JP4549963B2 - Automatic document feeder - Google Patents

Description

  The present invention relates to an automatic document feeder that feeds a document to an image reading unit of an image forming apparatus such as a facsimile, a copying machine, or a scanner.

  Many automatic document feeders that feed a document to a reading unit of an image forming apparatus such as a facsimile, a copying machine, and a scanner have an upper conveyance path of a sheet feeding unit to ensure ease of jam processing and maintenance. It includes a paper feed upper guide to be formed, a paper feed cover that is an exterior of the paper feed unit, and a paper feed inlet lower guide that is the lower conveyance path of the paper feed inlet. It is comprised so that the conveyance path of a part can be exposed.

  However, in the automatic document feeder configured to expose the conveyance path, when the pickup roller that calls the document from the stacking unit and conveys the document to the sheet feeding unit is operated, the lower guide of the sheet feeding inlet is moved upward. Therefore, when the paper feed inlet guide is rotatable, an impact sound or vibration may occur due to looseness attached to the rotation shaft.

  Therefore, conventionally, by providing a thin elastic sheet on the guide plate facing the pickup roller and attaching the elastic sheet to the guide plate so as to define a gap with respect to the guide plate, There is known an automatic document feeder that suppresses impact sound and vibration and prevents the feeding means from rebounding to prevent a loss time until the start of feeding (for example, see Patent Document 1).

  Further, the lowering of the pickup roller is restricted during the lowering, and the lowering restricting operation for reducing the lowering speed after the restriction is executed, so that the pickup roller or other feeding member substantially lowers toward the sheet bundle. There is known an automatic document feeder that reduces impact noise and vibration when a feeding member falls on a sheet bundle even when the sheet bundle is thin by reducing the drop start height (for example, , See Patent Document 2).

JP 2002-240963 A JP 2001-220026 JP

  However, in the technique shown in Patent Document 1, since the thin elastic sheet is attached to the document conveying surface, the thin elastic sheet is worn, deteriorated, and damaged, which may cause document jam. Moreover, in the technique shown in Patent Document 2, there is a problem that productivity is lowered because the time required for the feeding member to descend becomes longer.

  SUMMARY An advantage of some aspects of the invention is that it provides an automatic document feeder capable of preventing an impact sound and vibration when a conveyance path is closed.

  An automatic document feeder according to the present invention includes an upper sheet feed guide unit that forms an upper conveyance path of a sheet feeding unit and is openable and closable so as to open and close the upper conveyance path; A pick-up roller that contacts and separates from the original bundle and calls the uppermost original of the original bundle, and an end portion thereof is arranged close to the pickup roller, and forms a lower conveyance path at the entrance of the paper feed unit In addition, a lower sheet feed inlet guide unit provided to be openable and closable with the end portion as a rotation shaft so as to open and close the lower conveyance path, and the upper sheet feed guide unit and the lower sheet feed guide unit are held. The lower sheet feeding inlet guide unit is rotatably held by the holding member with a drive shaft provided on the holding member as a rotation axis. The back side of the end portion adjacent to the pick-up roller unit, is characterized in that a first elastic member.

  With this configuration, since the first elastic member absorbs an impact when the upper guide unit is closed and the pickup roller comes into contact with the lower guide unit of the paper feed inlet, the first elastic member is deteriorated by the conveyance of the original. The impact of the pickup roller can be absorbed without any trouble. In addition, the sheet feed inlet lower guide unit rotates about a drive shaft provided on the holding member (for example, a shaft that drives a transport roller, a switching claw, and the like) as a rotation axis. It can be shared as the rotation axis of the sheet feed inlet lower guide unit, and the structure can be simplified.

  The automatic document feeder according to the present invention is characterized in that a rotatable member is provided around the drive shaft, and the rotatable member is brought into contact with the first elastic member.

  With this configuration, the rotating member that contacts the first elastic member rotates around the drive shaft, so that the contact between the first elastic member and the rotating member does not hinder the rotation of the drive shaft.

  The automatic document feeder of the present invention is characterized in that a second elastic member is provided around the rotating member, and the second elastic member is brought into contact with the first elastic member.

  With this configuration, the second elastic member that contacts the first elastic member is provided in the rotating member, and the rotating member rotates around the drive shaft. Therefore, the first elastic member and the rotating member This does not interfere with the rotation of the drive shaft.

  In the automatic document feeder of the present invention, the axial width of the drive shaft of the first elastic member and the second elastic member is larger than the axial width of the drive shaft of the rotating member. Is also small.

  With this configuration, the first elastic member or the second elastic member does not interfere with rotation of the drive shaft by contacting the drive shaft, for example, by protruding from a predetermined position.

  The automatic document feeder of the present invention is characterized in that it includes a restricting member that restricts the position of the rotating member in the axial direction of the drive shaft.

  With this configuration, since the position of the rotating member provided around the second elastic member does not move, the rotating member or the second elastic member is always used as the first elastic member stably. The impact of the pick-up roller can be absorbed.

  According to the present invention, it is possible to provide an automatic document feeder capable of preventing an impact sound and vibration when closing a conveyance path.

  As shown in FIG. 1, in the automatic document feeder 200, a document bundle is set on the document table 1 with the document surface facing upward, and the leading end of the document bundle is set to a stop claw 2 (the state at the time of setting is 2). When the document set filler 31 is set against the dotted line (shown by a dashed line), the angle of the document set filler 31 is changed from the broken line state to the solid line state, and the document set sensor 19 detects the document set. Further, the width direction of the original bundle is positioned in a direction perpendicular to the conveyance direction by a side fence (not shown). The outline of the automatic document feeder 200 will be described below with reference to the block diagram of FIG. 2 and the flowcharts of FIGS. Note that the step number describes only main processing.

  When a print key is pressed from a main body operation unit (not shown) and a document feed signal is transmitted from the main body control unit 111 to the controller 100 of the automatic document feeder 200, it is confirmed whether a document is set (step S1), the calling motor 101 is driven forward (step S2), and the pawl home position sensor 34 retracts the stop pawl 2 downward (solid line state shown in FIG. 1) (step S3).

  Next, the call motor 101 is driven in the reverse direction (step S4), and when it is confirmed that it is the pickup call position (step S5), the pickup home position sensor 33 lowers the pickup roller 3 so as to hold the document bundle from above. Thus, the calling motor is stopped (step S6).

  Next, an outline of the length in the document transport direction is determined by the document length sensors 20, 21, and 22 provided on the document table 1 (a sensor arrangement that can determine at least whether the document size is vertical or horizontal). ), A rough determination of the document size is performed based on the combination with the document width detection result (step S7).

  The pickup roller 3 is driven to rotate in the direction in which the uppermost document is conveyed to the sheet feeding port by the normal rotation of the sheet feeding motor 102, and several (ideally one) documents on the document table 1 are fed to the sheet feeding belt. 5 and the reverse roller 4 are fed to the original separation unit (step S8).

  The paper feed belt 5 is driven in the paper feed direction by the forward rotation of the paper feed motor 102, and the reverse roller 4 is driven to rotate in the reverse direction to the paper feed, separating the uppermost document and the original document below it, Only a document can be fed.

  When the original separated by the action of the paper feed belt 5 and the reverse roller 4 is further fed by the paper feed belt 5, the leading edge is detected by the abutment sensor 24 (step S9). When the leading edge is detected, the document is conveyed by a predetermined amount from the point of detection (step S10), and the forward drive of the paper feed motor 102 is stopped. At this time, by making the above-mentioned predetermined amount larger than the distance from the abutment sensor 24 to the pull-out roller 6, the document is stopped in a state where the pull-out roller 6 is formed with a certain amount of bending. At this time, by rotating the call motor 101 (step S13), the pickup roller 3 is retracted from the upper surface of the document (step S14), the call motor is stopped (step S15), and the document is transported by the paper feeding belt 5. Thus, the leading edge of the document enters the nip between the pull-out roller 6 and the driven roller 7 and corrects the bending (skew) of the document that occurs during separation feeding.

  The pull-out roller 6 has the skew correction function and is a roller for conveying the skew-corrected document after separation to the reading entrance roller 8, and is driven by reverse rotation of the paper feed motor 102. The pull-out roller 7 is driven when the paper feed motor 102 rotates in the reverse direction, but the pickup roller 3 and the paper feed belt 5 are not driven by the action of a one-way clutch (not shown). A plurality of document width sensors 25 are arranged in the depth direction and acquire information in the width direction perpendicular to the transport direction of the document transported by the pull-out roller 6 (step S19). The size information of the bundle of documents stacked on the document table 1 in the main body control unit 111 by the combination of the length information and the width information acquired from the detection results of the document length sensors 20, 21, and 22 on the document table 1 described above. Is transmitted (step S21).

  The exact length in the document transport direction is calculated by counting the number of motor drive pulses (step S16). When the document is conveyed to the reading entrance roller 8 by driving the pull-out roller 6, the document conveying speed is set to a high speed and the processing time for feeding the document to the reading unit is shortened. In this document, productivity can be improved by shortening the paper gap with the previous document by this high-speed conveyance.

  When the leading edge of the document is detected by the reading entrance sensor 26 (step S22), deceleration is started before the leading edge of the document enters the reading entrance roller 8. Here, when the paper feed motor 102 is stopped so that the conveyance distance is longer by Y mm than the distance from the reading entrance sensor 26 to the reading entrance roller 8, the leading edge of the document is placed at the nip portion of the stopped reading entrance roller 8. At the end, the document stops with a certain amount of deflection, and the skew generated when the document is conveyed by the pull-out roller 6 can be corrected. When the paper feed motor is stopped (step S25) and the original is temporarily stopped (resist stop) at the nip portion of the reading entrance roller 8, a resist stop signal is transmitted to the main body control unit 111 via the interface means 107 (step S26). ).

  Subsequently, when a reading start signal is received from the main body control unit 111, the document reading operation shown in FIG. 5 is started. The case where the mode is the single-side mode will be described below. After determining that the mode is the single-sided mode (step S30) and setting the speed of the reading motor 103 from the reading magnification (step S32), the reading motor 103 is driven forward to read the reading inlet roller 8 and the reading outlet roller 10. Driving is performed at a conveyance speed corresponding to the magnification (step S33).

  When the registration sensor 27 detects the leading edge of the document (step S34), the pulse count of the reading motor 103 is started (step S35), and the main controller 111 is sub-scanned at the timing when the leading edge of the document reaches the reading unit. A gate signal indicating the direction effective image area is transmitted (step S38), and the surface gate count is started (step S39). When it is confirmed that the registration sensor 27 is turned off (step S43), counting of the trailing edge of the document is started (step S44), and after counting a predetermined pulse (step S45), the gate count value becomes larger than the document length. When the trailing edge of the original passes through the reading unit (step S46), the gate signal transmission is stopped (step S47).

  When the document that has passed through the reading unit is conveyed by the reading exit roller 10 and the discharge roller 12 (A direction) and discharged to the discharge tray 14, a discharge sensor (not shown) is turned off (step S50), and the discharge is completed. Is transmitted (step S51).

  If the single-side mode is determined in step S31, the reading motor speed is set from the reading magnification (step S54), the reading motor 103 is rotated forward, and counting is started from the tip (step S55). Is equal to the backside predetermined pulse (step S56), and when the correction pulse is equal to the backside predetermined pulse (step S57), DF gate-on is transmitted and gate counting is started (step S59).

  In the case of a double-sided document, the reading exit sensor is turned on when reading the front side (step S60), and the switching claw 15 is turned on by turning on the reverse solenoid 105 (step S61) before the leading edge of the document that has passed through the reading unit reaches the discharge roller 12. Is switched to the position indicated by a two-dot chain line, and is conveyed in the B direction by the discharge roller 12 and the lower driven roller 13 driven by the reading motor 103, and the reverse roller 16 and the driven roller 17 driven by the reverse motor 104. 30 is turned on (step S64).

  When the trailing edge of the document conveyed in the B direction passes through the paper discharge roller 12 (after a predetermined pulse after the reading exit sensor 29 detects the trailing edge of the document), the reverse solenoid 105 is turned off and the switching claw 15 is indicated by a solid line. Then, after a predetermined pulse, the reverse roller 16 is reversely rotated by the reverse rotation drive of the reverse motor 104, and the document is switched back in the C direction. At this time, the driving direction of the reading motor 103 is the same direction and the driving direction of the reversing motor 104 is the reverse direction, and the reversing motor 104 and the reading motor 103 are driven at a high speed in order to shorten the processing time. When the document starts to switch back, the paper feeding motor 102 is reversely rotated (rotated in the direction in which the pull-out roller 6 is driven) at a high speed after a predetermined pulse.

  When the reversing sensor 30 is turned off (step S81), the reversing motor 104 stops (step S82), and the document whose switchback is completed is conveyed in the C direction by the paper discharge roller 12 and the upper driven roller 18, and is the same as on one side. Then, after the pull-out roller 6 and the reading inlet roller 8, the reading inlet roller nip is temporarily stopped for reading the back surface.

  In order to perform skew correction by abutting the leading edge of the document at the reading entrance roller nip even when reading the back side, it is necessary to stop the driving of the reading motor 103 before the leading end of the document reaches the reading entrance roller 8. The reading motor 103 stops driving when the leading edge of the document is detected by the reading entrance sensor 26.

  The document whose registration has been stopped for reading the back side is conveyed to the reading position 28 at a conveyance speed corresponding to the designated magnification after receiving the reading start signal as in the case of reading the front side. When the reading of the back side is completed, the same reversing operation for page alignment is performed again, and the sheet is discharged onto the sheet discharge tray 14 by the sheet discharge roller 13. During the reversing operation for page alignment, it is not necessary to convey at a speed corresponding to the reading magnification. Therefore, the document is allowed to pass through the reading position while being conveyed at high speed, and when the trailing edge of the document is detected by the reading exit sensor 29, the document is decelerated. Prevents popping out during discharge and shortens processing time.

  Next, the main part of the present invention will be described with reference to FIG. As shown in the drawing, a feed inlet lower guide unit 59 is rotatably attached to a stop claw shaft 2a attached to the transport frame 50. As shown in FIG. 1, the vicinity of the stop claw shaft 2a is subjected to an impact when the pickup roller 3 is lowered so as to press the document bundle from above. Therefore, as shown in the drawing, a cushion material 60 is provided on the back side of the sheet feed inlet lower guide unit 59 to reduce the impact. The upper sheet feeding guide unit 51 is provided so as to be openable and closable, so that the upper conveyance path is opened when opened, and the upper conveyance path is closed when closed to eliminate paper jams. Similarly, the lower sheet feed inlet guide unit 59 can open and close the lower conveyance path by rotating about the stop claw shaft 2a.

  Further, as shown in FIG. 11, a cushion roller 61a is provided on the outer periphery of the cushion hub 61 that is rotatable with respect to the stop pawl shaft 2a, and is brought into contact with the cushion material 60 on the back side of the sheet feeding inlet lower guide unit 59. May be. In this configuration, either the cushion material 60 or the cushion roller 61a can be omitted. When the cushion material 60 is omitted, as shown in FIG. 13, the cushion roller 61a abuts against the back side of the sheet feeding inlet lower guide unit 59 to absorb the impact from the pickup roller 3, and the cushion roller 61a is omitted. The cushion hub 61 abuts against the cushion material 60 on the back side of the sheet feeding inlet lower guide unit 59 to absorb the impact from the pickup roller 3.

  Further, the width of the cushion roller 61a and the cushion material 60 is such that the cushion roller 61a or the cushion material 60 does not interfere with the rotation operation of the stop claw shaft 2a by contacting the stop claw shaft 2a. Is shorter.

  Further, as shown in FIG. 12, the stop claw shaft of the cushion hub 61 is provided by providing the claw 62 on the cushion hub 61 and at the same time providing the groove 63 on the stop claw shaft 2a so as to be able to rotate both of them. The position in the axial direction with respect to 2a is determined so as not to deviate from the position where the pickup roller 3 receives an impact.

  As described above, in the present embodiment, the sheet feeding inlet lower guide unit 59 is attached to the structure via a driven shaft such as a paper transport roller and a switching claw passed through the structure. There is no need to provide a shaft, and the structure can be simplified.

  In the present embodiment, since the cushion material 60 is provided on the back side of the area where the pickup roller 3 is in contact with the lower guide unit 59 of the paper feed inlet, the cushion material 60 is not deteriorated by the document conveyance and for a long time. The impact of the pickup roller 3 can be relaxed stably.

  Further, in the present embodiment, a cushion hub 61 that is rotatable with respect to the stop claw shaft 2a to be driven is provided around the stop claw shaft 2a, and the cushion hub 61 is brought into contact with the cushion material 60, or is cushioned. Since the cushion roller 61a is provided on the outer periphery of the hub 61 and is brought into contact with the cushion material 60 on the back side of the sheet feeding inlet lower guide unit, the contact of the cushion material 60 and the cushion roller 61a places a burden on the driving of the stop pawl shaft 2a. Can be prevented.

  Further, in the present embodiment, the width of the cushion material 60 and the cushion roller 61a is smaller than the width of the cushion hub 61. Therefore, the cushion material 60 and the cushion roller 61a protrude and come into contact with the stop claw shaft 2a to stop claw. It is possible to prevent the driving of the shaft 2a from being added.

  Further, in the present embodiment, the cushion hub 61 and the cushion roller 61a that can rotate with respect to the stop claw shaft 2a are axially positioned in the region where the pickup roller 3 abuts by the claw 62 and the groove 63. Further, the impact can be stably reduced without deviating from the range where the pickup roller 3 receives the impact.

  As described above, the automatic document feeder according to the present invention has an effect that it is possible to prevent an impact sound and vibration when the conveyance path is closed, and an image forming apparatus such as a facsimile, a copier, a scanner, or the like. This is useful as an automatic document feeder for feeding a document to the image reading unit.

Sectional drawing which shows the structure of the automatic document feeder of one embodiment of this invention Block diagram of an automatic document feeder according to an embodiment Operation flow diagram of automatic document feeder of one embodiment Operation flow diagram of automatic document feeder of one embodiment Operation flow diagram of automatic document feeder of one embodiment Operation flow diagram of automatic document feeder of one embodiment Operation flow diagram of automatic document feeder of one embodiment Operation flow diagram of automatic document feeder of one embodiment Operation flow diagram of automatic document feeder of one embodiment Sectional drawing which shows the principal part structure of the automatic document feeder of one embodiment of this invention 1 is a perspective view showing a main part configuration of an automatic document feeder according to an embodiment of the present invention. FIG. 1 is an enlarged perspective view showing a main part configuration of an automatic document feeder according to an embodiment of the present invention. 1 is a cross-sectional perspective view showing a main configuration of an automatic document feeder according to an embodiment of the present invention.

Explanation of symbols

1 Document table 2 Stop claw 2a Stop claw shaft (drive shaft)
3 Pickup roller 50 Conveying frame (holding member)
51 Upper sheet feed guide unit 59 Lower sheet feed inlet guide unit 60 Cushion material (first elastic member)
61 Cushion hub (rotating member)
61a Cushion roller (second elastic member)
62 Claw (regulating member)
63 Groove (Regulator)
200 Automatic document feeder

Claims (5)

A paper feed upper guide unit that forms an upper conveyance path of a paper feed unit and is provided to be openable and closable so as to open and close the upper conveyance path;
A pickup roller that is provided in the upper sheet feeding guide unit and that calls the uppermost original of the original bundle in contact with and apart from the original bundle;
An end is arranged close to the pickup roller, forms a lower conveyance path at the entrance of the paper feed unit, and opens and closes with the end as a rotation shaft so as to open and close the lower conveyance path A guide unit provided at the lower end of the paper feed inlet,
A holding member for holding the upper sheet feeding guide unit and the lower sheet feeding guide unit;
The sheet feed inlet lower guide unit is rotatably held by the holding member with a drive shaft provided on the holding member as a rotation shaft,
An automatic document feeder, wherein a first elastic member is provided on a back side of an end portion of the lower guide unit of the paper feed inlet adjacent to the pickup roller.   2. The automatic document feeder according to claim 1, wherein a rotatable member is provided around the drive shaft, and the rotatable member is brought into contact with the first elastic member.   The automatic document feeder according to claim 1, wherein a second elastic member is provided around the rotating member, and the second elastic member is brought into contact with the first elastic member.   3. The axial width of the drive shaft of the first elastic member and the second elastic member is smaller than the axial width of the drive shaft of the rotating member. Item 4. The automatic document feeder according to Item 3.   5. The automatic document feeder according to claim 2, further comprising a regulating member that regulates a position of the rotating member in an axial direction of the drive shaft.

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