JP4895298B2 - Sheet feeding device - Google Patents

Description

  The present invention relates to a sheet feeding apparatus that feeds a sheet to an image forming apparatus such as a copying machine or a printer or an image reading apparatus such as a sheet feed scanner.

  2. Description of the Related Art Conventionally, a sheet feeding apparatus equipped in an image reading apparatus, an image forming apparatus, or the like feeds a sheet stacked on a stacking table to a conveyance path by a sheet feeding roller, and when the sheets are overlapped and fed out, a downstream feeding roller And a separation roller that is in pressure contact with the feeding roller separates the sheets one by one and feeds them to the conveyance path.

  The separation roller constantly receives a rotational force for pushing the sheet upstream, via a driving force transmission device such as a slip clutch. When the sheet is one sheet, the separation roller receives the sheet conveyance force and is fed to the feeding roller by the slip clutch. The follow-up rotation is allowed, but when a plurality of sheets are fed, the sheet is rotated in the direction in which the sheet is conveyed to the upstream side, and the sheets other than the uppermost sheet are pushed back to the upstream side.

  In such a conventional sheet feeding device, sheets are stacked one by one on the stacking table, but sheets that are bound in a bundle by stapler, clip, gluing, etc. are erroneously stacked on the stacking table. In this case, the sheets in the sheet bundle are separated and fed one by one. In such a case, the sheet bundle is rotated so that the uppermost sheet fed by the feeding roller is turned up around the stitched portion, becomes a wrinkle, is torn, or the entire sheet bundle is It may turn into a distorted shape.

  Further, an image reading apparatus provided with such a sheet feeding apparatus may not be able to reliably read a sheet image. Further, an image forming apparatus provided with such a sheet feeding device may not be able to reliably form an image on a sheet.

  Under these circumstances, conventionally, a light emitting unit that emits light and a light receiving unit that receives light emitted from the light emitting unit on both sides in the width direction of the sheet substantially orthogonal to the sheet feeding direction of the stacking table. Have been proposed (Patent Document 1).

In this proposal, an abnormal sheet feeding is detected by utilizing the fact that the sheet that has bounced up interrupts the optical path between the light emitting unit and the light receiving unit, thereby reducing the amount of light received by the light receiving unit. To prevent the sheet from being damaged or jammed.
JP 2004-182449 A

  However, in the above-mentioned Patent Document 1, since it is not possible to install anything that blocks light other than the sheet on the optical path between the light emitting unit and the light receiving unit of the stacking base, the upstream side of the sheet feeding roller in the sheet conveyance direction The light emitting part and the light receiving part are arranged in the. For this reason, the restriction plate that restricts the skew feeding of the sheets in contact with both sides in the width direction of the sheet bundle of the stacking base cannot be installed close to the sheet feeding position (loading position). The sheet feeding performance (take-in performance) is deteriorated due to insufficient sheet skew prevention effect.

  Therefore, the present invention is capable of detecting a sheet take-up abnormality with high accuracy, and is capable of arranging a restricting plate that restricts the skew feeding of the sheet close to the take-in position of the sheet, thereby taking up the sheet. An object of the present invention is to provide a sheet feeding apparatus capable of improving the above.

  In order to achieve the above object, a sheet feeding apparatus according to the present invention includes a take-in means having take-in rollers for taking in a conveyance path, and a sheet in contact with both sides in the width direction of the sheets stacked on the stacking unit. When a plurality of sheets that are disposed on the downstream side in the sheet conveyance direction of the take-in means and are taken into the conveyance path by the take-in rollers are overlapped, the sheet is 1 Separating and feeding means for separating and feeding the sheets one by one, an abnormality detecting means for detecting an abnormality in taking in the sheet into the conveyance path, and when the abnormality detecting means detects an abnormality in taking in the sheet, Control means for controlling at least one of the operation and the operation of the separation feeding means, and the abnormality detection means is disposed at substantially the same position as the take-in roller in the sheet conveyance direction. , Axial direction of the take-in roller A light emitting unit that emits light toward the vicinity of the side of the sheet, and a light receiving unit that is disposed at substantially the same position as the take-in roller in the sheet conveyance direction, and that receives the light emitted from the light emitting unit. And detecting an abnormality in taking in the sheet based on a change in the amount of light received by the light receiving unit when at least one of the light emitted from the light emitting unit and the light received by the light receiving unit is shielded by the sheet. And

  Further, the sheet feeding device of the present invention is disposed in the vicinity of the taking-in means, and guides the light irradiated by the light emitting part from the vicinity of one side part in the axial direction of the taking-in roller to the vicinity of the other side part. A light guide is further provided.

  According to the present invention, since the processing operation of the abnormality detection unit is not affected by the position of the restriction plate that restricts the skew feeding of the sheet, the restriction plate can be arranged close to the sheet take-in position. Accordingly, it is possible to detect an abnormality in taking in the sheet with high accuracy and to improve the taking-in performance of the sheet.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 is a schematic cross-sectional view for explaining an image reading apparatus including a document feeding apparatus (sheet feeding apparatus) according to a first embodiment of the present invention, and FIG. 2 is a schematic diagram of the image reading apparatus shown in FIG. It is a figure which shows a part typically.

  As shown in FIGS. 1 and 2, the image reading apparatus 200 of the present embodiment includes a document table (stacking unit) 1 on which a plurality of documents are stacked and driven up and down by a document table driving motor 2. On both sides of the document table 1 in the width direction of the document, there are provided restriction plates 51 that regulate the skew of the document in contact with both sides of the document bundle loaded on the document table 1 in the width direction. The document detection sensor 3 detects the document on the document table 1. A paper feed roller (take-in roller) 4 feeds a document on the document table 1 from the document table 1. The paper feed motor 5 rotates the paper feed roller 4.

  The feed roller 6 is rotationally driven by a feed motor 8 in a direction in which the document is conveyed downstream. The separation roller 7 always receives a rotational force for conveying the document upstream from the separation motor 9 via a slip clutch (not shown). However, when the number of documents is one, the separation roller 7 receives the document conveyance force and receives the document by the slip clutch. The feed roller 6 is allowed to follow and rotate and follow. Then, when there are a plurality of documents, the separation roller 7 rotates in a direction in which the document is conveyed upstream, and pushes the document back upstream.

  When the original is overlapped and fed into the nip between the feed roller 6 and the separation roller 7 by the action of feeding the original of the feed roller 6 downstream and the action of pushing the original of the separation roller 7 upstream. The upper document is conveyed downstream, the lower document is pushed back upstream, and the overlapping documents are separated and fed. A pair of separation belt rollers (not shown) may be used instead of the pair of rollers of the feeding roller 6 and the separation roller 7.

  The transport motor 10 drives a document transport roller for transporting the separated and fed document from the document reading position to the discharge position. The nip gap adjusting motor 11 adjusts the gap between the feeding roller 6 and the separation roller 7 or the pressure contact pressure of the feeding roller 6 against the separation roller 7 so that the document is fed with a gap suitable for the thickness of the document or the pressure contact pressure. Separate feed.

  The document reading unit 43 includes reading sensors 14 and 15 that read an image of the document, and changes the scanning interval based on the reading speed and resolution of the document. The document discharge sensor 16 detects that the document passes through the document reading unit 43 and is discharged to the document discharge unit 44.

  The registration rollers 17 and 18 temporarily stop to restrict the document from being conveyed downstream, and correct the skew of the document. The registration clutch 19 transmits the rotation of the conveyance motor 10 to the registration roller 18 or turns it off.

  The document transport rollers 20, 21, 22, and 23 transport the document F to the document discharge unit 44. The two guide plates of the upper guide plate 40 and the lower guide plate 41 guide the document F conveyed between the roller pairs 6 and 7, the registration rollers 17 and 18, and the document conveyance rollers 20, 21, 22 and 23. To do.

  Document sensors 30, 31, 32, and 33 are sensors that detect the document conveyed on the conveyance path, and the conveyance of the document is controlled based on the document detection timing by these sensors. Bounce detection sensors SS1 and SS2 detect a document that has jumped up on the document table 1.

  3 and 4 are diagrams showing the positional relationship between the flip-up detection sensors SS1 and SS2 and the original F. FIG.

  The bounce detection sensor SS1 is disposed on one side in the axial direction of the paper feed roller 4, and the bounce detection sensor SS2 is disposed on the other side in the axial direction of the paper feed roller 4. Both the spring-up detection sensors SS1 and SS2 are connected to the control unit 45.

  The splash detection sensor SS1 includes a light emitting unit SS1-a, a first light receiving unit SS1-b, and a second light receiving unit SS1-c. The splash detection sensor SS2 includes a light emitting unit SS2-a, a first light receiving unit SS2-b, and a second light receiving unit SS2-c.

  The light emitting sections SS 1-a and SS 2-a are composed of light emitting elements such as light emitting LEDs, and irradiate light toward the side portion in the axial direction of the paper feed roller 4.

  The first light receiving portions SS1-b and SS2-b are composed of light receiving elements such as light receiving sensors, and are irradiated from the light emitting portions SS1-a and SS2-a in the axial side surface or the paper feed roller. The light reflected in the vicinity of the side surface in the axial direction of 4 is received. In the present invention, the vicinity of the side portion in the axial direction of the take-in roller includes the side surface in the axial direction of the paper feed roller 4 and members disposed in the vicinity of the side surface of the paper feed roller 4.

  The second light receiving portions SS1-c and SS2-c are composed of light receiving elements such as a light receiving sensor, and are reflected by members in the axial side surface of the paper feed roller 4 or in the vicinity of the axial side surface of the paper feed roller 4. Receives reflected light (hereinafter referred to as abnormally reflected light) in an abnormally fed state of the document, which is generated by irregularly reflecting the irradiated light on the back surface of the document F when the reflected light is not received and when the document F jumps up. Arranged in position.

  The control unit (control unit) 45 controls the entire image reading apparatus 200 including the document feeding apparatus. For example, each roller is controlled by controlling each motor based on an output signal from each sensor. Rotate or stop.

  Next, the operation of the bounce detection sensor SS1 will be described. The bounce detection sensor SS2 is the same as the operation of the bounce detection sensor SS1, and therefore only the bounce detection sensor SS1 will be described.

  When the document F is being conveyed normally, the light irradiated from the light emitting unit SS1-a of the splash detection sensor SS1 is reflected by the side surface of the paper feed roller 4 and travels to the first light receiving unit SS1-b. The document F is not blocked.

  When the document F jumps up and blocks the optical path, as shown in FIG. 5, the amount of light received by the first light receiving unit SS1-b decreases and the document F becomes abnormal when the change amount ΔH exceeds the set value. Since it can be determined that the paper has been fed, it is possible to detect abnormal feeding of the document. In this case, the threshold of the received light amount may be provided as a reference value for determining that the document F has been abnormally fed, and abnormal feeding may be determined, or abnormal feeding may be determined by the rate of change in the received light amount. Also good. The control unit 45 controls the motor to stop the paper feed roller 4, the feed roller 6, and the separation roller 7 when the abnormal feed of the document is detected using the jump detection sensor SS <b> 1.

  By the way, when the document F jumps up, the optical path is interrupted and at the same time the back surface of the document F irregularly reflects the irradiated light to generate abnormally reflected light. As shown in FIG. 6, this abnormally reflected light is converted into the first light receiving unit SS1. -B may be received. In this case, the amount of light received by the first light receiving unit SS1-b cannot be determined as during normal conveyance, and the jumping of the document cannot be detected.

  Therefore, in the present embodiment, as described above, the second light receiving unit SS1-c is provided as an auxiliary sensor in addition to the first light receiving unit SS1-b. The second light receiving unit SS1-c is disposed at a position where the reflected light of the document F is received without receiving the reflected light when the document F is normally conveyed.

  As a result, as shown in FIG. 7, after the document F blocks the optical path and the amount of light received by the first light receiving unit SS1-b decreases, the amount of received light increases again due to abnormally reflected light, and the first light receiving unit SS1. Even when the abnormal paper feeding of the original cannot be detected using -b, the amount of light received by the second light receiving unit SS1-c is increased by the abnormal reflected light. When the change amount ΔH ′ exceeds the set value, it can be determined that the document F has been abnormally fed, and detection omission can be eliminated. The control unit 45 controls the motor to stop the paper feed roller 4, the feed roller 6, and the separation roller 7 when the abnormal light feeding of the original is detected using the second light receiving unit SS 1-c. .

  In addition, a reflection part (not shown) such as a mirror is provided in the vicinity of the side surface in the axial direction of the paper feed roller 4 so that the irradiation light from the light emitting part SS1-a is more reliably reflected to the second light receiving part SS1-b. You may do it. In this case, the smaller the area of the reflection part, the narrower the optical path between the light emitting part SS1-a and the reflection part. The narrower the optical path, the shorter the time required for the jumped document to block the optical path, so that the jump of the document can be detected quickly.

  As described above, in the present embodiment, it is possible to detect an abnormal document feeding with high accuracy using the jump detection sensors SS1 and SS2.

  Further, the bounce detection sensor SS1 is arranged on one side in the axial direction of the paper feed roller 4, and the bounce detection sensor SS2 is arranged on the other side in the axial direction of the paper feed roller 4. That is, the jump detection sensors SS1 and SS2 can be arranged at substantially the same position as the paper feed roller 4 with respect to the document transport direction to detect abnormal paper feed. , SS2 can be disposed closer to the document feed position than when the document feed roller 4 is disposed upstream of the document transport direction.

  As a result, the document regulating plate 51 can maximize the effect of preventing the skew of the document and improve the document feeding performance.

  Furthermore, when the light emitted from the light emitting portions SS1-a and SS2-a of the splash detection sensors SS1 and SS2 is diffusely reflected on the back surface of the raised document and received by the first light receiving portions SS1-b and SS2-b. In addition, since the jumping of the document can be detected by increasing the amount of light received by the second light receiving units SS1-c and SS2-c, it is possible to detect the abnormal paper feed with high accuracy and no detection omission. Can do.

  Instead of using the reflection of the paper feed roller or the like, the light guide from the light emitting units SS1-a and SS2-a is guided near the paper feed roller 4 or a member supporting the paper feed roller 4. An optical part may be provided. In this case, the second light receiving parts SS1-c and SS2-c that receive light when the light emitted from the light emitting parts SS1-a and SS2-a is reflected from the back side of the document are located in the vicinity of the light emitting parts SS1-a and SS2-a. The first light receiving portions SS1-b and SS2-b that receive the light irradiated by the light emitting portions SS1-a and SS2-a and passed through the light guide portion are referred to as the light emitting portions SS1-a and SS2-a. It is provided on the opposite side, and when the first light receiving portions SS1-b and SS2-b do not receive light and the second light receiving portions SS1-c and SS2-c receive light, it is determined that the document is abnormally fed. Therefore, it is possible to detect abnormal paper feed with high accuracy.

(Second Embodiment)
Next, with reference to FIGS. 8 to 14, a document feeder according to a second embodiment of the present invention will be described. In addition, about the part which overlaps or corresponds to the said 1st Embodiment, the same code | symbol is attached | subjected to a figure and the description is abbreviate | omitted.

  As shown in FIGS. 8 and 9, the document feeding apparatus 102 according to the present embodiment includes a bounce detection sensor SS <b> 3 arranged on one side in the axial direction of the paper feed roller 4, and the bounce detection sensor SS <b> 4 serves as the paper feed roller 4. Is disposed on the other side in the axial direction. Both the spring-up detection sensors SS3 and SS4 are connected to the control unit 45.

  The splash detection sensors SS3 and SS4 are both light emitting units SS3- each composed of a plurality of N light emitting elements arranged one-dimensionally in a direction perpendicular to the document stacking surface (sheet stacking surface) 1a of the document table 1. a, SS4-a, first light receiving portions SS3-b, SS4-b made of one light receiving element, and second light receiving portions SS3-c, SS4-c made of one light receiving element.

  The bounce detection sensors SS3 and SS4 sequentially turn on 1 to N light emitting elements of the light emitting sections SS3-a and SS4-a during document feeding. When the first light receiving units SS3-b and SS4-b receive light, the light emission timings of the plurality of light emitting elements of the light emitting units SS3-a and SS4-a and the first light receiving unit SS3 for each timing. Since the light path of the light emitting element is blocked by the presence / absence of light reception of -b and SS4-b, the amount of jumping up of the document can be detected in multiple values.

  Next, the operation of the bounce detection sensor SS3 will be described. The bounce detection sensor SS4 is the same as the operation of the bounce detection sensor SS3, so only the bounce detection sensor SS3 will be described.

  A user places a plurality of documents F on the document table 1. A start signal is sent from the operation unit 46 (see FIG. 1) such as a panel to the control unit 45 by a user operation. The operation unit 46 also has a display function. When it is detected that the amount of jumping or curling of the document is large, the control unit 45 can display the abnormal paper supply state on the operation unit 46 to inform the user. When a start signal from the operation unit 46 is sent to the control unit 45, the control unit 45 sends an ascending signal to the document table drive motor 2 to raise the document table 1 to the document feeding position.

  At this time, the amount of jump when the document is loaded is stored as an offset level in a storage area (not shown) in the control unit 45.

  FIG. 10 is a graph showing the amount of jumping detected from the output signal of the first light receiving unit SS3-b when a normal document without curl is conveyed without any problem. The Δ offset value in the figure means that the light blocking state of each optical path of a plurality of sensors changes according to the twist, wrinkle, distortion, etc. of the document being fed.

  FIG. 11 shows the amount of jump detected from the output signal of the first light receiving unit SS3-b when a curled document is conveyed without any problem. The offset level is larger than that in FIG. Since the change in the offset value is small and the sheet feed stop level has not been reached, it can be seen that there is no problem with document feeding.

  Thereby, the control unit 45 stores the initial curl amount (offset level) of the original when the original table 1 is raised to the predetermined original feed start position even for the curled original. The operation can be continued by making a determination using the difference (Δ offset value) from the amount of jumping detected from the output signal of the first light receiving unit SS3-b during paper feeding.

  That is, when the initial curl amount of the document exceeds the curl amount that causes the jam, the control unit 45 does not feed the document and reports the abnormal feeding state to the user through the operation unit 46. If the initial curl amount of the original does not exceed the amount of curl that causes jamming, the control unit 45 feeds the original.

  In addition, as shown in FIG. 12, when the curled document is bound in a bundle by a binding member SP1 such as a staple, a clip, or a glue, the curled document is fed by the paper feed roller 4 and the jump detection sensor SS3 When passing forward, the document is brought into a state as shown in FIG. 13 by the document feeding operation.

  As shown in FIG. 14, the amount of jump detected from the output signal of the first light receiving unit SS3-b at this time is such that the difference (Δ offset value) between the initial curl amount and the amount of jump increases to the plus side. It will follow. In this case, when the difference becomes equal to or higher than the paper feed stop level, the control unit 45 stops the paper feed. Also, when the document curl amount alone exceeds a separately set limit value, that is, when the initial curl amount and the increased curl amount are added, and the curl amount exceeds the amount of curl. In addition, the control unit 45 stops feeding the document and informs the user that the document is abnormally fed through the operation unit 46.

  Conversely, as the curl amount of the document decreases, the difference may decrease to a negative value. In this case, since the curl amount of the document decreases, the control unit 45 continues to feed the document.

  Note that the bounce detection sensors SS3 and SS4 in the document feeder 102 of the present embodiment include a plurality of light emitting units and a first light source arranged one-dimensionally in a direction perpendicular to the document stacking surface 1a of the document table 1. However, the number of light-receiving units that receive light from the light-emitting unit when feeding a document, or the light-receiving unit is configured to have one light-emitting unit and a plurality of first light-receiving units. The amount of jumping of the document may be detected in a multivalued manner by using the change in the amount of received light. Of course, you may make it arrange | position the splash detection sensors SS3 and SS4 which have a some light emission part and a some light-receiving part.

  Also in this embodiment, it is possible to carry out a modification in which a light guide portion is provided in the vicinity of the paper feed roller or its supporting member instead of using the reflection of the paper feed roller or the like, and the same effect can be obtained. It is done. Details will be described in a fourth embodiment.

  Further, the second light receiving portions SS3-c and SS4-c that receive the abnormally reflected light irregularly reflected on the back surface of the jumped document are auxiliary sensors that further increase the certainty of detection, and the second light receiving portion SS3. The operation of determining that the document F has been abnormally fed when the amount of received light of −c increases and the amount of change exceeds the set value, and other configurations and effects are the same as in the first embodiment. Therefore, the description thereof is omitted.

(Third embodiment)
Next, with reference to FIG. 15 and FIG. 16, the document feeder which is the 3rd Embodiment of this invention is demonstrated. In addition, about the part which overlaps or corresponds to the said 1st Embodiment, the same code | symbol is attached | subjected to a figure and the description is abbreviate | omitted.

  As shown in FIGS. 15 and 16, the document feeder 103 according to the present embodiment includes a bounce detection sensor SS <b> 5, and the bounce detection sensor SS <b> 5 is arranged on one side in the axial direction of the paper feed roller 4. A light emitting unit SS5-a made up of a light emitting LED and a light receiving unit made up of a light receiving element such as a light receiving sensor arranged on the other side in the axial direction of the paper feed roller 4 and receiving light emitted from the light emitting unit SS5-a SS5-b. Further, in the vicinity of the paper feed roller 4, a light guide unit 60 that guides the light emitted from the light emitting unit SS5-a to the light receiving unit SS5-b is provided.

  The light guide unit 60 is composed of a light guide or the like, and emits light emitted from the light emitting unit SS5-a to one side portion in the axial direction of the paper feed roller 4 in the axial direction of the paper feed roller 4 from the one side portion. The light is guided to the other side and guided to the light receiving unit SS5-b. When the jumped document blocks the light path from the light emitting unit SS5-a to the light receiving unit SS5-b, it is determined that the document has jumped up, and abnormal document feeding is detected. Thereby, it is possible to detect abnormal document feeding on both sides of the sheet feeding roller 4 in the axial direction. The control unit 45 controls the motor to stop the paper feed roller 4, the feed roller 6, and the separation roller 7 when the document is detected to be abnormally fed using the splash detection sensor SS 5.

  In the present embodiment, even if there is an obstacle such as the paper feed roller 4 on the optical path that linearly connects the light emitting unit SS5-a and the light receiving unit SS5-b, the light emitting unit is provided by arranging the light guide unit 60. An optical path connecting SS5-a and the light receiving unit SS5-b can be secured to detect an abnormal paper feed.

  Obstacles are not limited to the paper feed roller, and even if there are multiple other obstacles, an optical path necessary for detecting abnormal paper feed by forming a light guide according to the shape of the obstacle. Can be secured. Other configurations and operational effects are the same as those of the first embodiment.

(Fourth embodiment)
Next, with reference to FIG. 17 and FIG. 18, a document feeder which is a fourth embodiment of the present invention will be described. Portions that overlap or correspond to those in the first embodiment are given the same reference numerals in the drawings, and descriptions thereof are omitted.

  As shown in FIGS. 17 and 18, the document feeder 104 of the present embodiment is provided with jump detection sensors SS <b> 6 and SS <b> 7 on both sides in the axial direction of the paper feed roller 4.

  The splash detection sensors SS6 and SS7 are composed of N light emitting elements arranged one-dimensionally in a direction perpendicular to the document stacking surface (sheet stacking surface) 1a of the document table 1, and are arranged in the axial direction of the paper feed roller 4. Light emitting units SS6-a and SS7-a that irradiate light on the side portions, and light receiving units SS6-b and SS7-b that receive light emitted from the light emitting units SS6-a and SS7-a are provided. In addition, a light guide unit 60 is provided in the vicinity of the paper feed roller 4.

  The light guide 60 is composed of a light guide or the like, and the light emitted from the light emitting part SS6-a is applied to the light receiving part SS6-b, and the light emitted from the light emitting part SS7-a is applied to the light receiving part SS7-b. Each is supposed to lead.

  The light emitting unit SS 6-a is disposed on one side in the axial direction of the paper feed roller 4, and the light receiving unit SS 6-b is disposed on the other side in the axial direction of the paper feed roller 4. The light emitting unit SS7-a is disposed on the light receiving unit SS6b side, and the light receiving unit SS7-b is disposed on the light emitting unit SS6-a side. By using the spring-up detection sensors SS6 and SS7, it is possible to detect abnormal document feeding on both sides of the sheet feeding roller 4 in the axial direction. The operations of the bounce detection sensors SS6 and SS7 are the same as those of the bounce detection sensors SS3 and SS4 in the second embodiment, and a description thereof will be omitted.

  In the present embodiment, similarly to the third embodiment, even if there is an obstacle on the optical path that linearly connects the light emitting units SS6-a and SS7-a and the light receiving units SS6-b and SS7-b, By arranging the light guide unit 60, it is possible to secure an optical path between the light emitting units SS6-a and SS7-a and the light receiving units SS6-b and SS7-b, and to detect abnormal paper feeding of the document. . Other configurations and operational effects are the same as those of the first and second embodiments.

  In the first to fourth embodiments, the light emitting unit and the light receiving unit of the splash detection sensors SS1 to SS7 are often attached to the main body side of the image reading device, but these attachment parts are not particularly limited, You may make it attach to the control board 51. FIG.

  In this way, the distances from the light emitting unit and the light receiving unit to the document can always be kept constant. Therefore, when multivalue detection is performed as in the second and fourth embodiments, the interval between the multivalued optical paths is set. Since detection can be performed at a position that does not become narrow, the detection width in the vertical direction is always constant and a wide range of detection can be performed.

(Fifth embodiment)
Next, a document feeder according to a fifth embodiment of the present invention will be described with reference to FIGS. In the present embodiment, the document feeder 104 according to the fourth embodiment is different only in that a flat light guide unit 61 is provided instead of the light guide unit 60. Only the differences will be described.

  As shown in FIGS. 19 and 20, the document feeder 105 of the present embodiment has a length in the vertical direction with respect to the document stacking surface 1 a of the document table 1 of the flat plate-shaped light guide unit 61. It is substantially equal to the length of the vertical installation area of SS7-a. The light emitted from each light emitting element of the light emitting sections SS6-a and SS7-a is substantially parallel to the document stacking surface 1a of the document table 1 as shown in FIG. The light is guided so as to pass through. Therefore, the detection width in the vertical direction is constant at any position on the optical path, and a wide range of document jump detection can be detected.

  In the fourth embodiment, as shown in FIG. 18, the distance between the optical paths of the light emitting elements becomes narrower as it approaches the light guide unit 60, so the detection width in the vertical direction becomes narrower for a document with a narrow paper width. However, by using the flat light guide 61, the detection width can be widened even at a portion close to the light guide 61, so that the detection of abnormal paper feed can be quickly started from the stage where the amount of document jumping is small.

  On the other hand, the flat light guide 61 has a larger area of light incident than the light guide 60 of the fourth embodiment. Therefore, as shown in FIG. 21B, the light emitted from each light emitting element and passing through the light guide unit 61 is reflected by the lower surface and the upper surface of the light guide unit 61 and the directivity is disturbed. For this reason, since the time required for the sheet that has bounced up to completely block the optical path to be long, the detection speed of the document bounce is slowed down. In addition, there is a high possibility that external light or the like unnecessary for detecting the jumping of the document will be incident. As a result, even if the bounced document blocks the optical path, detection failure occurs due to external light being guided and received by the light receiving unit, and there is a high possibility that the detection accuracy will decrease.

  Therefore, in the present embodiment, the light path disturbing the directivity, that is, the light incident on the flat light guide 61, as shown in FIG. A countermeasure (described later) is taken so as not to form a reflected optical path that is reflected by 61-b and emitted from the light guide section 61. Accordingly, only substantially parallel light is guided to the light receiving unit, and the directivity of each light emitting element can be sharpened, so that the detection speed can be prevented from decreasing. Moreover, since the external light guided to the light receiving portion can be reduced, it is possible to prevent a decrease in detection accuracy.

  As a countermeasure method for preventing the reflected light from being generated at the upper part 61-a and the lower part 61-b of the light guide part 61, as shown in FIG. 22 (a), the upper part 61-a and the lower part 61-b of the light guide part 61. Is colored black or the like. As a result, the light that has entered the light guide portion 61 and hits the upper portion 61-a and the lower portion 61-b is absorbed by the colored portion, and the reflected light from the upper portion 61-a and the lower portion 61-b of the light guide portion 61 is reflected. Can be eliminated. In this case, the upper part 61-a and the lower part 61-b of the light guide part 61 may be formed of a resin containing a pigment.

  Further, as another countermeasure, as shown in FIG. 22B, the entire upper portion 61-a and the lower portion 61-b of the light guide 61 are inclined, that is, on the document stacking surface 1a of the document table 1. There is a way to make the surface angled. Thereby, when the light incident on the light guide part 61 hits the upper part 61-a and the lower part 61-b, it is reflected in a direction not toward the light receiving part, so that the light can be diffused to the outside, and the upper part 61 -A and the light reflected by the lower part 61-b can be prevented from being received by the light receiving unit.

  Furthermore, as another countermeasure, as shown in FIG. 23, there is a method of providing concave shapes, that is, notches 61-c and 61-d, in the upper part 61-a and the lower part 61-b of the light guide part 61, respectively. The shape of the notch is formed so that all the light that reaches the light receiving part will be reflected when there is no notch, so that the light hitting the notch is reflected toward the incident side It has become.

  Thereby, the reflected light which is reflected by the upper part 61-a and the lower part 61-b of the light guide part 61 and reaches the light receiving part can be eliminated. However, part of the light that hits the notch may be transmitted without being reflected, so that the light that has exited the light guide unit 61 is incident again and guided, and the detection accuracy decreases. there is a possibility. In order to prevent this, the cut surface of the notch is colored with black or the like to absorb light. In this way, a decrease in detection accuracy can be prevented.

  FIG. 24 is a schematic top view showing the positional relationship among the splash detection sensors SS6 and SS7, the paper feed roller 4, and the flat light guide 61. In order to place the document regulating plate 51 close to the paper feed roller 4, the bounce detection sensors SS6 and SS7 are light guides in which the line connecting the light emitting part and the light receiving part is substantially parallel to the axis of the paper feed roller 4. It is arranged so as to pass through the downstream side in the document transport direction from the section 61 so that the optical path avoids the document regulating plate 51.

  For this reason, after the light irradiated from light emission part SS6-a and SS7-a injects into the light guide part 61, it reflects with the front surface 61-e and the rear surface 61-f, and is light-guided. Since the area of the front surface and the rear surface of the light guide unit 61 is larger than the light guide unit 60 of the fourth embodiment, external light unnecessary for detection may be incident from the front surface 61-e and the rear surface 61-f. Get higher. In this case, even if the bounced document blocks the optical path, detection failure occurs due to external light being guided and received by the light receiving unit, and there is a high possibility that the detection accuracy is lowered.

  As a countermeasure, there is a method of absorbing external light by covering the front surface 61-e and the rear surface 61-f of the light guide unit 61 with a member colored in black or the like. Since this method can prevent the incidence of external light, it can prevent a decrease in detection accuracy. Other configurations and operational effects are the same as those of the first and fourth embodiments.

  In addition, this invention is not limited to what was illustrated by said each embodiment, In the range which does not deviate from the summary of this invention, it can change suitably.

  For example, in each of the above-described embodiments, when the abnormal paper feeding of the document is detected, the control unit 45 controls to stop both the paper feed roller 4 and the roller pairs 6 and 7, but if at least one of them is stopped, This may be done if sufficient, or one or both may be controlled to rotate backwards.

  In each of the above embodiments, the case where the present invention is applied to the document feeder is illustrated. However, a recording material on which an image is not formed instead of the document is fed to the image forming unit of the image forming apparatus. The present invention may be applied to a recording material feeding apparatus.

  Further, in each of the above-described embodiments, the case where the present invention is applied to the document feeding device mounted on the image reading device has been exemplified. However, the document mounted on the document post-processing device that binds the document or opens a hole. The present invention may be applied to a feeding device.

1 is a schematic cross-sectional view for explaining an image reading apparatus including a document feeding device according to a first embodiment of the present invention. It is a figure which shows typically the principal part of the image reading apparatus shown in FIG. 1 is a schematic side view of a document feeding device according to a first embodiment of the present invention. FIG. 4 is a perspective view illustrating a main portion of the document feeding device illustrated in FIG. 3. It is a graph which shows the example of an output of the 1st light-receiving part of a bounce detection sensor. FIG. 6 is a perspective view of a state in which a document in which a corner of a leading end is bound by a staple is bounced up. It is a graph which shows the example of an output of the 1st light-receiving part of a bounce detection sensor, and a 2nd light-receiving part. FIG. 6 is a schematic side view of a document feeder that is a second embodiment of the present invention. FIG. 9 is a perspective view for explaining a main part of the document feeder shown in FIG. 8. It is a graph which shows the example of an output of a bounce detection sensor. FIG. 10 is a graph showing an example of output from a bounce detection sensor in the case of a document with a large curl amount. FIG. 6 is a perspective view showing a state in which both sides of a document in which the center of the leading end is bound by stapling are flipped up. FIG. 6 is a perspective view of a state in which both sides of a document in which the center of the leading end is bound by a staple are jumped up to an amount that causes a jam. FIG. 6 is a graph showing an output example of a bounce detection sensor when the leading edge of a document is bound. FIG. 6 is a schematic side view of a document feeder that is a third embodiment of the present invention. FIG. 16 is a perspective view for explaining a main part of the document feeder shown in FIG. 15. It is a schematic side view of the document feeder which is the 4th Embodiment of this invention. FIG. 18 is a perspective view for explaining a main part of the document feeder shown in FIG. 17. It is a schematic side view of the document feeder which is the 5th Embodiment of this invention. It is a perspective view for demonstrating the principal part of the original document feeding apparatus shown in FIG. It is explanatory drawing for demonstrating a flat type light guide part. It is explanatory drawing for demonstrating a flat type light guide part. It is explanatory drawing for demonstrating a flat type light guide part. It is a schematic top view which shows a positional relationship.

Explanation of symbols

S1 sensor before feeding document S2 sensor after feeding document S3 sensor before registration S4 sensor after registration SS1 Bounce detection sensor (abnormality detection means)
SS2 Bounce detection sensor (abnormality detection means)
SS3 Bounce detection sensor (abnormality detection means)
SS4 Bounce detection sensor (abnormality detection means)
SS5 Bounce detection sensor (abnormality detection means)
SS6 Bounce detection sensor (abnormality detection means)
SS7 Bounce detection sensor (abnormality detection means)
F Original (sheet)
1 Document table (loading section)
1a Document stacking surface (sheet stacking surface)
2 Document drive motor 3 Document detection sensor 4 Paper feed roller (take-in roller, take-in means)
5 Paper feed motor (take-in means)
6 Feeding roller (separate feeding means)
7 Separation roller (separation feeding means)
8 Feed motor (separate feed means)
9 Separation motor (separation feeding means)
DESCRIPTION OF SYMBOLS 10 Conveyance motor 11 Nip gap adjustment motors 14 and 15 Reading sensor 16 Original discharge sensors 17 and 18 Registration roller 19 Registration clutch 20, 21 Conveyance rollers 22 and 23 Conveyance roller 32 Pre-registration sensor 33 Post-registration sensor 43 Original reading unit 45 Control unit (Control means, abnormality detection means)
46 Operation Unit 51 Document Restriction Plate 60 Light Guide Unit 61 Flat Plate Light Guide Unit 101 Document Feeder (Sheet Feeder)
102 Document feeder (sheet feeder)
103 Document feeder (sheet feeder)
104 Document feeder (sheet feeder)
105 Document feeder (sheet feeder)
200 Image reader

Claims (9)

Take-in means having take-in rollers for taking the sheet placed on the stacking unit into the conveyance path;
A regulation plate that regulates the skew of the sheet in contact with both sides in the width direction of the sheet stacked on the stacking unit;
Separation feeding that is arranged downstream of the take-in means in the sheet conveyance direction and separates and feeds the sheets one by one when a plurality of sheets taken into the conveyance path by the take-in rollers overlap. Sending means,
An abnormality detecting means for detecting an abnormality in taking the sheet into the conveyance path;
Control means for controlling to change at least one of the operation of the take-in means and the operation of the separation feeding means when the abnormality detection means detects a sheet take-in abnormality,
The abnormality detection means is disposed at substantially the same position as the take-in roller in the sheet conveyance direction, and emits light toward the vicinity of the side portion in the axial direction of the take-in roller, and the sheet conveyance A light receiving portion that is disposed at substantially the same position as the take-in roller with respect to the direction and receives light emitted from the light emitting portion;
An abnormality in taking in the sheet is detected based on a change in the amount of light received by the light receiving unit when at least one of the light emitted from the light emitting unit and the light received by the light receiving unit is shielded by the sheet. Sheet feeding device. A light guide portion disposed in the vicinity of the sheet taking-in means and guiding the light emitted from the light emitting portion from the vicinity of one side in the axial direction of the take-in roller to the vicinity of the other side;
The sheet feeding apparatus according to claim 1. The light emitting unit includes a plurality of light emitting elements arranged in a substantially vertical direction with respect to a sheet stacking surface of the stacking unit.
The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus is a sheet feeding apparatus. The light receiving unit includes a plurality of light receiving elements arranged in a substantially vertical direction with respect to a sheet stacking surface of the stacking unit.
The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus is a sheet feeding apparatus. The length of the light guide unit in the vertical direction with respect to the sheet stacking surface of the stacking unit is substantially equal to the longer of the vertical length of the light emitting unit and the vertical length of the light receiving unit. That's it,
The sheet feeding apparatus according to claim 3, wherein the sheet feeding apparatus is a sheet feeding apparatus. At least one of an upper part and a lower part in the vertical direction with respect to the sheet stacking surface of the stacking unit of the light guide unit is a colored unit,
Of the light incident on the light guide part, the light passing through the colored part is absorbed.
The sheet feeding apparatus according to claim 5, wherein the sheet feeding apparatus is a sheet feeding apparatus. Providing a slope-shaped portion on at least one of an upper part and a lower part in a direction perpendicular to a sheet stacking surface of the stacking unit of the light guide unit;
Of the light incident on the light guide part, the light that hits the slope-shaped part is reflected in a direction not received by the light receiving part,
The sheet feeding apparatus according to claim 5, wherein the sheet feeding apparatus is a sheet feeding apparatus. A recess is provided in at least one of an upper part and a lower part in a direction perpendicular to the sheet stacking surface of the stacking unit of the light guide unit;
Of the light incident on the light guide part, the light hitting the concave part is reflected in a direction not received by the light receiving part,
The sheet feeding apparatus according to claim 5, wherein the sheet feeding apparatus is a sheet feeding apparatus. The abnormality detection unit includes another light receiving unit that receives light reflected by the sheet irradiated by the light emitting unit when the sheet of the stacking unit has an abnormal shape,
Detecting an abnormal loading of the sheet according to an increase in the amount of light received by the other light receiving unit;
The sheet feeding apparatus according to claim 1, wherein the sheet feeding apparatus is a sheet feeding apparatus.

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