JP2006256777A - Paper feeding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily and certainly set a document, to restrain cost increase of a device and to realize miniaturization of the device. <P>SOLUTION: This paper feeding device is furnished with a driving transmission mechanism 63 having a paper feeding tray 22 free to load a plurality of sheets of document, an inlet chute part 29 to guide the document to a carrier passage 26, an inlet roller 34, an inlet nipping piece 35, a separation roller 36 and a separation nipping piece 37 arranged on the inlet chute part 29 and a one-round clutch 65 to allow idling of the inlet roller 34 in a predetermined range and to transmit rotation of the separation roller 36 to the inlet roller 34, an ADF cover 28 arranged free to open and close against an ADF main body 27 and a returning means to rotate the inlet roller 34 to an end in the paper feeding opposite direction in an idling range allowed by the one round clutch 65 in accordance with closedown motion to change the ADF cover 28 in an open posture to a closed posture. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a paper feeding device that separates a document placed on a paper feeding tray and feeds it to a conveyance path.

  Conventionally, a copier, a scanner, a printer, a multi-function device having these functions, and the like are equipped with an ADF (Auto Document Feeder) that transports a document from a paper feed tray to a paper discharge tray through a transport path. ing. In such an ADF, a paper feeding device is provided as a mechanism that separates a plurality of documents and recording papers placed on a paper feeding tray and sequentially feeds them sequentially to a conveyance path.

  For example, in a paper feeding device 91 provided in a conventional ADF 90 as shown in FIG. 20, a suction chute portion 93 is formed continuously with a paper feeding tray 92 for placing a document. A suction roller 94, a suction nip piece 95, a separation roller 96, and a separation nip piece 97 are provided.

  The suction roller 94 is rotatably disposed on the lower guide surface of the suction chute 93. A suction nip piece 95 is disposed on the upper guide surface of the suction chute 93 that is opposed to the suction roller 94 so as to be able to contact and separate from the suction roller 94 and is biased by a spring material (not shown). The suction roller 94 is in pressure contact. The document set on the sheet feed tray 92 is urged toward the suction roller 94 by the suction nip piece 95, and the lowermost document in pressure contact with the suction roller 94 receives the rotation of the suction roller 94 in the sheet feeding direction. Sent out.

  The separation roller 96 is rotatably disposed on the lower guide surface of the suction chute 93, spaced from the suction roller 94 in the paper feeding direction. A separation nip piece 97 is disposed on the guide surface on the upper side of the suction chute 93 that is opposed to the separation roller 96 so as to come into contact with and separate from the separation roller 96 and is urged by a spring material (not shown). It is in pressure contact with the separation roller 96. The document sent out by the suction roller 94 is nipped by the separation roller 96 and the separation nip piece 97, and is further sent out in the paper feeding direction under the rotation of the separation roller 96.

  A laterally substantially U-shaped conveyance path 98 is formed on the downstream side from the suction chute 93 and is fed from the paper feed tray 92 by the conveyance roller 99 and the pinch roller 100 disposed in the conveyance path 98. The original document is conveyed along the conveyance path 98. During the conveyance process, the document is guided by the guide member 101 and conveyed onto the platen glass 102, and an image of the document passing over the platen glass 102 is read by the image scanner 103 disposed below the platen glass 102. It is done. The read original is discharged from the conveyance path 98 to the paper discharge tray 104.

  As described above, in order to feed the document in the paper feeding direction by the rotation of the suction roller 94, when the document is set on the paper feed tray 92, the leading edge of the document comes from the nip position between the suction roller 94 and the suction nip piece 95. It needs to be inserted to the back side. At this time, if the suction roller 94 and the suction nip piece 95 are in pressure contact with each other, the user presses the document into the nip position so that the suction nip piece 95 is retracted, and further, the document in the nip state is The front and back surfaces are pushed in such a manner as to slide with respect to the suction roller 94 and the suction nip piece 95.

  However, if a feeling of resistance occurs in the insertion of the document at the nip position between the suction roller 94 and the suction nip piece 95, the user may mistake the position as the insertion limit position and end the document insertion. In this case, the document setting is not completed, and the document cannot be fed by the suction roller 94. When the number of documents is small, the bundle of documents is not stiff, and the document may be bent at the nip position between the suction roller 94 and the suction nip piece 95.

  In order to avoid such a problem, when setting the document, it is possible to retract either the suction roller 94 or the suction nip piece 95 and provide a gap for inserting the document therebetween. Conventionally, it is made (for example, refer patent document 1). For example, as shown in the figure, there is a means for providing the suction roller 94 so as to be able to protrude and retract with respect to the guide surface of the suction chute 93 and operating the suction roller 94 by a solenoid (not shown). According to this, when the paper feeding device 91 is not operated, the suction roller 94 is retracted, so that a gap is formed between the suction nip piece 95 and the document can be easily inserted and removed. When paper is fed after the document is set, the suction roller 94 is protruded and the document is nipped between the suction nip piece 95. Then, when the suction roller 94 is rotated, the lowermost document is sent out in the paper feeding direction.

JP 2000-296927 A

  However, in order to make the suction roller 94 appear and disappear, a space for retracting the suction roller 94 is provided in the suction chute portion 93. Further, a space for arranging a solenoid for moving the suction roller 94 in and out is required, which is not preferable for downsizing the apparatus. Further, when the number of parts such as solenoids increases, there is a problem that the cost increases, and when the number of parts increases, the assembly work of the apparatus becomes complicated.

  The present invention has been made in view of such a problem, and an object of the present invention is to provide means for easily and surely setting a document, suppressing an increase in cost of the apparatus, and realizing downsizing of the apparatus. To do.

  A paper feed device according to the present invention has a paper feed tray on which a plurality of papers to be fed can be stacked, and a guide surface facing a predetermined width, and guides the paper from the paper feed tray to a conveyance path. A part of the roller surface of the suction chute and a guide surface of the suction chute exposed so as to contact the paper loaded on the paper feed tray and transfer the paper to the transport path. A first roller that feeds in and a first guide surface of the suction chute that protrudes so as to be able to come into contact with and separate from the first roller and elastically biased so as to contact the first roller. A contact member and one guide surface of the suction chute are disposed at a position separated from the first roller in the paper feeding direction with a part of the roller surface exposed. A second roller for feeding the paper fed by the roller further in the paper feeding direction; A second abutting member projecting on the other guide surface of the seat portion so as to be able to come into contact with and away from the second roller and elastically biased so as to abut against the second roller; And a drive transmission mechanism having a clutch that allows the first roller to idle in a predetermined range and transmits the rotation of the second roller to the first roller. One of the opposing guide surfaces of the suction chute and is arranged to be openable and closable with respect to the apparatus main body. The first and second rollers and the first contact The first roller based on a cover member that opens the suction chute so that the member and the second contact member are separated from each other, and a closing operation that changes the cover member in the open posture to the closed posture. The reverse of the idling range allowed by the clutch And return means for rotating the end, is made of comprises a.

  The user places the paper to be fed on the paper feed tray with the leading end inserted into the suction chute. The leading edge of the paper abuts on the first roller, but the first roller can idle in a predetermined range and is positioned at the end of the idling range in the paper feed reverse direction, so the user almost feels resistance. Without this, the first roller can be idled in the paper feeding forward direction to insert the paper further into the back. Further, the leading edge of the paper also comes into contact with the first contact member, but since the first contact member can be retracted toward the guide surface side, the user retracts the first contact member to the paper. Can be inserted further into the back. The leading edge of the paper inserted further into the back from the position where the first roller and the first contact member are disposed contacts the second roller. Since the load of the driving mechanism is applied to the second roller, the user who inserts the sheet feels resistance, and the user recognizes the position as the insertion limit position. When the inserted paper is placed on the paper feed tray, the paper setting is completed.

  The leading edge of the paper placed on the paper feed tray is inserted deeper than the position where the first roller and the first contact member are disposed, and the paper is pushed by the first contact member. Thus, one surface of the paper is in contact with the first roller. In this state, when the first roller and the second roller are rotated by the drive mechanism and the drive transmission mechanism, the sheet in contact with the first roller is sent out in the paper feeding direction, and the second roller Nipped with the second abutting member, and further fed into the conveyance path.

  Further, as described above, when the paper is set in the paper feed tray, the first roller is idled in the paper feed forward direction from the paper feed reverse direction end of the idling range, and from that position in the paper feed reverse direction. It is possible to idle. Therefore, when the user pulls out the paper from the suction chute after setting the paper in the paper feed tray, the first roller idles in the reverse direction of the paper feed as the paper is pulled out. Paper can be pulled out with almost no resistance.

  Further, even when the user opens the cover member to clear the paper jam and touches the first roller to make it idle, the return means is configured to return the first member based on the closing operation of the cover member. The roller is returned to the end in the reverse feed direction of the idling range permitted by the clutch. Therefore, after closing the cover member, the paper can be set in the paper feed tray in the same manner as described above.

  Further, the present invention is the motion transmission mechanism in the paper feeding device, wherein the return means transmits the rotational motion in the closing operation of the cover member as the rotational motion of the first roller. Thereby, the return means can be realized mechanically.

  According to the present invention, in the sheet feeding device, the motion transmission mechanism is provided on the cover member, and is rotatably provided on the first main body transmission gear that rotates together with the cover member, and the device main body. And a second motion transmission gear that meshes with the first motion transmission gear in the closing operation of the cover member, and a friction clutch that transmits the rotation of the second motion transmission gear to the first roller. It is.

  When the user opens the cover member to clear the paper jam and then closes the cover member, the first motion transmission gear rotates together with the cover member. Since the first motion transmission gear meshes with the second motion transmission gear, the second motion transmission gear also rotates in conjunction with the closing operation of the cover member. The rotation of the second motion transmission gear is transmitted to the first roller via the friction clutch, whereby the first roller rotates toward the sheet feeding reverse direction end of the idling range. If the first roller reaches the reverse feed end of the idling range before the cover member is completely closed, the friction clutch slips and rotates from the second motion transmission gear to the first roller. Transmission is interrupted.

  According to the present invention, in the sheet feeding device, the first motion transmission gear and the second motion transmission gear are meshed with the cover member in an open posture. When the user opens the cover member to clear a paper jam, the first roller can easily idle due to the engagement of the first motion transmission gear and the second motion transmission gear. Be regulated.

  According to the present invention, in the paper feeding device, the cover member has a rotation shaft disposed upstream of the second motion transmission gear in the paper feeding direction, and the downstream side of the paper feeding direction with respect to the rotational shaft is the center. It opens and closes. Thereby, since the rotation direction for closing the cover member and the rotation direction for returning the first roller are opposite, the configuration of the motion transmission mechanism is simplified.

  According to the present invention, in the sheet feeding device, the motion transmission mechanism is provided on the cover member, and is provided coaxially with the first motion transmission member that rotates together with the cover member and the first roller. And a second motion transmission member that frictionally conducts the rotation of the first motion transmission member.

  When the user opens the cover member to clear the paper jam and then closes the cover member, the first motion transmission member rotates together with the cover member. The rotation of the first motion transmission member is frictionally conducted to the second motion transmission member. Since the second motion transmission member is provided coaxially with the first roller, as the second motion transmission member rotates, the first roller rotates toward the sheet feed reverse direction end of the idling range. If the first roller reaches the reverse feed direction end of the idling range before the cover member is completely closed, the first motion transmission member and the second motion transmission member slide to transmit rotation. Blocked.

  In the sheet feeder, the first motion transmission member and the second motion transmission member may be in frictional contact with the cover member in an open position. When the user opens the cover member to clear a paper jam, the first roller easily idles due to frictional contact between the first motion transmission member and the second motion transmission member. Is regulated.

  According to the present invention, in the paper feeding device, the cover member has a rotation shaft disposed upstream of the second motion transmission member in the paper feeding direction, and the downstream side of the paper feeding direction with respect to the rotation shaft is the center. It opens and closes. Thereby, since the rotation direction for closing the cover member and the rotation direction for returning the first roller are opposite, the configuration of the motion transmission mechanism is simplified.

  Further, in the sheet feeder, the return unit rotates the first roller to the sheet feed reverse direction end of the idling range permitted by the clutch when the cover member is closed. Thus, it is a control means for controlling the drive mechanism. Thereby, the return means can be realized as software.

  According to the present invention, in the sheet feeding device, the control means detects that the cover member has closed after the cover sensor that detects opening / closing of the cover member detects opening of the cover member. The drive mechanism is driven in the forward feeding direction for a predetermined time.

  When the user opens the cover member to clear the paper jam, the cover sensor detects the opening of the cover member. When the cover member is closed, the cover sensor detects the closing of the cover member. Based on this detection signal, the control means drives the drive mechanism in the forward feeding direction for a predetermined time. The drive is transmitted to the clutch of the drive transmission mechanism, and the clutch rotates so that the first roller is directed toward the sheet feeding reverse direction end of the idling range. The clutch is rotated until at least the first roller reaches the reverse feed direction end of the idling range, and then the drive mechanism is stopped and the first roller is positioned at the feed reverse direction end of the idling range. It becomes.

  Preferably, in the sheet feeding device, the clutch of the drive transmission mechanism is a one-turn clutch that allows the first roller to idle about one turn.

  According to the present invention, in the sheet feeding device, the first abutting member is a pad-shaped member disposed at a position facing the first roller. Thus, the first contact member can be configured simply and the sheet can be reliably brought into contact with the first roller. In addition, the biasing force of the first contact member can be easily adjusted.

  As described above, according to the paper feeding device according to the present invention, when the leading edge of the paper set in the paper feeding tray is inserted into the suction chute, the first roller that contacts the leading edge of the paper idles within a predetermined range. The user hardly feels resistance when the leading edge of the sheet passes the position where the first roller is disposed, and can reliably insert the sheet to the insertion limit position. Thus, the paper set in the paper feed tray is reliably sent out in the paper feeding direction by the rotation of the first roller, and the paper is reliably fed. Further, the paper set in the paper feed tray can be pulled out without resistance, and the paper is not damaged at that time. Further, even if the cover member is opened to eliminate a paper jam and the first roller is unexpectedly rotated idly, the first roller is interlocked with the closing operation of the cover member. Since the clutch returns to the reverse feed direction end of the idling range allowed by the clutch, the paper is always reliably set in the paper feed tray.

Embodiments of the present invention will be described below with reference to the drawings as appropriate.
(First embodiment)
FIG. 1 shows an external configuration of a multifunction machine 1 according to the first embodiment of the present invention. The multi-function device 1 is a multi-function device (MFD: Multi Function Device) that integrally includes a scanner function, a printer function, and a facsimile function. The upper part of the multifunction device 1 is a scanner unit 2 for reading an image of a document, and the lower part of the multifunction device 1 is a printer unit 3 for recording an image on a recording sheet. The paper feeding device according to the present invention is realized as the ADF 5 of the scanner unit 2 of the multifunction machine 1. Therefore, the printer function or the like is an arbitrary mechanism in the present invention. For example, the paper feeding device according to the present invention may be realized as a single scanner having only the scanner function. Further, in the present embodiment, the present invention is implemented as a paper feeding device used for the ADF 5 of the scanner unit 2, but the use of the paper feeding device according to the present invention is not limited to the scanner. Naturally, it can be realized as a paper feeding device for feeding a recording paper or a document in a printer, a copying machine or the like.

Hereinafter, the configuration of the scanner unit 2 will be described in detail.
As shown in FIG. 1, the scanner unit 2 includes a document holding cover 6 having an auto document feeder (ADF) 5 with respect to a reading table 4 that functions as an FBS (Flatbed Scanner). It can be opened and closed through a hinge on the back side. The reading table 4 is configured as a housing of the multifunction machine 1, and a platen glass 20 (see FIG. 3) is disposed on the top surface facing the document pressing cover 6. An image reading unit 21 is built in the reading table 4 so as to face the platen glass 20. When the scanner unit 2 is used as an FBS, the document pressing cover 6 is opened to place a document on the platen glass 20, and the document pressing cover 6 is closed to fix the document on the platen glass 20. Thereafter, the image reading unit 21 is scanned along the platen glass 20 to read the image of the original.

  A pressing member 19 made of a sponge, a white plate, or the like is disposed on the lower surface of the document pressing cover 6 in order to press the document placed on the platen glass 20. Further, the function of the FBS is arbitrary in the sheet feeding device according to the present invention, and the present invention may be realized as the multifunction machine 1 having only the ADF 5.

  The document pressing cover 6 is provided with an ADF 5 that continuously conveys documents from the paper feed tray 22 to the paper discharge tray 23 via a predetermined conveyance path 26. In the conveyance process by the ADF 5, the document passes through the reading surface 42, and the image reading unit 21 reads the image of the document below the reading surface 42. The paper feeding device according to the present invention is realized in the ADF 5.

  An operation panel 7 is provided on the front side of the reading table 4. The operation panel 7 includes various operation buttons and a liquid crystal display unit, and the multifunction device 1 operates according to instructions from the operation panel 7. In addition to the instruction from the operation panel 7, the multifunction device 1 also operates according to an instruction connected to the computer and transmitted from the computer via a printer driver, a scanner driver, or the like.

  In addition, a slot portion 8 into which various small memory cards as recording media can be loaded is provided in the upper left part of the front surface of the multifunction device 1. The image data recorded on the small memory card loaded in the slot unit 8 can be read, information on the image data can be displayed on the liquid crystal display unit, and an arbitrary image can be recorded on the recording paper by the printer unit 3. The input for this can be performed from the operation panel 7.

  As shown in FIGS. 1 and 3, the paper feed tray 22 and the paper discharge tray 23 are configured in two upper and lower stages on the document pressing cover 6. The paper feed tray 22 is formed integrally with the upper surface of the document pressing cover 6. A document whose image is read by the ADF 5 is placed on the paper feed tray 22 so that a plurality of sheets are stacked and the front end in the paper feed direction is inserted into the ADF 5. In addition, a pair of document guides 24 are provided on the paper feed tray 22 so as to be slidable in the depth direction across the depth direction of the multifunction machine 1. The document guide 24 rises from the sheet feed tray 22 and regulates the position in the width direction of the document placed on the sheet feed tray 22, and either one of a pair of documents by a known interlocking mechanism. When the guide 24 is slid, the other document guide 24 is also slid in the opposite direction.

  That is, when the document width is narrow, if one document guide 24 on the front side of the multifunction machine 1 is slid to the back side, the other document guide 24 on the back side slides to the front side in conjunction with this. Moving. As a result, the document width regulated by the pair of document guides 24 can be reduced with the approximate center in the depth direction as the center. On the contrary, when the document width is wide, when one document guide 24 on the front side of the multifunction machine 1 is slid and moved to the front side, the other document guide 24 on the back side is linked to the back side. By sliding, the original width regulated by the pair of original guides 24 can be increased.

  A paper discharge tray 23 is integrally formed with the pair of document guides 24 so as to be separated from the paper feed tray 22 in the vertical direction. The document discharged from the ADF 5 is held on both sides of the document by the discharge tray 23 and is held in a state separated from the document on the sheet feed tray 22. Since the length of the paper discharge tray 23 in the paper discharge direction is shorter than the length of the document, the front end side of the document in the paper discharge direction is held on the paper feed tray 22 so as to hang down from the paper discharge tray 23. Accordingly, the leading end portion of the document in the paper discharge direction on the paper discharge tray 23 overlaps the rear end portion of the document in the paper feeding direction on the paper feed tray 22, but the leading end portion of the document in the paper feeding direction on the paper feed tray 22. And the rear end portion of the original on the paper discharge tray 23 in the paper discharge direction are held in two stages by the paper discharge tray 23, so that these originals are not confused. Further, by shortening the paper discharge tray 23, a necessary space on the document pressing cover 6 can be reduced, and the multifunction device 1 can be made thin and small.

  Further, as shown in FIG. 19, an arrow 19 indicating the insertion direction of the document to be placed on the paper feed tray 22 is marked on the upper surface of the paper feed tray 22. As described above, the paper discharge tray 23 disposed above the paper feed tray 22 is formed integrally with the pair of left and right document guides 24 and supports both ends in the width direction of the document discharged from the ADF 5. Is. Accordingly, as shown in FIG. 19, the paper discharge tray 23 does not exist above the substantially central portion in the width direction of the paper feed tray 22, and the user can visually recognize the arrow 19 from above the ADF cover 28. it can.

  As will be described later, a suction chute 29 is formed from the paper feed tray 22 to the inside of the ADF 5 (see FIGS. 2 and 3). 29 is placed on the paper feed tray 22. As shown in FIG. 19, a part of the tip end side of the arrow 19 reaches the suction chute 29 so that the position where the document should be inserted is the suction chute 29. It has become. Therefore, an erroneous operation in which the user inserts a document into the paper discharge chute 33 (see FIG. 3) is prevented. The display means indicated by the arrow 19 may be, for example, printed on the paper feed tray 22 or may have a concavo-convex shape on the upper surface of the paper feed tray 22.

  As shown in FIGS. 1 and 2, the end of the paper feed tray 22 on the side where the ADF 5 is not provided is integrated with the standing posture rising from the upper surface of the paper feed tray 22 and the upper surface of the paper feed tray 22. A document stopper 25 is provided for changing the posture to a lying posture. As shown in FIGS. 1 and 2, by placing the document stopper 25 in an upright position, for example, when a document having the same size as the paper feed tray 22 is discharged from the ADF 5, the document is stopped by the document stopper 25. It is restrained and is prevented from slipping down from the paper feed tray 22. In this way, by receiving the discharged document with the document stopper 25, the area of the sheet feed tray 22 can be reduced, and the document pressing cover 6 integrally formed with the sheet feed tray 22 can be downsized. Further, when the document stopper 25 is not necessary, by adopting a lying posture, the multifunction device 1 can be made compact when packed or stored without protruding from the document pressing cover 6.

  As shown in FIGS. 2 and 3, a conveyance path 26 is formed in a substantially U shape in the lateral direction inside the ADF 5 so as to connect the paper feed tray 22 and the paper discharge tray 23. The conveyance path 26 includes an ADF main body 27 (apparatus main body) formed integrally with the document pressing cover 6 and an ADF cover 28 (cover member) provided on the ADF main body 27 so as to be openable and closable. The suction chute portion 29 of the ADF 5 includes a guide plate 30 formed integrally with the ADF main body 27 so that the paper feed tray 22 is extended, and a partition plate 31 disposed inside the ADF cover 28. Is configured as a passage having a predetermined width in the vertical direction.

  The conveyance path 26 is formed in a substantially U shape in a lateral direction from the suction chute 29 to the discharge chute 33 through the curved portion 32. The curved portion 32 and the discharge chute 33 are also formed in the ADF main body 27, A passage having a predetermined width is continuously formed by the ADF cover 28, the partition plate 31, and the like. Accordingly, the document set on the paper feed tray 22 is guided to the suction chute portion 29 and fed to the curved portion 32, and is discharged from the paper discharge chute portion 33 to the paper discharge tray 23.

  Conveying means for conveying the document is disposed in the conveying path 26. Specifically, as shown in the drawing, the suction roller 34 (first roller), the suction nip piece 35 (first contact member) that is in pressure contact with the suction roller 34, the separation roller 36 (second roller), and the pressure contact with this. The separating nip piece 37 (second abutting member), the conveying roller 38, and the pinch roller 39 that is in pressure contact with the separating nip piece 37 constitute conveying means. The configuration of each roller and nip piece constituting the conveying means is an example, and the number and arrangement of rollers can be changed, or a pinch roller can be used in place of each nip piece, and other known conveying means can be changed. Of course.

  Of the above-described conveying means, the suction roller 34, the suction nip piece 35, the separation roller 36, and the separation nip piece 37 disposed in the suction chute 29 constitute a sheet feeding device according to the present invention. Hereinafter, these configurations will be described in detail.

  As shown in FIGS. 2 to 4, the suction roller 34 is rotatably provided at a substantially center of the suction chute 29 so that a part of the roller surface is exposed from the upper surface of the guide plate 30. Similarly, the separation roller 36 is rotatably provided at a position separated from the suction roller 34 in the paper feeding direction so that a part of the roller surface is exposed from the upper surface of the guide plate 30. A driving force from a conveyance motor 52 (see FIG. 5) is transmitted to the suction roller 34 and the separation roller 36 so as to be rotationally driven. The drive mechanism and the drive transmission mechanism will be described later. The suction roller 34 and the separation roller 36 have the same diameter and are rotated at the same peripheral speed. In addition, a one-round clutch 65 (see FIG. 8) is interposed in the drive transmission to the suction roller 34, and the suction roller 34 can idle for one round.

  The suction nip piece 35 is provided at a position opposed to the suction roller 34 of the partition plate 31 so as to be swingable in a direction in which the suction nip piece 35 contacts and separates from the suction roller 34. The suction nip piece 35 has a pad shape with a width slightly narrower than the roller width in the axial direction of the suction roller 34, and rotating shafts 40 are formed on both sides on the upstream side in the paper feeding direction. The rotation shaft 40 is pivotally supported by a shaft support portion 41 formed on the lower surface of the partition plate 31, so that the end portion on the downstream side in the sheet feeding direction advances and retreats so as to be able to contact the roller surface of the suction roller 34. The suction nip piece 35 is elastically biased downward by a spring member (not shown), and is always in contact with the suction roller 34 without nipping the document. A roller may be used in place of the pad-shaped suction nip piece 35, but by using a pad-shaped contact member, the contact member can be realized in a simple and space-saving manner. It is easy to adjust the elastic biasing force applied to the member.

  The separation nip piece 37 is provided at a position opposite to the separation roller 36 of the partition plate 31 so as to be able to swing in a direction in which the separation nip piece 37 contacts and separates from the separation roller 36. The separation nip piece 37 is a pad having a width slightly narrower than the roller width in the axial direction of the separation roller 36, and the end on the downstream side in the paper feeding direction is the separation roller with the upstream side in the paper feeding direction as a rotation shaft. It advances and retreats so that it can contact 36 roller surfaces. The separation nip piece 37 is elastically biased downward by a spring member (not shown), and is always in pressure contact with the roller surface of the separation roller 36 in a state where the document is not nipped. The roller may be brought into contact with the separation roller 36 instead of the pad-like separation nip piece 37. However, by using a pad-like contact member, the contact member can be realized in a simple and space-saving manner. In addition, it is easy to adjust the elastic biasing force applied to the contact member.

  The conveyance roller 38 is disposed in the curved portion 32 that is substantially U-shaped in the lateral direction of the conveyance path 26. The conveying roller 38 has an outer diameter such that the roller surface forms part of the curved portion 32. Similar to the suction roller 34 and the separation roller 36, the transport roller 38 is driven to rotate by receiving a driving force from the transport motor 52 (see FIG. 5).

  Around the conveying roller 38, pinch rollers 39 are provided at three locations. Each pinch roller is elastically biased by a spring piece, is rotatably supported by the ADF main body 27 or the ADF cover 28, and is in pressure contact with the roller surface of the transport roller 38. And if the conveyance roller 38 rotates, it will follow and the pinch roller 39 will also rotate. By these pinch rollers 39, the original is pressed against the conveying roller 38, and the rotational force of the conveying roller 38 is transmitted to the original.

  A paper discharge chute 33 is formed on the downstream side in the paper feed direction of the transport roller 38. The paper discharge chute 33 is formed between the ADF cover 28 and the partition plate 31 so as to be continuous with the curved portion 32 of the conveyance path 26 constituted by the inner surface of the ADF cover 28 and the conveyance roller 38. . Accordingly, the original supplied from the paper feed tray 22 to the conveyance path 26 is sequentially discharged through the suction chute portion 29, the curved portion 32, and the paper discharge chute portion 33 to the paper discharge tray 23.

  As shown in FIG. 2, the ADF cover 28 is provided so as to be rotatable upward from the suction roller 34 with the paper feed tray 22 side as a rotation axis. By opening the ADF cover 28, the guide plate 30 and the partition plate 31 are greatly separated, the suction chute portion 29 and the curved portion 32 are opened, the suction roller 34 and the separation roller 36, the suction nip piece 35, and the separation nip. The piece 37 is greatly separated. Therefore, by opening the ADF cover 28, it is possible to eliminate a paper jam generated in the transport path 26 and to perform maintenance inside the ADF 5. Further, the closing operation of the ADF cover 28 and the idling of the suction roller 34 are interlocked, and this motion transmission mechanism will be described later.

  As shown in FIG. 3, a platen glass 20 is disposed on the upper surface of the reading table 4. The platen glass 20 is used to place a document when the scanner unit 2 is used as an FBS, and is a transparent glass plate, for example. One end side of the platen glass 20 reaches to the lower side of the conveying roller 38, and also constitutes a reading surface 42 for reading an image using the ADF 5.

  An image reading unit 21 is built in the reading table 4. As shown in FIG. 3, the image reading unit 21 includes a CIS unit 43, a carriage 44, and a scanning mechanism (not shown). The CIS unit 43 is a so-called contact-type image sensor that irradiates a document with light and converts the reflected light from the document into an electric signal. The width direction is arranged with the reading direction as the reading direction.

  The CIS unit 43 is mounted on a carriage 44 and is in close contact with the platen glass 20. The carriage 44 is provided so as to be able to scan below the platen glass 20 by a scanning mechanism (not shown). When the scanner unit 2 is used as an FBS, the carriage 44 is scanned below the platen glass 20, so that the CIS unit 43 reads an image of a document placed on the platen glass 20. On the other hand, when the ADF 5 is used, as shown in the figure, the carriage 44 moves below the reading surface 42 and stops, and the CIS unit 43 reads an image of the document passing through the reading surface 42.

  In the present embodiment, since the scanner unit 2 is also used as an FBS, the image reading unit 21 can be scanned along the platen glass 20, but the FBS is an arbitrary function. When the invention is realized as a paper feeding device for reading an image using only the ADF 5, the image reading unit 21 may be installed at a position facing the conveying roller 38, and a scanning mechanism is unnecessary. In the present embodiment, the close contact type CIS unit 43 is used as the image reading unit 21. However, other known image reading units such as a reduction optical system CCD unit may be used. It is.

  FIG. 5 shows the configuration of the control unit 45 (control means) of the multifunction machine 1. The control unit 45 controls the overall operation of the multifunction machine 1 including not only the scanner unit 2 but also the printer unit 3. However, in the description of the present embodiment, the components of the printer unit 3 need not be described in detail, and thus the components of the printer unit 3 are omitted in FIG. As shown in the figure, the control unit 45 is configured as a microcomputer mainly including a CPU 46, a ROM 47, a RAM 48, and an EEPROM 49, and is connected to an ASIC (Application Specific Integrated Circuit) 51 via a bus 50.

  The ROM 47 stores a program for controlling various operations of the multifunction machine 1 and the like. The RAM 48 is used as a storage area or work area for temporarily recording various data used when the CPU 46 executes the program.

  The ASIC 51 generates a phase excitation signal and the like for energizing the transport (LF) motor 52 in accordance with a command from the CPU 46, applies the signal to the drive circuit 53 of the transport motor 52, and drives the drive signal via the drive circuit 53. , The rotation of the transport motor 52 is controlled.

  The drive circuit 53 drives the conveyance motor 52 connected to the separation roller 36 and the conveyance roller 38, and receives an output signal from the ASIC 51 and forms an electrical signal for rotating the conveyance motor 52. In response to the electrical signal, the conveyance motor 52 rotates, and the rotational force of the conveyance motor 52 is transmitted to the separation roller 36 and the conveyance roller 38 via a known drive mechanism including a gear, a drive shaft, and the like. The suction roller 34 is driven and transmitted from the separation roller 36 via a drive transmission mechanism.

  Similarly, the ASIC 51 generates a phase excitation signal for energizing the carriage (CR) motor 54 in accordance with a command from the CPU 46, and applies the signal to the drive circuit 55 of the carriage motor 54, via the drive circuit 55. The carriage motor 54 is controlled to rotate by energizing the carriage motor 54 with a drive signal.

  The drive circuit 55 drives the carriage motor 54 connected to the carriage 44, receives an output signal from the ASIC 51, and generates an electrical signal for rotating the carriage motor 54. The carriage motor 54 rotates in response to the electrical signal, and the rotational force of the carriage motor 54 is transmitted to the carriage 44 via a known scanning mechanism, whereby the carriage 44 is scanned.

  Further, the ASIC 51 includes a lead sensor 56 for detecting a document in the conveyance path 26, and a rotary encoder 57 and a movement amount of the carriage 44 provided to detect rotation amounts of the separation roller 36 and the conveyance roller 38. Are connected to a linear encoder 58 for detecting the open / closed state and a cover sensor 59 for detecting the opening / closing of the ADF cover 28.

  Further, the ASIC 51 includes a CIS 43 for reading an image of a document conveyed on the conveyance path 26, an operation panel 7 for instructing operation of the multifunction device 1, a slot portion 8 into which various small memory cards are inserted, a personal computer, and the like. The external interface is connected to a parallel interface and a USB interface for transmitting and receiving data via a parallel cable or a USB cable. Further, an NCU (Network Control Unit) and MODEM for realizing a facsimile function are also connected.

Hereinafter, the drive transmission mechanism from the separation roller 36 to the suction roller 34 will be described in detail.
FIG. 6 shows a state in which the guide plate 30 is removed. As shown in the drawing, the suction roller 34 and the separation roller 36 are located below the guide plate 30 (not shown in FIG. 6) on the ADF main body 27. The shafts 61 are respectively supported by the formed shaft support portions 61 and are arranged side by side in the paper feeding direction. Driving from the transport motor 52 is input to the shaft 62 of the separation roller 36. A drive transmission mechanism 63 for transmitting the drive from the transport motor 52 from the separation roller 36 to the suction roller 34 is disposed on one end side (the front side in the figure) of the shaft 62.

  As shown in FIGS. 6 and 7, the drive transmission mechanism 63 includes a gear 64 fitted on the shaft 62 of the separation roller 36, a one-round clutch 65 provided on one end side of the suction roller 34, and a gear 64. A drive transmission gear 66 that transmits drive to the one-round clutch 65 is configured. The gear 64 is a spur gear in which teeth parallel to the axis are formed on the outer periphery, and a fitting portion with the shaft 62 is formed in a D shape so as to rotate integrally with the shaft 62.

  As shown in FIGS. 8 and 9, the one-round clutch 65 mainly includes a clutch gear 67 and a locking piece 68. The clutch gear 67 is a spur gear having teeth formed parallel to the axis on the outer periphery. The shaft 70 of the suction roller 34 is inserted into a shaft hole 69 drilled in the axial direction, and rotates with respect to the shaft 70. It is free. A fitting groove 71 is formed in an arc shape along the outer periphery of the shaft hole 69 so as to penetrate in the axial direction. The fitting groove 71 is used for fitting the locking piece 68 and is formed in an arc shape that leaves a part in the circumferential direction where the locking portion 72 is formed. The locking portion 72 is for abutting against the locking piece 68 to transmit a driving force to the suction roller 34 via the locking piece 68, and the arcuate ends of the fitting groove 71. Make up surface.

  The locking piece 68 is a rod-like member protruding in the axial direction from one end face of the suction roller 34 to which the clutch gear 67 is fitted. The locking piece 68 protrudes from a position corresponding to the fitting groove 71 of the clutch gear 67 and has a length enough to protrude from the clutch gear 67 through the fitting groove 71.

  As shown in FIG. 9, the clutch gear 67 is fitted on the shaft 70 of the suction roller 34, and the locking piece 68 is inserted into the fitting groove 71 of the clutch gear 67 so that the suction roller 34 and the clutch gear are inserted. 67 is combined. As shown in the drawing, when the clutch gear 67 rotates counterclockwise in a state where the locking piece 68 is in contact with the locking portion 72 of the clutch gear 67 at the position on the counterclockwise direction side, The stop 72 pushes the locking piece 68 in the counterclockwise direction. Therefore, both the clutch gear 67 and the suction roller 34 rotate counterclockwise while maintaining the engaged state shown in the drawing.

  On the other hand, when the suction roller 34 is rotated counterclockwise while the clutch gear 67 is stationary, the locking piece 68 slides in the fitting groove 71, so that the clutch gear 67 does not rotate and remains stationary. Will remain. Then, when the suction roller 34 is rotated by approximately one turn, the locking piece 68 reaches the position in the clockwise direction of the locking portion 72 and comes into contact therewith. In order to further rotate the suction roller 34 counterclockwise from this state, the locking piece 68 pushes the locking portion 72 counterclockwise while the suction roller 34 and the clutch gear 67 are rotated counterclockwise. It will be rotated together.

  In this way, the one-round clutch 65 mainly composed of the clutch gear 67 and the locking piece 68 has the clutch gear 67 only for one round in which the locking piece 68 slides in the fitting groove 71 of the clutch gear 67. The idle roller 34 is allowed to idle regardless of the drive transmission. In the above description, the case where the suction roller 34 and the clutch gear 67 rotate counterclockwise has been described. However, even when they rotate clockwise, the suction roller 34 is allowed to idle for approximately one revolution. .

  As shown in FIGS. 6 and 7, a drive transmission gear 66 is interposed between the gear 64 provided on the shaft 62 of the separation roller 36 and the clutch gear 67 of the one-round clutch 65. The drive transmission gear 66 is a spur gear having teeth that are parallel to the axis on the outer periphery, and meshes with the gear 64 and the clutch gear 67. As a result, drive is transmitted from the gear 64 to the one-round clutch 65.

  In the present embodiment, the return means according to the present invention is mechanically realized by the motion transmission mechanism that transmits the rotational motion in the closing operation of the ADF cover 28 as the rotational motion of the suction roller 34. Hereinafter, a motion transmission mechanism that interlocks the closing operation of the ADF cover 28 and the idling of the suction roller 34 will be described in detail.

  The motion transmission mechanism rotates the suction roller 34 to the sheet feeding reverse direction end of the idling range permitted by the one-round clutch 65 based on a closing operation for changing the posture of the ADF cover 28 in the open posture to the closed posture. As shown in FIG. 10, a gear 73 (first motion transmission gear) provided on the ADF cover 28, and a gear 74 (second motion transmission gear) provided on the shaft 70 of the suction roller 34, , And a torque limiter 75 (friction clutch) disposed on the shaft 70. FIG. 10 shows a state in which the guide plate 30 and the like are removed for convenience of explanation.

  The gear 73 is a fan-shaped gear provided coaxially with the bearing 76 </ b> A of the ADF cover 28, and a spur gear having teeth formed parallel to the axis on the outer periphery. As shown in FIG. 10, the ADF main body 27 is formed with a shaft 76 so as to protrude inward in the horizontal direction. Bearings 76A are formed at positions corresponding to the shaft 76 at both ends in the width direction of the ADF cover 28, and the ADF cover 28 rotates relative to the ADF main body 27 when the bearing 76A supports the shaft 76. It is possible. The gear 73 is formed integrally with a bearing 76A on one end side of the ADF cover 28 so as to protrude substantially downward from the ADF cover 28, and rotates around the shaft 76 as the ADF cover 28 is opened and closed.

  The gear 74 is fixed to one end of the shaft 70 of the suction roller 34. In detail, the shaft 70 extends from the suction roller 34 toward the side where the gear 73 is provided, and is freely rotatable by a shaft support 77 formed on the ADF main body 27 near the gear 73. It is supported by. A gear 74 that meshes with the gear 73 is provided at the extended end of the shaft 70. The gear 74 is a spur gear having teeth formed parallel to the axis on the outer periphery, and a fitting portion with the shaft 70 is formed in a D shape so as to rotate integrally with the shaft 70.

  The torque limiter 75 is provided on the shaft 70 between the suction gear 34 and the gear 74, transmits the rotation of the shaft 70 between the suction gear 34 and the gear 74, and a load exceeding a predetermined value occurs. In this case, the rotation transmission is cut off. As the torque limiter 75, a known friction clutch can be used. For example, the torque limiter 75 may be configured as a disc clutch that transmits two torsional moments by opposing two discs and contacting the discs with a spring or the like. . If the friction coefficient of these discs and the biasing force by a spring or the like are adjusted as appropriate, the discs rotate and transmit rotation by the friction force up to a predetermined torque, and the disc slips when a load exceeding the predetermined torque is applied. This interrupts the rotation transmission. The configuration of such a friction clutch is an example, and other known configurations such as a conical clutch, a circumferential clutch, and a spring clutch can be employed.

  As shown in FIGS. 11 and 12, the bearing 76A of the ADF cover 28 is disposed on the upstream side in the paper feeding direction from the shaft 70 to which the gear 74 is fixed. As shown in the drawing, the downstream side in the sheet feeding direction opens and closes around a shaft 76 fitted to the bearing 76A.

  The gear 73 provided on the ADF cover 28 is in a closed position in which the ADF cover 28 is closed with respect to the ADF body 27 and an open position in which the ADF cover 28 is completely opened with respect to the ADF body 27. The fan 74 does not mesh with the gear 74. During the opening / closing operation of the ADF cover 28, the gear 73 and the gear 74 are engaged with each other, and the rotation of the ADF cover 28 is transmitted to the shaft 70 of the suction roller 34 via the gear 73 and the gear 74. Yes.

  As described above, since the bearing 76A of the ADF cover 28 is disposed upstream of the shaft 70 in the paper feeding direction, the ADF cover 28 is rotated counterclockwise in the drawing in order to close the ADF cover 28. It becomes. The gear 73 together with the ADF cover 28 also rotates counterclockwise about the shaft 76 that fits the bearing 76A, and the gear 74 that meshes with the gear 73 rotates clockwise, that is, in the reverse direction of paper feed. . Accordingly, since the rotation direction for closing the ADF cover 28 and the direction in which the suction roller 34 is rotated in the paper feeding reverse direction can be reversed, the configuration of the motion transmission mechanism is simplified.

Hereinafter, a paper feeding operation in reading an image of a document using the ADF 5 will be described.
When an image is read by the scanner unit 2 using the ADF 5, the document pressing cover 6 is closed with respect to the reading table 4 as shown in FIG. Further, as shown in FIG. 11, the ADF cover 28 is closed with respect to the ADF main body 27. Therefore, the gear 73 provided on the ADF cover 28 and the gear 74 provided on the shaft 70 of the suction roller 34 are not meshed with each other.

  Then, a document to be read is placed on the paper feed tray 22. The document may be one sheet or a plurality of sheets. For example, when reading images of a plurality of originals of the same size, the originals are stacked and aligned, and one end thereof is inserted into the suction chute portion 29 from the paper feed tray 22.

  The document inserted into the suction chute 29 first comes into contact with the suction roller 34 and the suction nip piece 35. At this time, as shown in FIG. 7, the suction roller 34 is in an engaged state in which the locking piece 68 contacts the locking portion 72 of the clutch gear 67 at a position on the counterclockwise direction side. Yes. In other words, the locking piece 68 of the suction roller 34 is in contact with the end of the idling range permitted by the fitting groove 71 of the one-round clutch 65 in the reverse direction of the paper feed. Therefore, the suction roller 34 can idle for one turn in the sheet feeding direction.

  The document that has come into contact with the suction roller 34 and the suction nip piece 35 is further inserted while the suction roller 34 is idled in the paper feeding direction and the suction nip piece 35 is retracted against the elastic biasing force of the spring member. Is done. At this time, since the suction roller 34 that is in contact with the document rotates idle as the document is inserted, the elastic biasing force of the spring member that biases the suction nip piece 35 is loaded on the document as a resistance force against the insertion. By appropriately adjusting the elastic biasing force of the spring member, the user can insert the document further into the back without feeling any resistance. Therefore, when the document comes into contact with the suction roller 34 and the suction nip piece 35, the position is not mistaken for the insertion limit position. The suction nip piece 35 presses the document from the top to the bottom and presses against the suction roller 34. However, since gravity acts on the document, the suction nip piece 35 is excessively sensitive to insertion of the document. It is not necessary to apply a strong elastic biasing force.

  While the suction roller 34 is idling, the original inserted further into the back of the suction chute 29 is then brought into contact with the separation roller 36 and the separation nip piece 37. Since the shaft 62 of the separation roller 36 has a load due to a drive transmission mechanism from the conveyance motor 52, in order to insert a document to the back of the separation roller 36, the separation roller 36 is rotated against the load, The document is slid on the roller surface of the separation roller 36. The load or sliding friction causes a feeling of resistance in inserting the document, and the user determines that the document has been inserted. The original is placed on the paper feed tray 22 with the leading end inserted into the suction chute 29, whereby the setting of the original is completed.

  Next, the user operates the operation panel 7 to instruct the multifunction device 1 to start reading an image of a document. The operation panel 7 is provided with, for example, a start button. By pressing the start button, the multifunction device 1 can be instructed to start image reading. In response to the instruction, the control unit 5 of the multifunction machine 1 drives the transport motor 52 via the drive circuit 53. In response to this, the rotational force of the transport motor 52 is input to the separation roller 36. As a result, first, the separation roller 36 starts to rotate, but since the leading edge of the document is not nipped by the separation roller 36 and the separation nip piece 37, the document is stopped at the document setting position without being fed.

  As described above, when the document is inserted, the suction roller 34 is idled in the paper feeding direction. Therefore, as shown in FIG. The position is advanced. When a rotational force is input to the shaft 62 of the separation roller 36 in this state, the gear 64 also rotates in the paper feeding direction, that is, counterclockwise together with the separation roller 36. In response to this rotation, the drive transmission gear 66 meshed with the gear 64 rotates clockwise, and in response to this rotation, the clutch gear 67 meshed with the drive transmission gear 66 counterclockwise, that is, feed Rotate in the paper direction.

  As shown in the figure, since the locking portion 72 and the locking piece 68 of the clutch gear 67 are separated from each other, even if the clutch gear 67 starts to rotate, the rotation is not immediately transmitted to the locking piece 68, The gear 67 idles the shaft 70 of the suction roller 34. Then, if the clutch gear 67 starts to rotate and the locking portion 72 rotates to a position where it comes into contact with the locking piece 68, the locking portion 72 rotates so as to push the locking piece 68 counterclockwise. Transmission begins. In response to this, the suction roller 34 rotates counterclockwise, that is, in the paper feeding direction.

  The leading edge of the document placed on the paper feed tray 22 is inserted deeper than the position where the suction roller 34 and the suction nip piece 35 are disposed, and is pressed against the roller surface of the suction roller 34 by the suction nip piece 35. Has been. Accordingly, when the suction roller 34 rotates, the document is fed in the paper feeding direction in response to the rotation.

  A plurality of documents are integrally urged to the suction roller 34 by the suction nip piece 35, but only the lowermost document is in contact with the roller surface of the suction roller 34, so that the document is placed on the suction roller 34. Receiving the rotational force, it is sent out in the paper feeding direction. As a result, the leading edge of the document enters between the separation roller 36 and the separation nip piece 37 and is nipped therebetween. The original is pressed against the roller surface of the separation roller 36 by the separation nip piece 37, receives the rotational force of the separation roller 36, and is further fed out in the paper feeding direction. When the lowermost original is sent out by the suction roller 34, the originals stacked on the lowermost original may be sent out due to the influence of static electricity or the like. Even if a plurality of originals enter between them, only the lowermost original receives the rotational force of the suction roller 34 and the separation roller 36, so that only the original is separated from the plurality of originals and conveyed. It is fed to the road 26.

  As shown in FIG. 3, the document fed in this way is guided by the conveyance path 26 and conveyed downward toward the reading surface 42. That is, the original is nipped by the conveyance roller 38 and the pinch roller 39 disposed immediately downstream of the separation roller 36, and is conveyed to the reading surface 42 by receiving the rotational force of the conveyance roller 38. In the conveyance path 26 where the leading edge of the document reaches the reading surface 42, the leading edge of the document is detected by the lead sensor 56, and the amount of the document is determined based on the encoder amount or the number of steps of the conveyance motor 52 that inputs rotational force to the conveyance roller 38. It is determined that the tip has reached the reading surface 42. When the leading edge of the document reaches the reading surface 42, the CIS unit 43 starts reading an image of the document passing through the reading surface 42.

  The original is further conveyed while the image is read by the CIS unit 43, the leading end side of the original is nipped by the conveying roller 38 and the pinch roller 39 immediately downstream of the reading surface 42, and the rear end side of the original is the conveying roller. In a state of being nipped between the pin 38 and the pinch roller 39 immediately upstream of the reading surface 42, the U-turn is conveyed so as to be reversed along the curved portion 32 by receiving the rotational force of the conveying roller 38. During this time as well, the CIS unit 43 reads the image of the document passing on the reading surface 42. Then, the lead sensor 56 detects the trailing edge of the document, and it is determined that the trailing edge of the document has reached the reading surface 42 based on the encoder amount or the number of steps of the conveying motor 52 that inputs the rotational force to the conveying roller 38. Is done. When the trailing edge of the document passes through the reading surface 42, the image reading by the CIS unit 43 is finished, and the document is discharged from the discharge chute 33 to the discharge tray 23.

  When all the originals placed on the paper feed tray 22 have been fed and the transport motor 52 is stopped, the suction roller 34 is also stopped. As described above, when the suction roller 34 is rotated in the paper feeding direction, the engagement piece 68 is in the engaged state in which the engagement piece 68 is in contact with the engagement portion 72 of the clutch gear 67 counterclockwise. The suction roller 34 stops in the engaged state. Accordingly, since the locking piece 68 is positioned at the end of the idling range allowed by the fitting groove 71 of the one-round clutch 65, the suction roller 68 is set when the document is set again on the sheet feeding tray 22. 34 can be idled by approximately one turn in the paper feeding direction, that is, counterclockwise. Therefore, similarly to the above, one end of the original can be inserted into the suction chute 29 until it comes into contact with the separation roller 36 and the separation nip piece 37, and the original can be set on the paper feed tray 22.

  As described above, when the document is set on the paper feed tray 22, the suction roller 34 is idled from the paper feed reverse direction end of the idling range to the paper feed forward direction, for example, as shown in FIG. 13. . Accordingly, it is possible to idle from the position in the reverse direction of paper feeding. For example, the user once sets the document on the paper feed tray 22, but the document may be pulled out from the suction chute 29 for the purpose of adding the document. In such a case, as the document is pulled out, the suction roller 34 idles in the reverse direction of the paper feed, so that the user can pull out the document from the suction chute portion 29 with almost no resistance.

  Further, when the ADF cover 28 is opened in order to clear a paper jam generated in the transport path 26 or to perform maintenance inside the ADF 5, the user may touch the suction roller 34 and rotate it. There is. As shown in FIG. 12, in the state where the ADF cover 28 is in the open posture, the guide plate 30 and the partition plate 31 are largely separated, the suction chute portion 29 and the curved portion 32 are opened, and the suction roller 34 And the suction nip piece 35 are greatly separated from each other. The roller surface of the suction roller 34 is exposed from the guide plate 30, and the suction roller 34 can be idled for approximately one round. Therefore, there is a risk that the user may accidentally touch the suction roller 34 when clearing a paper jam or performing maintenance work, and the suction roller 34 easily idles due to such contact.

  For example, at the time of paper jam clearance or maintenance work, as shown in FIG. 14, the engagement piece 68 is in contact with the engagement portion 72 of the clutch gear 67 from the clockwise side, that is, It is assumed that the suction roller 34 is idled to a state where the fitting groove 71 of the one-round clutch 65 is positioned at the end of the idling range permitted by the feed forward direction. If the original is set in the paper feed tray 22 in this engaged state, the suction roller 34 cannot idle in the paper feed direction, so that when the original comes into contact with the suction roller 34, There is a sense of resistance in the insertion, and the user may misunderstand that the insertion of the document has been completed.

  Thus, when the ADF cover 28 is closed from the state where the suction roller 34 is idling, the gear 73 rotates together with the ADF cover 28, and the gear 73 and the gear 74 are engaged with each other as shown in FIG. Thereby, the rotational motion of the ADF cover 28 is transmitted to the shaft 70 of the suction roller 34 via the gear 73 and the gear 74.

  In the closing operation of the ADF cover 28, the gear 73 rotates counterclockwise about the shaft 76, and the gear 74 meshing with the gear 73 rotates clockwise. Therefore, the suction roller 34 is rotated together with the shaft 70 in the clockwise direction, that is, in the paper feeding reverse direction. As shown in FIG. 14, since the locking portion 72 does not exist on the clockwise side of the locking piece 68, the locking piece 68 slides on the fitting groove 71 of the clutch gear 67. Rotate clockwise.

  When the ADF cover 28 is in the closed position, the locking piece 68 is in an engaged state in which the locking piece 68 is in contact with the locking portion 72 of the clutch gear 67 counterclockwise. Accordingly, since the locking piece 68 returns to the end of the idling range permitted by the fitting groove 71 of the one-round clutch 65, the suction piece 68 is sucked when the document is set on the sheet feeding tray 22 after the ADF cover 28 is closed. The roller 34 can idle for about one turn in the paper feeding direction, that is, counterclockwise. Therefore, similarly to the above, one end of the document can be inserted into the suction chute 29 until it contacts the separation roller 36 and the separation nip piece 37, and the document can be set on the paper feed tray 22.

  As described above, the gear 73 provided in the ADF cover 28 is in the order of feeding in the idling range allowed by the fitting groove 71 of the one-round clutch 65 with respect to the gear 74 provided on the shaft 70 of the suction roller 34. It is preferable to set the gear ratio so as to allow the suction roller 34 positioned at the direction end to rotate only to slide to the end in the paper feed reverse direction. In addition, depending on the amount of idle rotation of the suction roller 34 during paper jam clearing or maintenance work, the suction roller 34 may move to the reverse feed direction end of the idle rotation range before the ADF cover 28 is completely closed. In such a case, the torque limiter 75 blocks the rotation transmission from the gear 74 to the suction roller 34. Therefore, the ADF cover 28 can be rotated to the closed position with the suction roller 34 positioned at the end of the idling range in the reverse direction of the paper feed.

  As described above, according to the sheet feeding device realized in the multifunction machine 1, when the leading edge of the document set on the sheet feeding tray 22 is inserted into the suction chute portion 29, the suction roller 34 that contacts the leading edge of the document is within a predetermined range. Therefore, the user hardly feels resistance when the leading end of the document passes through the position where the suction roller 34 is disposed, and can reliably insert the document to the insertion limit position. As a result, the document set on the sheet feed tray 22 is reliably sent out in the sheet feeding direction by the rotation of the suction roller 34, and the document is reliably fed.

  Further, the original set on the paper feed tray 22 can be pulled out without resistance, and the original is not damaged at that time. Further, even if the ADF cover 28 is opened to clear a paper jam and the suction roller 34 is unexpectedly rotated idly, the suction roller 34 is interlocked with the closing operation of the ADF cover 28 and the one-round clutch 65 Therefore, the document is always set on the sheet feed tray 22 reliably.

Hereinafter, modifications of the first embodiment will be described.
This modification is obtained by changing the gear 73 in the first embodiment, and other configurations are the same. Therefore, only the configuration of the changed part will be described in detail.

  As shown in FIGS. 15 and 16, the ADF cover 28 is provided with a gear 78 instead of the gear 73. The gear 78 is a fan-shaped gear provided coaxially with the bearing 76 </ b> A of the ADF cover 28, and has teeth that are parallel to the axis on the outer periphery. The gear 78 is integrally formed with a bearing 76A on one end side of the ADF cover 28 so as to protrude substantially downward from the ADF cover 28, and a shaft 76 that fits with the bearing 76A as the ADF cover 28 opens and closes. Rotate around.

  15, the gear 78 does not mesh with the gear 74 in the closed position in which the ADF cover 28 is closed with respect to the ADF main body 27. However, as shown in FIG. In the open position where the cover 28 is completely open, the fan 28 is engaged with the gear 74. Of course, the gear 73 and the gear 74 are meshed even during the opening / closing operation of the ADF cover 28. Therefore, even if the ADF cover 28 is opened, the shaft 70 of the suction roller 34 and the ADF cover 28 are in an interlocked state.

  As a result, the ADF cover 28 is opened for paper jam clearance and maintenance work, and even if the user touches the suction roller 34, the ADF cover 28 is rotated together to rotate the suction roller 34. It is necessary to apply a load at which the torque limiter 75 starts to slide. Therefore, when the user touches the suction roller 34 inadvertently, the suction roller 34 does not rotate, and if the ADF cover 28 is closed, the suction roller 34 is supplied within the idling range permitted by the one-round clutch 65. As described above, it is positioned at the end in the reverse direction of the paper, and the subsequent setting of the original on the paper feed tray 22 is ensured.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described.
In the second embodiment, the configuration of the motion transmission mechanism in the first embodiment is changed, and the other configurations are the same. Therefore, only the configuration of the changed part will be described in detail.

  The motion transmission mechanism according to the present embodiment is obtained by changing the motion transmission mechanism by the gear 73, the gear 74, and the torque limiter 75 in the first embodiment to friction conduction. Specifically, the motion transmission mechanism is configured to feed the suction roller 34 in the reverse feed direction end of the idling range permitted by the one-round clutch 65 based on a closing operation for changing the posture of the ADF cover 28 in the open posture to the closed posture. As shown in FIG. 17, a fan-shaped wheel 79 (first motion transmission member) provided on the ADF cover 28 and a cylindrical wheel 80 (first wheel) provided on the shaft 70 of the suction roller 34 are provided. 2 motion transmission members).

  The fan-shaped wheel 79 is a fan-shaped flat wheel provided coaxially with the bearing 76A of the ADF cover 28, and the outer peripheral surface is a friction conducting surface. The fan-shaped wheel 79 is integrally formed with a bearing 76A on one end side of the ADF cover 28 so as to protrude substantially downward from the ADF cover 28, and is fitted to the bearing 76A as the ADF cover 28 is opened and closed. It rotates about the axis 76.

  The cylindrical wheel 80 is provided at the extending end of the shaft 70 of the suction roller 34 so as to be in press contact with the fan-shaped wheel 79. The gear 74 is a cylindrical car whose outer peripheral surface is a friction conducting surface, and a fitting portion with the shaft 70 is formed in a D shape so as to rotate integrally with the shaft 70.

  As described above, when the ADF cover 28 is opened, the user touches and rotates the suction roller 34 to clear a paper jam that has occurred in the transport path 26 or to perform maintenance inside the ADF 5. However, when the ADF cover 28 is closed while the suction roller 34 is idling, the fan wheel 79 rotates together with the ADF cover 28, and as shown in FIG. The vehicle 80 is in press contact. As a result, the rotational movement of the ADF cover 28 is frictionally transmitted to the shaft 70 of the suction roller 34 via the fan-shaped wheel 79 and the cylindrical wheel 80.

  In the closing operation of the ADF cover 28, the sector wheel 79 rotates counterclockwise about the shaft 76, and the cylindrical wheel 80 that is in pressure contact with the sector wheel 79 rotates clockwise. Therefore, the suction roller 34 is rotated together with the shaft 70 in the clockwise direction, that is, in the paper feeding reverse direction. When the ADF cover 28 is in the closed posture, as shown in FIG. 7, the suction roller 34 returns to the end in the reverse feed direction of the idling range permitted by the fitting groove 71 of the one-round clutch 65. When the document is set on the paper feed tray 22 after closing 28, the suction roller 34 can be idled by approximately one turn in the paper feed direction, that is, counterclockwise. Therefore, similarly to the above, one end of the original can be inserted into the suction chute 29 until it comes into contact with the separation roller 36 and the separation nip piece 37, and the original can be set on the paper feed tray 22.

  In addition, depending on the amount of idle rotation of the suction roller 34 during paper jam clearing or maintenance work, the suction roller 34 may move to the reverse feed direction end of the idle rotation range before the ADF cover 28 is completely closed. May reach. Since the suction roller 34 has a load of the driving mechanism via the clutch gear 67, the fan-shaped wheel 79 and the cylindrical wheel 80 are slid by the load and the frictional conduction is cut off. Therefore, the ADF cover 28 can be rotated to the closed position with the suction roller 34 positioned at the end of the idling range in the reverse direction of the paper feed.

  As described above, the motion transmission mechanism according to the second embodiment can achieve the same effects as those of the first embodiment. Although not shown in the drawing, as in the modification of the first embodiment, the fan-shaped wheel 79 is a cylindrical wheel 80 in a closed position in which the ADF cover 28 is closed with respect to the ADF main body 27. In an open posture in which the ADF cover 28 is completely opened with respect to the ADF main body 27 without being in press contact with the ADF main body 27, the fan shape may be in press contact with the cylindrical wheel 80.

  According to this, in order to rotate the suction roller 34 even if the user touches the suction roller 34 even if the ADF cover 28 is opened for the purpose of clearing a paper jam or for maintenance work, the ADF cover 28 is used. It is necessary to rotate them together or to apply a load that causes the fan-shaped wheel 79 and the cylindrical wheel 80 to slide. Therefore, when the user touches the suction roller 34 inadvertently, the suction roller 34 does not rotate, and if the ADF cover 28 is closed, the suction roller 34 is supplied within the idling range permitted by the one-round clutch 65. As described above, it is positioned at the end in the reverse direction of the paper, and the subsequent setting of the original on the paper feed tray 22 is ensured.

(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described.
In the third embodiment, the return means realized by the motion transmission mechanism in the first embodiment is realized as software, and the other configurations are the same. Therefore, only the configuration of the changed part will be described in detail.

  As described above, the ADF cover 28 can be opened and closed with respect to the ADF main body 27, and the opening and closing of the ADF cover 28 is detected by the cover sensor 59 as shown in FIG. As the cover sensor 59, for example, a known sensor such as an optical sensor or a magnet sensor that detects a filler provided on the ADF cover 28 can be adopted.

  The return means according to the present embodiment is realized by the control unit 45, and when the ADF cover 28 is closed, the suction roller 34 is positioned at the reverse feed direction end of the idling range permitted by the one-round clutch 65. Thus, the rotation of the drive mechanism is controlled.

  FIG. 18 is a flowchart showing control of the drive mechanism by the control unit 45. The ADF 5 of the scanner unit 2 is in a state where there is no document on the paper feed tray 22, and is in a state of waiting for start of document setting and image reading.

  From this state, when the ADF cover 28 is opened in order to clear a paper jam that has occurred in the transport path 26 or to perform maintenance inside the ADF 5, the cover sensor 59 indicates that the ADF cover 28 is in the open position. Detect (S1). The user performs jam processing and maintenance with the ADF cover 28 in the open position. Also at this time, since the suction roller 34 can be idled within a range permitted by the one-turn clutch 65, the user unexpectedly touches the suction roller 34, for example, as shown in FIG. The suction roller 34 may be idled until it is positioned at the end of the idling range permitted by the groove 71 in the feed forward direction.

  Thus, when the ADF cover 28 is closed from the state where the suction roller 34 is idling, the cover sensor 59 detects that the ADF cover 28 is in the closed posture (S2). Upon receiving this detection signal, the controller 45 causes the transport motor 52 to rotate forward for a predetermined time via the drive circuit 53 (S3). Here, the forward rotation direction of the transport motor 52 is a direction in which the suction roller 34 and the separation roller 36 are rotated in the forward feeding direction.

  When a driving input is made from the conveyance motor 52 to the shaft 62 of the separation roller 36, the gear 64 rotates together with the shaft 62 in the forward feeding direction, that is, counterclockwise in FIG. Then, the drive transmission gear 66 that meshes with the gear 64 rotates clockwise, and the clutch gear 67 that meshes with the drive transmission gear 66 rotates counterclockwise. As shown in the figure, since the locking piece 68 does not exist on the counterclockwise side of the locking portion 72 of the clutch gear 67, the clutch gear 67 slides the locking piece 68 in the fitting groove 71. In this way, it rotates with respect to the shaft 70 of the suction roller 34. That is, only the clutch gear 67 rotates counterclockwise while the suction roller 34 is stationary.

  Then, when the clutch gear 67 rotates approximately one round, as shown in FIG. 7, the engaging portion 72 of the clutch gear 67 is in contact with the locking piece 68 in the clockwise direction. It becomes. That is, the locking piece 68 returns to the end in the sheet feeding reverse direction of the idling range permitted by the fitting groove 71 of the one-round clutch 65. Further, when the conveyance motor 52 is rotated, driving is transmitted from the locking portion 72 to the locking piece 68, and the suction roller 34 rotates counterclockwise, that is, in the forward feeding direction.

  As described above, after the transport motor 52 is rotated forward for a time sufficient for the suction roller 34 to return to the end of the idle rotation range permitted by the fitting groove 71 of the one-round clutch 65, the controller 45 The drive of the conveyance motor 52 is stopped (S4). Then, it returns to the standby state for the subsequent document setting and image reading start.

  As a result, when the document is set on the paper feed tray 22 after the ADF cover 28 is closed, the suction roller 34 can idle for about one turn in the paper feed direction, that is, counterclockwise. Therefore, similarly to the above, one end of the original can be inserted into the suction chute 29 until it comes into contact with the separation roller 36 and the separation nip piece 37, and the original can be set on the paper feed tray 22.

  Note that each of the above embodiments is merely an example of the present invention, and it is needless to say that the embodiments can be appropriately changed without departing from the gist of the present invention.

FIG. 1 is a perspective view showing an external configuration of a multifunction machine 1 according to the first embodiment of the present invention. FIG. 2 is an enlarged perspective view showing an external configuration of the multifunction machine 1 with the ADF cover 28 opened. FIG. 3 is a cross-sectional view taken along the line AA showing the main configuration of the ADF 5. FIG. 4 is a perspective view showing the configuration of the suction chute 29 with the ADF cover 28 opened. FIG. 5 is a block diagram illustrating a configuration of the control unit 45. FIG. 6 is an enlarged perspective view showing the configuration of the drive transmission mechanism 63. FIG. 7 is a schematic diagram showing the configuration of the drive transmission mechanism 63. FIG. 8 is an exploded perspective view showing the configuration of the one-round clutch 65. FIG. 9 is an enlarged perspective view showing the configuration of the one-round clutch 65. FIG. 10 is an enlarged perspective view showing the configuration of the motion transmission mechanism. FIG. 11 is a BB cross-sectional view showing the main configuration of the ADF 5 with the ADF cover 28 closed. FIG. 12 is a BB cross-sectional view showing the main configuration of the ADF 5 with the ADF cover 28 opened. FIG. 13 is a schematic diagram illustrating the configuration of the drive transmission mechanism 63 in a state where the suction roller 34 is idling. FIG. 14 is a schematic diagram illustrating the configuration of the drive transmission mechanism 63 in a state where the suction roller 34 is idling. FIG. 15 is a cross-sectional view taken along the line BB showing a modification of the first embodiment. FIG. 16 is a cross-sectional view taken along the line BB showing a modification of the first embodiment. FIG. 17 is an enlarged perspective view showing the configuration of the motion transmission mechanism according to the second embodiment. FIG. 18 is a flowchart showing the operation of the third embodiment. FIG. 19 is a plan view of the document pressing cover 6. FIG. 20 is a diagram illustrating a schematic configuration of a conventional paper feeding device 91.

Explanation of symbols

22 ... Feed tray 26 ... Conveying path 27 ... ADF main unit (device main unit)
28 ... ADF cover (cover member)
29 ... Suction chute 34 ... Suction roller (first roller)
35 ... Suction nip piece (first contact member)
36: Separation roller (second roller)
37: Separation nip piece (second contact member)
45 ... Control unit (control means)
52 ... Conveyance motor (drive mechanism)
59 ... cover sensor 63 ... drive transmission mechanism 65 ... one-round clutch 73, 78 ... gear (first motion transmission gear)
74 ... Gear (second motion transmission gear)
75 ... Torque limiter (friction clutch)
76 ... Rotating shaft 79 ... Fan-shaped wheel (first motion transmission member)
80 ... Cylindrical wheel (second motion transmission member)

Claims (12)

A paper feed tray capable of stacking multiple sheets of paper to be fed;
A suction chute having guide surfaces facing each other with a predetermined width and guiding the paper from the paper feed tray to the conveyance path;
A first roller disposed on one of the guide surfaces of the suction chute so as to expose a part of the roller surface, abutting against the paper stacked on the paper feed tray and feeding the paper into the conveyance path; ,
A first abutting member that is provided on the other guide surface of the suction chute so as to be able to come into contact with and separate from the first roller and is elastically biased so as to abut against the first roller;
A sheet that is disposed on one of the guide surfaces of the suction chute and is spaced from the first roller in the paper feeding direction, with a part of the roller surface exposed and fed by the first roller. A second roller for feeding further in the paper feeding direction;
A second abutting member that is provided on the other guide surface of the suction chute so as to be able to contact and separate from the second roller and is elastically biased so as to abut against the second roller;
A drive mechanism for inputting a rotational force to the second roller;
A drive transmission mechanism having a clutch that allows the first roller to idle in a predetermined range and transmits the rotation of the second roller to the first roller;
One of the opposing guide surfaces of the suction chute is configured so as to be openable and closable with respect to the apparatus main body, the first roller, the second roller, the first contact member, A cover member that opens the suction chute so that the second contact member is spaced apart;
And a return means for rotating the first roller to the sheet feed reverse direction end of the idling range allowed by the clutch based on a closing operation for changing the position of the cover member in the open position to the closed position. Paper feeding device.   The sheet feeding device according to claim 1, wherein the return unit is a motion transmission mechanism that transmits a rotational motion in the closing operation of the cover member as a rotational motion of the first roller.   The motion transmission mechanism is provided in the cover member, and is provided in a first motion transmission gear that rotates together with the cover member, and is rotatably provided in the apparatus main body, and the first motion in the closing operation of the cover member. The sheet feeding device according to claim 2, further comprising: a second motion transmission gear that meshes with the transmission gear; and a friction clutch that transmits rotation of the second motion transmission gear to the first roller.   The sheet feeding device according to claim 3, wherein the first motion transmission gear and the second motion transmission gear are engaged with each other in a state where the cover member is in an open posture.   5. The cover member according to claim 3, wherein a rotation shaft is disposed upstream of the second motion transmission gear in the paper feeding direction, and the downstream side of the paper feeding direction opens and closes around the rotation shaft. Paper feeder.   The motion transmission mechanism is provided on the cover member, is provided coaxially with the first motion transmission member that rotates together with the cover member, and the first roller, and the first motion transmission member rotates. The sheet feeding device according to claim 2, further comprising a second motion transmission member that is frictionally conductive.   The sheet feeding device according to claim 6, wherein the first motion transmission member and the second motion transmission member are in frictional contact with the cover member in an open position.   8. The cover member according to claim 6, wherein a rotation shaft is disposed upstream of the second movement transmission member in the paper feeding direction, and the downstream side of the paper feeding direction opens and closes around the rotation shaft. Paper feeder.   The return means is a control means for controlling the drive mechanism so that when the cover member is closed, the first roller is rotated to the end of the idling range permitted by the clutch in the feed reverse direction. The paper feeding device according to claim 1.   The control means detects the closing of the cover member after the cover sensor that detects opening and closing of the cover member detects the opening of the cover member, and then moves the drive mechanism in the forward feeding direction for a predetermined time. The sheet feeding device according to claim 9, which is driven.   The sheet feeding device according to any one of claims 1 to 10, wherein the clutch of the drive transmission mechanism is a one-turn clutch that allows the first roller to idle approximately one turn. The sheet feeding device according to any one of claims 1 to 11, wherein the first abutting member is a pad-shaped member disposed at a position facing the first roller.

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