roller 6 and conveys the sheets one by one. In the present embodiment, the separation mechanism 7 is a separation roller, and the separation mechanism 7 may be referred to as a separation roller 7 in the following description. The separation mechanism 7 is not limited to the separation roller, and may be another separation mechanism such as a separation pad.

  The separation roller 7 constantly receives a rotational force that rotates in a direction to push back the sheet upstream from the separation motor 9 via a torque limiter (slip clutch) (not shown). When one sheet exists between the feeding roller 6 and the separation roller 7, the feeding roller 6 is determined from the upper limit value of the rotational force in the direction of pushing back the sheet to the separation roller 7 transmitted by the torque limiter. The rotational force in the direction in which the sheet is fed downstream is greater. For this reason, the separation roller 7 rotates following the feeding roller 6. On the other hand, when there are a plurality of sheets between the feeding roller 6 and the separation roller 7, the separation roller 7 rotates in a direction to push the sheet back to the upstream side and pushes back the sheets other than the uppermost sheet.

  In this way, the feeding roller 6 feeds the sheet downstream, and the separation roller 7 pushes the sheet upstream. As a result, when the sheets are overlapped and fed into the nip portion between the feeding roller 6 and the separation roller 7, only the uppermost sheet is fed to the downstream side, and the other sheets are pushed back to the upstream side and overlapped. Sheets are fed separately. Thus, the feeding roller 6 and the separation mechanism 7 constitute a separation feeding unit 42 that feeds the sheets taken out by the pickup roller 4 one by one. Note that either the separation roller 7 or the feeding roller 6 may be a belt.

  The nip gap adjusting motor 11 adjusts a gap between the feeding roller 6 and the separation roller 7 or a pressure contact force with which the feeding roller 6 is pressed against the separation roller 7 via a 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 and fed.

  The deformation detection unit 35 detects the deformation amount of the sheet fed by the feeding mechanism FU. In the present embodiment, the deformation detection unit 35 detects the degree of jumping on the sheet stacking table 1 (the degree of deformation in the Z direction). When the sheet bundle F is fed with the staple SP1 bound as shown in FIG. 3A, the uppermost sheet 1 is rotated counterclockwise around the staple SP1 as shown in FIG. 3B. The right end of the sheet jumps up while rotating. Such deformation of the sheet is detected by the deformation detection unit 35.

  In the present embodiment, the deformation detection unit 35 includes a light emitting unit 35a and a light receiving unit 35b that are spaced apart from each other in the Y direction, as shown in FIG. The light emitting unit 35a and the light receiving unit 35b are arranged so as to sandwich the sheet bundle F on the sheet stacking table 1 in the width direction.

  In the present embodiment, the light emitting unit 35a includes a plurality of light emitting elements (for example, LEDs), and the light receiving unit 35b includes a plurality of light receiving elements (for example, phototransistors). Note that the number of light emitting elements may be one.

  The plurality of light emitting elements are arranged one-dimensionally in the vertical direction (Z direction) with respect to the sheet stacking surface 1 a of the sheet stacking table 1. The light receiving elements are provided in the same number as the light emitting elements, and are arranged to face each other so that each light receiving element and each light emitting element have a one-to-one correspondence.

  When the sheets stacked on the sheet stacking table 1 are fed, each light emitting element is turned on. And the light irradiated from each light emitting element is received by the corresponding light receiving element. In this case, the light receiving state of each light receiving element changes depending on the amount of sheet jump (the amount of deformation). That is, in the case of a set of a light emitting element and a light receiving element in which a sheet is interposed among a plurality of sets of light emitting elements and light receiving elements, the amount of received light is at least reduced. As described above, the deformation detection unit 35 can detect the deformation of the sheet in a multivalued manner based on the number of light receiving elements that receive the light emitted from the light emitting elements. Therefore, the deformation detection unit 35 can detect the deformation level of the sheet (the amount of deformation of the sheet if numerical evaluation is performed based on the number of light receiving elements) according to the state of the optical sensor output.

  For example, in the present embodiment, the number of light emitting elements and light receiving elements is four, and the deformation amount of the sheet is detected in five stages of 0 to 4. Whether or not the sheet is abnormally fed is determined according to the deformation amount and the skew amount of the sheet detected by the skew detection unit 61.

  The skew detection unit 61 detects the skew amount at the leading end (downstream end) of the fed sheet. As shown in FIG. 5, the skew detection unit 61 includes two sheet detection sensors 61 </ b> R and 61 </ b> L that are disposed on the downstream side of the separation / feed unit 42 and are spaced apart from each other in the Y direction.

  In the present embodiment, the skew amount is calculated from the difference between the detection timings of the two sheet detection sensors 61R and 61L. When the sheet bundle F is bound with staples or the like, skew feeding occurs during separation of sheets by the separation feeding unit 42. The skew detection unit 61. The amount of skew feeding can be calculated from the detection timing of the two sheet detection sensors 61R and 61L assuming that the amount of movement of the feeding roller 6 that rotates by driving the feeding motor 8 is the amount of movement of the sheet. Here, the skew amount can be obtained from the difference between the detection timings of the sheet detection sensors 61R and 61L of the skew detection unit 61, but a plurality of detection sensors can be obtained without quantitatively obtaining the skew amount. The skew level based on the difference in detection timing may be determined.

  The configuration of the control unit 45 will be described with reference to FIG. The control unit 45 includes a CPU 451, a storage unit 452, an operation unit 453, a communication unit 454, and an interface unit 455. The CPU 451 controls the entire image reading apparatus 200 by executing a program stored in the storage unit 452. The storage unit 452 includes, for example, a RAM, a ROM, and the like. The operation unit 453 is configured with, for example, a switch, a touch panel, and the like, and receives an operation from the operator.

  The communication unit 454 is an interface that performs information communication with an external device. When a PC (personal computer) is assumed as the external device, examples of the communication unit 454 include a USB interface and a SCSI interface. In addition to such a wired communication interface, the communication unit 454 may be a wireless communication interface, and may include both wired communication and wireless communication interfaces.

  The interface unit 455 is an I / O interface that inputs and outputs data with the actuator 456 and the sensor 457. The actuator 456 includes, for example, the various motors described above. The sensor 457 includes the various sensors described above.

<Control example>
<Skew amount calculation>
An example of processing executed by the CPU 451 will be described. FIG. 7 is a flowchart showing the skew amount calculation processing. In this process, a software counter (a skew amount counter) is used to count the skew amount of the sheet. The skew amount counter takes both positive and negative values, increases or decreases the counter value according to the detection state of the skew detection unit 61, and stops increasing or decreasing the counter value when the skew amount is finally determined. The skew amount counter increases / decreases the counter so that it is positive when the right side of the sheet is the leading skew angle in plan view and negative when the left side of the sheet is the leading skew angle. The skew amount counter value is used to calculate a determination threshold value for determining abnormal sheet feeding.

  The process starts in S101. First, the skew amount counter is cleared to 0 (S102), and the process waits for a sheet to be detected by either the left or right sensor of the skew detection unit 61 (No in S103, No in S105). When the right sensor 61R of the skew detection unit 61 detects a sheet (Yes in S103), the skew amount counter starts counting up (S104). When the left sensor 61L detects a sheet (No in S103, Yes in S105), the skew amount counter starts to count down (S106). The count-up and count-down are values proportional to the rotation amount of the feeding roller 6 so that the counter value changes according to the rotation of the feeding roller 6.

  Until the sheet is detected on both the left and right sides of the skew detection unit 61 (No in S107), the skew amount counter value continues to increase or decrease according to the rotation of the feeding roller 6. When the sheet is detected on both the left and right sides of the skew detection unit 61 (Yes in S107), the count of the skew amount counter is stopped (S108). The value of the skew amount counter at this time becomes the fixed value of the skew amount at the leading end of the sheet. This completes the skew amount detection processing (S109).

<Determination of feeding abnormality>
Next, a method for determining abnormal sheet feeding will be described. When the deformation detection unit 35 detects a large amount of deformation (bounce amount or change amount) of the sheet, the sheet bundle F is spelled, and there is a high possibility of abnormal feeding. However, even if the sheet bundle F is not bound, if the sheet is curled, a large amount of sheet deformation may be detected. In this case, feeding may be performed normally. Therefore, by referring to the skew amount, the determination accuracy of the feeding abnormality is improved. In the present embodiment, a determination threshold value for the deformation amount of the sheet that is determined to be a feeding abnormality is set based on the skew feeding amount.

  FIG. 8 is a timing chart showing changes in sheet conveyance amount, skew feeding amount, deformation amount, and determination threshold. As described above, the deformation amount (bounce amount) of the sheet is set in five stages from 0 to 4, and is 0 when there is no bounce. When the jump is the largest, 4 is assumed. When the deformation amount of the sheet becomes equal to or greater than the determination threshold value, it is determined that the sheet feeding is abnormal. When it is determined that the feeding is abnormal, the feeding operation may be stopped. Moreover, you may alert | report a warning. In any case, it is possible to control so that damage due to abnormal sheet feeding does not increase.

  Note that the deformation amount in FIG. 8 shows a change in the case where the feeding is continued even after it is determined that the feeding is abnormal, so that the amount of jump is increased even after the judgment. However, when it is actually determined that the feeding is abnormal and the feeding is stopped, the jumping up is stopped.

  In FIG. 8, the skew amount at the front end of the sheet is 0 at the beginning, and after the start of feeding, here the sheet is detected by the sheet detection unit 61R, and thus increases to a positive value. The sheet detection unit 61L also detects a sheet when the skew amount is 20 mm, and the counter stops with the skew amount being 20 mm. The determination threshold is corrected according to the change in the skew amount.

  The determination threshold is set to 3 as an initial value, and is not corrected when the skew amount is 0 mm. In order to reduce the determination threshold as the skew amount increases, an offset value proportional to the skew amount is obtained and subtracted from the initial value to correct the determination threshold by the following formula.

Determination threshold = initial value−offset value This offset value is obtained as (| skew amount | / 10). Then, the judgment threshold is
Determination threshold = initial value− (| skew amount | / 10)
Asking. For example, when the initial value is 3 and the skew amount is 10 mm, the determination threshold value is 2, and the amount of jump determined to be abnormal is one step lower than the initial value.

  FIG. 9 is a flowchart showing an example of a feeding abnormality determination process by such a method. The process starts in S201. First, 3 is set as an initial value for a determination threshold value for determining a feed abnormality (S202), and the skew amount calculation process described with reference to FIG. 7 is started (S203). The skew amount calculation processing is executed in parallel. Sheet feeding is started (S204).

  The detection result of the deformation detection unit 35 is acquired, and when the deformation amount of the sheet is equal to or greater than the determination threshold value (No in S205), it is determined that the sheet feeding is abnormal. Then, the sheet feeding is stopped (S211), and the process ends abnormally (S212).

  In S205, when the deformation amount of the sheet does not reach the determination threshold value (Yes in S205), it is determined that the feeding is normal and the process is continued. Subsequently, processing regarding correction of the determination threshold is performed. The method of correcting the determination threshold is changed depending on whether or not the leading edge of the sheet has reached the post-registration sensor 33. When the leading edge of the sheet has not reached the post-registration sensor 33 (Yes in S206), the determination threshold is updated to a value calculated according to the skew amount as described above (S207). When the leading edge of the sheet has reached the post-registration sensor 33, the initial value (3) is reset as the determination threshold (S208).

  The reason why the process of S208 is executed in the case of No in S206 is as follows. That is, when the preceding sheet is skewed from the time when it is stacked on the sheet stacking table 1 and the subsequent sheet is not skewed but is curled, it is not determined that the feeding abnormality is caused in both the preceding sheet and the succeeding sheet. It is for doing so. This will be described more specifically with reference to FIG.

  It is assumed that the skew amount of the preceding sheet has increased to 15 mm. The determination threshold is reduced to 1.5. Since the deformation amount of the preceding sheet increases only to 1, the preceding sheet is not determined to be abnormal. If the end of the subsequent sheet is curled, the amount of deformation of the curl is detected when the preceding sheet is fed (the amount of deformation is 2 in FIG. 9).

  At this time, if the determination threshold value remains 1.5, it is determined that the feeding is abnormal. In order to avoid this, by returning the determination threshold to the initial value 3 when the leading edge of the preceding sheet reaches the post-registration sensor 33, the deformation amount due to curling of the subsequent sheet does not exceed the determination threshold, and the feeding abnormality It is possible to prevent erroneous determination.

  In this embodiment, S208 in FIG. 9 is processed at the timing when the leading edge of the sheet reaches the post-registration sensor 33, but may be at another timing. An appropriate timing is from the time when the leading edge of the sheet reaches the registration roller pair 17 and 18 until the trailing edge of the sheet passes the leading edge of the next sheet. For example, when the sheet size is a fixed size, the position of the trailing edge of the sheet can be grasped, and therefore the timing after a predetermined time after the leading edge of the sheet reaches the post-registration sensor 33 may be set as the timing of S208. Further, a sensor that can detect the movement of the sheet surface is provided in the vicinity of the pickup roller 4, and the timing when the trailing edge of the sheet reaches the vicinity of the pickup roller 4 may be set as the timing of S208.

  Returning to FIG. 9, the above-described processing is continued until the trailing edge of the sheet passes the pre-registration sensor (No in S209). When the trailing edge of the sheet passes the pre-registration sensor (Yes in S209), the sheet feeding ends. Then, the process ends normally (S210).

  As described above, in the present embodiment, the feeding abnormality is determined based on the detection result of the deformation amount of the sheet and the detection result of the skew amount of the sheet. In a sheet bound by staples or the like, the skew feeding amount of the sheet becomes large. Therefore, an abnormality can be determined at an early stage by increasing the reduction correction amount of the feeding abnormality determination threshold.

  On the other hand, in a normal sheet without staples, even a sheet whose sheet end is curled up can be fed without being determined as feeding abnormality. FIG. 11 is a timing chart showing changes in sheet conveyance amount, skew feeding amount, deformation amount, and determination threshold when a curled up sheet is fed. Since the sheet has already springed up due to curling, the deformation amount is always 1-2. However, since the skew amount of the sheet is small, the reduction correction amount of the determination threshold is small, and it is not determined that the conveyance is abnormal. Therefore, it can feed normally.

  Further, by arranging a sensor for detecting the amount of skew of the sheet on the downstream side of the separation / feed unit 42, the skew that occurs when the sheets bound by staples are separated by the separation / feed unit 42 is detected. be able to.

  In the present embodiment, the two sheet detection sensors 61L and 61R of the skew detection unit 61 are disposed on the downstream side of the separation feeding unit 42, but may be disposed at other positions. For example, the two sheet detection sensors 61L and 61R may be arranged on the left and right so as to sandwich the separation feeding unit 42. As shown in FIG. 17, the position in the transport direction is arranged near the downstream end of the nip region (the thick line portion in FIG. 17) between the feeding roller 6 and the separation roller 7. If the sheets bound with staples are strong, skewing occurs at an early stage after separation of the sheets, but skewing can be detected early with this sensor arrangement.

<Second embodiment>
In the first embodiment, two sheet detection sensors are provided on the left and right sides as the skew detection unit 61, but the number and arrangement of the sensors are not limited thereto. FIG. 12 shows an example. In the example of FIG. 12, three sets of sheet detection sensors are arranged apart from each other in the feeding direction. The sheet detection sensors 61L and 61R (hereinafter also referred to as a set of sensors 61) are disposed in the vicinity of the nip region of the separation feeding unit 42. The sheet detection sensors 62L and 62R (hereinafter also referred to as a set of sensors 62) are disposed on the downstream side of the sheet detection sensors 61L and 61R. The sheet detection sensors 63L and 63R (hereinafter also referred to as a set of sensors 63) are arranged on the downstream side of the sheet detection sensors 62L and 62R. Three sets of sheet detection sensors respectively detect the skew amount from the difference in detection timing of the sheet leading edge. Thereby, the skew amount can be detected at three detection positions different in the feeding direction. Two examples of how to use the three skew amounts per detection position detected by the three sheet detection sensors will be described.

In the first usage method, the correction amount (offset value) of the determination threshold is calculated as a correction candidate amount from the three skew feed amounts detected by the three sets of sheet detection sensors, and the maximum value of the correction candidate amounts is finally determined. Offset value. In this case, the correction candidate amount is set to be larger in the downstream detection position with respect to the same skew amount. As a result, even if the occurrence of skew of the sheet is delayed, the feeding abnormality can be detected more reliably. The second usage method is based on the three skew amounts detected by the three sets of sheet detection sensors. Find the amount of rotation. Then, a correction amount (offset value) of the determination threshold is calculated based on the rotation amount. The rotation amount of the sheet is the rotation amount of the difference between the two skew amounts detected by the sensor 61 group and the sensor 62 pair, and the difference between the two skew amounts detected by the sensor 62 group and the sensor 63 pair. Calculate the amount of rotation.

  A method for calculating the amount of rotation of the sheet will be described with reference to FIGS. The amount of skew detected by the set of sensors 61 is set as the amount of skew 1 and the amount of skew detected by the set of sensors 62 is set as the amount of skew 2. The amount of rotation obtained from the amount of skew 1 and the amount of skew 2 is the amount of rotation. Set to 1. There are three types of combinations of the magnitude of the skew amount 1 and the skew amount 2 and the difference in the sign, as shown in FIGS. 13A to 13C, and the timing for starting the calculation of the rotation amount is different.

  In FIG. 13A, the skew amount 1 and the skew amount 2 have the same sign, and | the skew amount 1 | ≦ | the skew amount 2 |. In the figure, the sign indicates a positive case. In this case, when | skew amount 1 | ≦ | skew amount 2 | is satisfied, skew amount 2−skew amount 1 is calculated as the rotation amount.

  In FIG. 13B, the skew amount 1 and the skew amount 2 have the same sign, and | skew amount 1 |> | skew amount 2 |. In the figure, the sign indicates a positive case. In this case, after the value of the skew amount 2 is determined, the skew amount 2−the skew amount 1 is calculated as the rotation amount.

  FIG. 13C shows a case where the skew amount 1 and the skew amount 2 have different signs. In this case, the skew amount 2−the skew amount 1 is calculated as the rotation amount after the sign of the skew amount 2 is determined to be positive or negative.

  The rotation amount of the difference between the two skew amounts detected by the sensor 61 group and the sensor 62 has been described above. However, the rotation of the difference between the two skew amounts detected by the sensor 62 group and the sensor 63 pair has been described. The amount is similar.

  A process for determining a sheet feeding abnormality with reference to the rotation amount calculated as described above will be described with reference to FIG. The skew amount detected by the set of sensors 63 is defined as a skew amount 3, and the rotation amount obtained from the skew amount 2 and the skew amount 3 is defined as a rotation amount 2. Further, in the present embodiment, it is assumed that the deformation detection unit 35 includes 8 light emitting elements and 8 light receiving elements, and the deformation amount (bounce amount) of the sheet can be detected in 9 stages of 0 to 8.

If the value for reducing the determination threshold based on the rotation amount 1 is an offset value 1,
Offset value 1 = | Rotation amount 1 | / 5
The determination threshold is calculated as an initial value-offset value 1.

Next, when the value for reducing the determination threshold for the rotation amount 2 is an offset value 2,
Offset value 2 = | Rotation amount 2 | / 3
Calculate as The offset value 2 is larger than the offset value 1 for the same rotation amount of the sheet. The more the sheet is located on the downstream side in the conveyance direction with respect to the same rotation amount of the sheet, the higher the probability that the feeding will be abnormal. Therefore, the offset value 2 is increased. Further, when the offset value 2 becomes larger than the offset value 1, the offset value 2 is applied to the determination threshold value, and the determination threshold value is calculated as an initial value-offset value 2.

  In addition, the flowchart of the process in this embodiment is substantially the same as FIG. 9 demonstrated in 1st embodiment. The difference is that the rotation amount is used in place of the skew amount in S207, and 7 is used as the initial value of the determination threshold in S202 and S208.

  In the present embodiment, a plurality of sets of sheet detection sensors are provided in the feeding direction, and the skew amount of the sheet is detected at a plurality of detection positions different in the sheet feeding direction. Further, the reduction amount of the determination threshold is increased with respect to the skew amount detected on the downstream side. For this reason, even if the occurrence of skew of the sheets bound with staples during the separate feeding is delayed, it is possible to detect the feeding abnormality more reliably.

  In addition, by correcting the determination threshold according to the rotation amount of the sheet, even when the sheet is tilted before separation and feeding, it is possible to more reliably detect a feeding abnormality caused by a sheet bundle bound by staples or the like. Can do.

  In the present embodiment, the skew detection unit 61 includes three sets of sheet detection sensors, but two sets or four sets may be abnormal. Even in the case of two sets, one sheet rotation amount can be obtained. Further, if there are four or more sets, the weighting of the offset value for reducing the determination threshold can be set finely, and the sheet abnormality can be determined more flexibly.

<Third embodiment>
Another example of the deformation detection unit 35 will be described. FIGS. 15A and 15B are explanatory diagrams thereof. In the present embodiment, the deformation detection unit 35 includes a left region detection unit 36 and a right region detection unit 37. The left area detection unit 36 detects the deformation amount of the left area of the pickup roller 4 when viewed in the sheet feeding direction. The right area detection unit 37 detects the deformation amount of the area on the right side of the pickup roller 4 when viewed in the sheet feeding direction.

  The left area detection unit 36 is disposed near the left side of the sheet stacking table 1. The left area detection unit 36 has one light emitting element 36 a and irradiates light toward the side surface of the pickup roller 4. The light irradiated toward the pickup roller 4 is reflected by the side surface of the pickup roller 4, and the reflected light is received by the plurality of light receiving elements 36b.

  The plurality of light receiving elements 36b are arranged in the Z direction below the light emitting elements 36a. A plurality of optical paths are formed by one light emitting element 36a and a plurality of light receiving elements 36b, and the amount of jumping can be detected in a multivalued manner according to the sheet jumping. The right region detection unit 37 is similar, and includes a light emitting element 37a and a plurality of light receiving elements 37b, and detects the jumping of the sheet. In the third embodiment, the number of light receiving elements 36a and 36b is four, and the deformation amount (bounce amount) is detected in five stages of 0 to 4.

  In the third embodiment, determination thresholds for determining an abnormality with respect to the deformation amounts on the left and right sides are set separately for the right side and the left side. Also, an offset value corresponding to the skew amount of the sheet is set separately. A determination threshold value for determining whether or not the deformation amount of the region on the left side of the sheet detected by the left region detection unit 36 is abnormal is defined as a determination threshold value L. A determination threshold value R that is determined by the right region detection unit 37 to determine whether or not the deformation amount of the right region of the sheet is abnormal is set as a determination threshold value R. And about the area | region preceded by skew feeding, a determination threshold value is set by correcting an initial value based on the detection result of skew feeding amount. On the other hand, a determination threshold value is set as an initial value for a region that does not precede.

  For example, it is assumed that the sheet detection sensor 61R first detects the leading edge of the sheet among the sheet detection sensors 61R and 61L of the skew detection unit 61. In this case, the preceding area is specified as the area on the right side of the sheet. Then, the determination threshold R is corrected according to the skew amount, and the determination threshold L is left as the initial value.

  FIG. 16 shows a process flow of sheet abnormality detection in the present embodiment. First, as an initial value of the determination threshold, 3 is set as the determination threshold R and the determination threshold L (S302, S303). The skew amount calculation processing is started (S203), and sheet feeding is started (S204). Next, the deformation amount and the determination threshold are compared separately for the left and right.

  First, if the left jump amount is greater than or equal to the determination threshold L (No in S304), or if the right jump amount is greater than or equal to the determination threshold R (No in S305), sheet feeding is stopped (S211). The process ends (S212). When the amount of leftward bounce is smaller than the determination threshold L (Yes in S304), and when the amount of rightward bounce is smaller than the determination threshold R (Yes in S305), sheet feeding is continued.

  When the leading edge of the sheet has not reached the post-registration sensor 33 (Yes in S206), when the absolute value of the skew amount of the sheet is equal to or greater than the predetermined value α, only the determination threshold value on the side where the sheet is inclined is updated. When the skew amount is α or more (No in S306), the determination threshold R is updated according to the skew amount (S308). At this time, since the determination threshold L is not changed, the initial value remains set. When the skew amount is −α or less (No in S307), the determination threshold L is updated according to the skew amount (S309). Similarly, at this time, the determination threshold R is not changed, so the initial value remains set.

  In S206, if the leading edge of the sheet has reached the post-registration sensor (No in S206), the initial value is set again for the determination threshold values on both the left and right sides (S310, S311). Thereafter, the abnormality determination and the updating of the determination threshold are repeated until the trailing edge of the sheet passes the pre-registration sensor (Yes in S209).

  In the present embodiment, for example, when the right side of the sheet is skewed ahead, the determination threshold value on the right side where the sheet is likely to jump can be reduced. For this reason, it is possible to quickly detect a feeding abnormality. Furthermore, since the left determination threshold value that is difficult to jump up is not reduced, it is possible to prevent erroneous detection of curling or edge breakage.

<Other embodiments>
The present invention is also realized by executing the following processing. That is, software (program) that realizes the functions of the above-described embodiments is supplied to a system or apparatus via a network or various storage media, and a computer (or CPU, MPU, or the like) of the system or apparatus reads the program. It is a process to be executed.

  In addition, this invention is not limited to the form mentioned above, It can apply to various forms. For example, when the sheet shape change on the sheet stacking means (mounting table) is fast and large, the sheet deformation detection means can detect the change at an early stage and immediately stop the feeding operation to prevent damage to the sheet. it can. On the other hand, if the change in the sheet shape is slow and small, if the feeding operation is stopped immediately, the feeding is actually stopped until the sheet that can be fed, so there is a risk that the feeding efficiency may be reduced. is there. Therefore, when the change in the sheet shape is slow and small in this way, it may be determined that there is no problem in feeding. For example, the feeding operation is continued as it is, or the detection of the sheet deformation detection unit is continued. Then, control the sheet deformation state, reduce the sheet feeding speed, etc., and continue the feeding operation within the range where the sheet is not damaged. It can be decided whether to stop immediately. This skew detection means can detect the deviation of the detection timing of the optical sensor if the optical sensors are arranged at a plurality of portions on both sides of the portion that exerts the separation action on the sheet, for example, the region where the sheet is sandwiched between the feeding roller and the separation roller. The skew detection can be performed using, and if the sheet being separated is skewed, the sheet can be stopped immediately before the sheet is damaged. In other words, the skew detection means is preferably provided as close as possible to the separation section that separates the sheets, and the sheet deformation detection means can detect the deformation of the sheet that occurs around the separation section that separates the sheets. It is preferable to set the periphery of as a detection area. Therefore, it is only necessary to detect the movement of the sheet (deformation and skew) before and after the sheet separation unit and determine whether to continue the sheet feeding or stop the sheet feeding according to the combination. That is, while detecting the deformation of the sheet due to the separation failure, the skew of the sheet due to the separation failure is also detected, and if the sheet breaks due to the separation failure, the sheet feeding is immediately stopped, If there is no risk of damage due to skew, continue feeding. As a result, when sheet feeding is abnormal, it is possible to immediately stop, and when sheet feeding can be continued, the immediate stop of sheet feeding can be reduced, and as a result, the efficiency of sheet feeding can be increased.

101 Feeder, FU Feeder, 35 Deformation Detection Unit, 61 Skew Detection Unit, 45 Control Unit

Claims (16)

Sheet stacking means on which sheets are stacked;
A feeding means for feeding the sheets stacked on the sheet stacking means;
Deformation detection means for detecting deformation of the sheet fed by the feeding means;
Skew detection means for detecting skew of a sheet fed by the feeding means;
Determination means for determining whether there is a feeding abnormality based on the detection result of the deformation detection means and the detection result of the skew detection means,
A feeding device characterized by that. Further comprising setting means for setting a determination threshold based on the detection result of the skew detection means;
The determination means compares the detection result of the deformation detection means with the determination threshold value to determine whether or not there is a feeding abnormality;
The feeding device according to claim 1. The setting unit sets the determination threshold by correcting a predetermined initial value based on a detection result of the skew detection unit;
The feeding device according to claim 2. The setting means sets the determination threshold value so that it is easier to determine that the sheet is abnormal as the skew amount of the sheet is larger from the detection result detected by the skew detection means.
The feeding device according to claim 2 or 3, wherein The skew detection means detects skew of the sheet fed by the feeding means at a plurality of detection positions different in the sheet feeding direction,
The setting means sets a correction amount of the initial value based on detection results detected at the plurality of detection positions;
The feeding device according to claim 3. The correction amount is likely to be determined as a feeding abnormality as the value increases.
The setting means sets a correction candidate amount of the initial value for each of the plurality of detection positions, sets a maximum value of the correction candidate amounts as the correction amount,
The setting means sets the correction candidate amount so that the downstream detection position of the plurality of detection positions has a larger value for the same skew level.
The feeding device according to claim 5. The setting means calculates a rotation amount of the sheet based on the detection results of the plurality of detection positions, and sets the correction amount based on the rotation amount;
The feeding device according to claim 5. The feeding means includes a pickup roller for taking out the sheets stacked on the sheet stacking means,
The deformation detection means includes
Among the fed sheets, a left area detecting means for detecting a deformation amount of a left area of the pickup roller when viewed in the sheet feeding direction;
A right region detecting means for detecting a deformation amount of a region on the right side of the pickup roller as viewed in the sheet feeding direction among the fed sheets,
The setting means sets the determination threshold for each of the left area and the right area,
The determination unit performs a determination of feeding abnormality based on a detection result of the left region detection unit and a determination of feeding abnormality based on a detection result of the right region detection unit, respectively.
The feeding device according to claim 3. The setting means includes
Based on the detection result of the skew detection means, the preceding region is specified out of the left region and the right region,
For the preceding area, the determination threshold is set by correcting the initial value based on the detection result of the skew detection means,
For an area that does not precede, the initial value is set as the determination threshold,
The feeding device according to claim 8. The deformation detection means includes
A light-emitting unit and a light-receiving unit that are spaced apart from each other in a direction intersecting the sheet feeding direction,
The light receiving unit includes a plurality of light receiving elements arranged in a stacking direction of sheets stacked on the sheet stacking unit,
The feeding device according to claim 1. The left area detection means and the right area detection means are respectively
Arranged away from the pickup roller in a direction intersecting the sheet feeding direction, and
A light emitting unit for irradiating light to the pickup roller;
A light receiving unit that receives reflected light from the pickup roller, and
The light receiving unit includes a plurality of light receiving elements arranged in a stacking direction of sheets stacked on the sheet stacking unit,
The feeding device according to claim 8. The skew detection means includes
Including a pair of sheet detecting means arranged to be separated from each other in a direction crossing the sheet feeding direction and detecting the sheet;
The feeding device according to claim 1. The feeding means is
A pickup roller for taking out the sheets stacked on the sheet stacking means;
A separation feeding unit that feeds the sheets taken out by the pickup roller one by one,
The skew detection means is located downstream of the feeding unit in the sheet feeding direction.
The feeding device according to claim 1. In the sheet feeding direction, the sheet detection unit is further disposed downstream of the skew detection unit, and further includes a sheet detection unit that detects the sheet,
The setting means sets the determination threshold to the initial value after the sheet is detected by the sheet detection means.
The feeding device according to claim 3. A method of controlling a feeding device,
The feeding device is
Sheet stacking means on which sheets are stacked;
A feeding means for feeding the sheets stacked on the sheet stacking means;
Deformation detection means for detecting deformation of the sheet fed by the feeding means;
Skew detection means for detecting skew of a sheet fed by the feeding means,
The control method is:
Obtaining each detection result of the deformation detection means and the skew detection means;
A step of determining whether there is a feeding abnormality based on each acquired detection result,
A control method characterized by that. A program for controlling a feeding device,
The feeding device is
Sheet stacking means on which sheets are stacked;
A feeding means for feeding the sheets stacked on the sheet stacking means;
Deformation detection means for detecting deformation of the sheet fed by the feeding means;
Skew detection means for detecting skew of a sheet fed by the feeding means,
The program is stored in a computer.
Obtaining each detection result of the deformation detection means and the skew detection means;
A step of determining whether or not there is a feeding abnormality based on each acquired detection result,
A program characterized by that.

Images