JP5245776B2 - Automatic document feeder and image forming apparatus - Google Patents

Description

  The present invention relates to an automatic document feeder and an image forming apparatus that convey stacked documents one by one to a reading position.

  It is well known that a scanner for reading document information is mounted in an image forming apparatus such as a copying machine, a facsimile machine, a printer, or a multifunction machine having at least two functions. It is also known to provide an automatic document feeder that conveys documents stacked on the scanner one by one to the reading position.

In this type of automatic document feeder, a device that automatically conveys a double-sided document loaded on a document table and reads information on both sides is also known, and is described in Patent Document 1 and the like.
FIG. 8 is a schematic configuration diagram showing an automatic document feeder capable of reading the double-sided document.

  In FIG. 8, reference numeral 1 denotes an automatic document feeder, which is attached to an upper portion of an image reading apparatus 2 such as a copying machine, a facsimile, a scanner or the like so as to be opened and closed. The image reading device 2 is provided with a slit glass (reading position) 3 and a contact glass 4 on its upper surface, and the automatic document feeder 1 transports the document and passes it over the slit glass 3 or the contact glass 4. The document is read by setting the document on top. Further, a single-side mode and a double-side mode can be set by an instruction from an operation unit (not shown) of the image reading apparatus 2, and the operation of the automatic document feeder 1 is controlled according to the set mode.

  Next, the automatic document feeder 1 will be described. Reference numeral 5 denotes a document placement table on which the document 6 is placed and set. The document 6 is set in page order with the image surface to be read facing up. Reference numeral 7 denotes a calling roller that feeds the document 6 to a separation unit downstream of the document conveyance. Usually, the document 6 is located at a standby position at a predetermined interval from the document stacking table 5 and the document 6 is on the document mounting table 5. When the document is detected by the placement sensor 8 and the start of feeding of the document is instructed, the document is controlled to move down from the standby position to a position in contact with the upper surface of the document 6.

  Further, 9 is a paper feed roller that rotates in the clockwise direction to feed the original 6 on the original table 5. Reference numeral 10 denotes a blocking roller as a blocking member. By stopping or rotating clockwise, the uppermost document 6 is caused by the mutual frictional action among the documents 6 called by the calling roller 7 with the sheet feeding roller 9. Separate one by one. Although FIG. 1 illustrates the configuration using the blocking roller 10 as the blocking member, the blocking member may be a separation pad having a surface that causes friction with the document instead of the blocking roller 10. The separation effect can be obtained. The calling roller 7, the paper feed roller 9, and the blocking member constitute a separation paper feeding unit.

  (A) is a first conveyance path, which is formed between the guides 11 and 11a, and is a path for moving the document 6 separated and conveyed by the sheet feeding roller 9 of the separation unit onto the slit glass 3. is there. The first transport path (A) is provided in an arch shape between the separation unit and the slit glass 3 serving as a document reading unit, and reverses the document 6 sent out by the sheet feed roller 9 to form the slit glass. Lead 3 up.

  (B) is a paper discharge path formed between the guides 12 and 12a, and the original 6 conveyed through the slit glass 3 from the first conveyance path (A) to the original paper discharge port 13 is shown. It is a passage for moving. Reference numeral 14 denotes a document discharge table on which the document 6 discharged from the document discharge port 13 is stacked, and is provided below the document placement table 5 and above the contact glass 4. A pressing means 15 made of an elastic member such as sponge or rubber is provided on the surface facing the contact glass 4 below the document discharge table 14, and the pressing means 15 is placed at a predetermined reading position on the contact glass 4. The set original is pressed to prevent the original from floating from the contact glass 4.

  (C) is a switchback conveyance path, which is formed between the guide 16 and the guide 16a, and between the guide 16a and the switching claw 17 provided below the document placing table 5 and above the document discharge table 14. This is a path for switching back the document 6 conveyed from the document discharge port 13 of the discharge path (b) and guiding it again to the first transfer path (b). Is provided above the document discharge table 14.

  The switching claw 17 is provided above the document discharge table 14, and the document 6 discharged from the document discharge port 13 at the end of the discharge path (B) is switched to the document discharge by switching to the dotted line position. When the document 6 is guided to the switchback conveyance path (c) without being loaded on the table 14 and then introduced into the switchback conveyance path (c), the original 6 is switched to the solid line position, thereby being switched to the switchback conveyance path (c). This is for guiding the switched-back document 6 from the rear end to the second transport path (d). The switching claw 17 constitutes first switching means.

  (D) is a second conveyance path, which is formed between the guides 18 and 18a, and merges with the first conveyance path (A) and is switched back by the switchback conveyance path (C). 6 is a path for moving 6 to the first transport path (A). In addition, 19, 19a, 20, 20a, 21, 21a, 22, and 22a are feed roller pairs, and the roller pairs 19, 19a, 20, and 20a are fed from the paper feed roller 9 in the first transport path (A). The document 6 is conveyed to the slit glass 3. Further, the roller pairs 21 and 21 a convey the document 6 that has passed over the slit glass 3 in the sheet discharge path (b) to the document discharge port 13. The roller pairs 22 and 22a convey the document 6 to the first conveyance path (b) in the second conveyance path (d).

  Further, reference numerals 23, 24, and 25 denote sheet feed rollers, which are provided in the vicinity of the document discharge port 13. The document 6 passing through the discharge path (b) between the rollers 23 and 24 is transferred to the document discharge table 14 or the switch. Transport to the back transport path (c). Further, the document 6 switched back by the switchback conveyance path (C) between the rollers 24 and 25 is conveyed from the switchback conveyance path (C) to the second conveyance path (D).

  Further, 26 and 26a are forward and reverse feed roller pairs (switchback members), and the feed roller pairs 26 and 26a are provided on the switchback transport path (c) and into the switchback transport path (c). The conveyed document 6 is introduced into the switchback conveyance path (c), and then reversely rotated to switch back the document 6 from the paper discharge path (b) and conveyed to the second conveyance path (d).

  Reference numeral 27 denotes an inlet portion of the first conveyance path (A) between the sheet feeding roller 9 and the blocking roller 10 and the roller pair 19 and 19a of the separation unit, that is, the vicinity of the so-called downstream of the document conveying direction from the sheet feeding roller 9. The transmissive sensor 28 is a transmissive sensor disposed near the upstream side in the document conveying direction from the so-called slit glass 3, the exit portion of the first conveying path (A) between the roller pair 20, 20 a and the slit glass 3. , 29 is a transmission type sensor disposed in the paper discharge path (b) between the roller pair 21, 21a and the roller 23, 24, and 30 is a roller 23, 24, 25 and the roller pair 26, 26a. It is a transmission type sensor disposed between them. Sensors 27, 28, 29, and 30 detect the leading edge or trailing edge of the document 6 that passes through the position.

Next, the operation will be described.
A. When the single-sided mode is set When a start key provided in an operation unit (not shown) of the image reading device 2 is pressed, a document is set on the document placing table 5 by a detection signal from the document placing sensor 8. Is checked, and if a document is set on the document table 5, document feeding operation is started. First, the calling roller 7 and the paper feeding roller 9 are driven, and the calling roller 7 is lowered to send the document 6 to the separation unit. Then, the separation unit sequentially separates the sheets on the document 6 set on the document table 5 and feeds them to the first transport path (A).

  Next, when the leading edge of the original 6 is detected by the sensor 28, the reading start timing of the original 6 is taken, and the original 6 is read. When the passage of the trailing edge of the document 6 is detected by the sensor 29 and a predetermined time T2 has elapsed, the document 6 is discharged from the document discharge port 13 and stacked on the document discharge table 14 with the image side down. The

When the passage of the rear end of the document 6 is detected by the sensor 28, when the document placement sensor 8 detects the document 6, the feeding operation of the second document 6 is started. Thereafter, the document 6 is repeatedly subjected to the above-described operation until the document placement sensor 8 no longer detects the document 6, thereby completing the single-sided document processing for the document 6 on the document placement table 5.
B. When duplex mode is set

The same operation as in the case where the single-side mode is set is performed until the start key provided in the operation unit (not shown) of the image reading apparatus 2 is pressed and the leading edge of the first original is detected by the sensor 28. When the leading edge of the document 6 is detected by the sensor 28, the driving of the roller pairs 21, 21a and the rollers 23, 24, 25 and the forward rotation driving of the roller pairs 26, 26a are started by the signal. Further, the reading start timing of the document 6 is taken by the signal, and the surface of the document 6 is read.
When the passage of the rear end of the document 6 is detected by the sensor 28, the driving of the roller pair 19, 19a is stopped.

  Next, when the passage of the rear end of the document 6 is detected by the sensor 29, the switching claw 17 is switched from the solid line position to the dotted line position. Further, when the passage of the rear end of the document 6 is detected by the sensor 30, the switching claw 17 is switched from the dotted line position to the solid line position, and the rotation directions of the roller pairs 26 and 26a are switched. If the sensor 29 is not provided, the switching claw 17 is switched from the dotted line position to the solid line position after the passage of the sensor 28 at the trailing edge of the document 6 and a predetermined time Ta has elapsed, and the rotation of the roller pairs 26 and 26a. The direction can be switched.

Due to the reverse rotation of the roller pairs 26 and 26a, the document 6 is conveyed in a switchback manner and enters the second conveyance path (d) from the rear end.
Next, the document 6 that has entered the second transport path (d) is fed into the first transport path (b). Then, when the leading edge of the document 6 is detected by the sensor 28, the reading operation and the switchback conveyance operation of the back surface of the document 6 are performed similarly to the front surface, and the document is again sent to the first conveyance path (A). The document 6 is again fed into the first conveyance path (A), and the document 6 is not read even if the sensor 28 detects the leading edge of the document 6 again.

  Next, even if the leading edge of the document 6 is detected by the sensor 29, the switching claw 17 is not operated, and the passage of the trailing edge of the document 6 is detected by the sensor 29 and the document 6 is discharged after a predetermined time T2. The paper is discharged from the paper mouth 13 and stacked on the document discharge table 14 with the image surface of the front side facing down.

  Further, when the document passing sensor 8 detects the document 6 at the time when the third passage of the trailing edge of the document 6 is detected by the sensor 28, the feeding operation of the second document 6 is started. The Thereafter, the document 6 is repeatedly subjected to the above-described operation until the document placement sensor 8 no longer detects the document 6, thereby completing the double-sided document processing for the document 6 on the document placement table 5.

  In the automatic document feeder 1 configured as described above, at least the separation paper feeding unit and the feed roller pair 19, 19a, the feed roller pair 20, 20a, the feed roller pair 21, 21a, the roller 24, and the feed roller pair 22, 22a It is driven by one drive motor. In such a configuration, if the separation sheet feeding unit operates during conveyance in the second conveyance path (d), there is a problem that the next document is fed. Therefore, the conventional automatic document conveyance device 1 has a drive motor and separation sheet feeding. An electromagnetic clutch that turns driving on and off is provided between the sections.

  However, if an electromagnetic clutch is used, the area occupied by the drive transmission unit is large, and the device protrudes in the height direction and depth direction of the device, and the cover for covering it also becomes large, preventing space down and cost increase accordingly. There was a problem of becoming.

JP-A-9-166896

  In view of the above-described conventional circumstances, the present invention can turn on / off the driving of the separation sheet feeding unit without using an electromagnetic clutch, and can perform drive transmission with reliability, and an image forming apparatus. An object is to provide an apparatus.

In order to solve the above-described problems, the present invention drives a separation sheet feeding unit that separates a plurality of documents placed on a document placing table one by one and feeds them to a reading position, and drives the separation sheet feeding unit. In an automatic document feeder having a driving motor and intermittent means for selectively interrupting driving of the separation paper feeding unit by the driving motor, the intermittent means can mesh with an output gear driven by the drive motor A swinging gear provided on the swinging gear, a swinging arm that holds the swinging gear so as to be swingable, a connection position for engaging the swinging gear with the output gear via the swinging arm, and a separation position that is separated from the output gear. And a solenoid that operates the regulating member, the regulating member restricts movement of the swing gear in a direction away from the output gear, and the swing arm is Oscillating gear is the output gear While restricting the movement in the direction brute, rocking fulcrum at one end to the swing arm, swing supporting shaft is provided for supporting the swing gear on the other end, the regulating member is swing support shaft The present invention proposes an automatic document feeder characterized by swinging a swinging gear via a pin .

  According to the present invention, it is advantageous that the restricting member is provided with a constraining abutting surface that is in contact with the swing support shaft and restricts movement of the swing gear in a direction away from the output gear.

Still further, according to the present invention, it is advantageous to restrict the swinging gear from approaching the output gear by the end of the other end of the swinging arm coming into contact with the shaft of the output gear.
Furthermore, in the present invention, it is advantageous that the other end side end portion of the swing arm is formed on a curved surface concentric with the pitch circle of the swing gear.

In order to solve the above problems, the present invention proposes an image forming apparatus characterized in that the automatic document feeder according to any one of claims 1 to 4 is attached.

  According to the present invention, the drive to the separation paper feeding unit can be interrupted without using an electromagnetic clutch, so that the cost is low and the space is saved, and the rotation failure is caused by the force applied to the swing gear during transmission. Thus, reliable drive transmission can be obtained.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a perspective view showing an internal structure of an automatic document feeder according to an embodiment of the present invention. In the members such as the calling roller 7 and the paper feeding roller 9 described in FIG. Is attached.

  In FIG. 1, reference numeral 100 denotes a drive motor that drives the separation paper feeding unit 200, and an output gear 101 shown in FIGS. 2 and 3 is provided on the output shaft of the drive motor 100. FIG. 2 is an explanatory view showing a gear train from the output gear 101 to the drive gear 106 of the separation paper feeding unit 200, FIG. 3 is a perspective view of FIG. Engage. The swinging gear 102 meshes with the reduction large-diameter gear 104 via the idler gear 103, and the reduction small-diameter gear 105 provided coaxially with the reduction large-diameter gear 104 meshes with the drive gear 106 described above. When the drive gear 106 rotates, the paper feed roller 9 is driven via the drive shaft 110, and the pickup roller 7 that is drivingly connected thereto also descends while rotating. Then, as shown in FIG. 8, the document 6 set on the document table 5 is sent out, and only the uppermost sheet of the sent document 6 is sent out to the first transport path (A) by the paper feed roller 9 and the blocking member 10. It is.

  The drive motor 100 that drives the separation sheet feeding unit 200 drives the roller 24 to drive the feed roller pair 19, 19a, the feed roller pair 20, 20a, the feed roller pair 21, 21a, the roller 24, and the feed roller pair 22, 22a. In addition, when the pair of feed rollers 22 and 22a is driven and the document is transported through the second transport path (d), the separation paper feeding unit 200 must be stopped. For this reason, in the present embodiment, an intermittent means for turning on / off the drive to the separation sheet feeding unit 200 is provided between the drive motor 100 and the separation sheet feeding unit 200.

  The interrupting means of the present embodiment is configured such that the drive of the drive motor 100 is interrupted with respect to the separation paper feeding unit 200 when the swinging gear 102 described above contacts and separates from the output gear 101. In this case, the oscillating gear 102 rotates on the oscillating support shaft 112 provided at the other end of the oscillating arm 120 that is rotatably attached to the shaft 114 of the reduction gears 104 and 105 at one end. The swing support shaft 112 is inserted into the restriction member 122 so that the swing of the swing arm 120 is restricted by the restriction member 122 shown in FIG.

  1 and 4 (a) and 4 (b), the restricting member 122 is formed in an elongated rectangular frame shape, and the elongated hole 122a extending in the left-right direction is formed on both sides in the longitudinal direction, the left-right direction shown in FIG. , 122b are formed. By inserting guide pins 124 and 125 provided on the motor bracket 123 shown in FIG. 1 into the long holes 122a and 122b, the regulating member 122 moves in the left-right direction, which is the extending direction of the long holes 122a and 122b. It is possible. The restricting member 122 is provided with a constraining abutment surface 126 for restricting the swing arm 120 via the swing support shaft 112 and a separation contact surface 127.

  The regulating member 122 thus formed has a solenoid 121 connected to one end in the longitudinal direction, and a tension spring 128 that constantly biases the rightward movement force of FIG. It has been. When the solenoid 121 is demagnetized, the regulating member 122 is moved to the right by the tension spring 128 as shown in FIG. 4A, and the guide pin 125 comes into contact with the left end of the long hole 122b and stops. At this time, as shown in FIGS. 4A and 5A, the swing support shaft 112 is regulated by the restraining abutment surface 126 so that the swing gear 102 is engaged with the output gear 101, and the guide pin 124 is It is not in contact with the left end of the long hole 122a, but is located on the right side of it.

  On the other hand, when the solenoid 121 is excited, the regulating member 122 is moved to the left against the action of the tension spring 128 as shown in FIG. 4B, and the guide pin 124 is moved to the right end of the long hole 122a. Stops in contact. At this time, the swing support shaft 112 is regulated by the inclined separation contact surface 127, and the swing gear 102 is separated from the output gear 101 as shown in FIGS. 4B and 5B, and the drive motor 100. Even if is driven, the separation sheet feeding unit 200 does not operate. That is, since the swinging gear 102 is pushed upward to the left and separated from the output gear 101, the separation paper feeding unit 200 does not operate. When the solenoid 121 is on, the guide pin 125 does not come into contact with the right end of the long hole 122b and is located on the left side. In addition, since the point of application of the regulating member 122 to the swing arm 120 is the swing support shaft 112 closest to the swing gear 102, the stacking tolerance between the swing gear 102 and the shaft of the output gear 101 is increased. It is decreasing.

  Further, the guide pin 124 that is a member that restricts the operating direction of the restricting member 122 can be used as the rotating shaft 114 of the swing arm 120. If comprised in this way, the stacking tolerance between the axis | shafts of the rocking | fluctuation gear 102 and the output gear 101 can be reduced.

  Furthermore, the guide pin 125 that is a member that restricts the operating direction of the restricting member 122 can be used as the shaft 111 of the output gear 101. If comprised in this way, the stacking tolerance between the axis | shafts of the rocking | fluctuation gear 102 and the output gear 101 can be reduced.

  By the way, since the regulating member 122 and the solenoid 121 are connected to the elongated hole 122c extending in the direction orthogonal to the operating direction of the regulating member 122 via the pin 121a, the tilt of the solenoid 121 is shifted and the operating direction of the regulating member 122 is Even if it deviates, the movement remains smooth.

  The intermittent means configured as described above can intermittently drive the separation paper feeding unit 200 by turning on and off the solenoid 121 without using an electromagnetic clutch as in the prior art. Therefore, when the electromagnetic clutch SC is used as shown by the dotted line in FIG. 6, the thickness in the depth direction in the transmission path can be reduced, and the electromagnetic clutch SC is separated and supplied as shown by the dotted line in FIG. It was possible to reduce the height by not being disposed on the paper portion 200 axis. Further, the cost for the electromagnetic clutch SC could be reduced to the cost for the solenoid 121.

  By the way, when the drive of the separation paper feeding unit 200 is transmitted by meshing of the rocking gear 102 and the output gear 101, the rocking gear 102 that can be rocked by the pressure angle generated when the gear meshes is output. If a force to bite into the gear 101 is applied, rotation failure may occur due to the bottom contact of the gear teeth.

  Therefore, the tip 120a of the swing arm 120 is rounded so as to be concentric with the pitch circle of the swing gear 102, and when the swing gear 102 and the output gear 101 are engaged, the tip 120a of the swing arm 120 is the axis of the output gear 101. The tip 120a of the oscillating arm 120 hits the shaft 111 of the output gear 101 to prevent further digging when it tries to bite into the oscillating gear 102 and the output gear 101 by touching or very close to 111. Can do. At this time, if the tip 120a of the swing arm 120 is formed in a round shape that is concentric with the pitch circle of the swing gear 102, the tip 120a of the swing arm 120 smoothly touches the shaft 111 of the output gear 101, The load applied to the rotation of the output gear 101 by the swing arm 120 can also be reduced.

  In addition, when the output gear 101 rotates in the reverse direction and the swing gear 102 is forced to escape from the output gear 101, the tooth tip is prevented from escaping by the swing support shaft 112 hitting the restraining abutment surface 126. Is done. The reverse rotation of the output gear 101 is performed when the pickup roller 7 lowered toward the original surface is returned to the original position.

  In the present embodiment configured as described above, the driving of the separation sheet feeding unit 200 can be interrupted without using an electromagnetic clutch, and rotation failure due to the force applied to the swinging gear 102 during transmission can be prevented. Thus, reliable drive transmission can be obtained.

1 is a perspective view showing an internal structure of an automatic document feeder according to the present invention. It is explanatory drawing which shows the gear train from the output gear of FIG. 1 to the drive gear of a separation paper feeding part. FIG. 3 is a perspective view of the gear train of FIG. 2 as viewed from the rear side. (A) is explanatory drawing which shows the regulating member at the time of gear connection, (b) is explanatory drawing which shows the regulating member at the time of gear separation. (A) is explanatory drawing which shows the gear train at the time of gear connection, (b) is explanatory drawing which shows the gear train at the time of gear separation. FIG. 2 is an explanatory plan view when it is assumed that an electromagnetic clutch is provided in the automatic document feeder shown in FIG. 1. FIG. 3 is an explanatory side view when it is assumed that the automatic document feeder shown in FIG. 1 is provided with an electromagnetic clutch. FIG. 10 is a schematic explanatory view showing a conventional automatic document feeder.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 Drive motor 101 Output gear 102 Oscillating gear 106 Driving gear 112 Oscillating support shaft 120 Oscillating arm 120a End of the oscillating arm 121 Solenoid 122 Restricting member 126 Constraint abutting surface 200 Separating paper feeding unit

Claims (5)

A separation sheet feeding unit that separates a plurality of documents placed on the document table one by one and feeds them to a reading position; a drive motor that drives the separation sheet feeding unit; and the separation feeding by the drive motor In an automatic document feeder having an intermittent means for selectively interrupting driving to a paper section,
The intermittent means is
A swing gear provided so as to be able to mesh with an output gear driven by the drive motor;
A swing arm for swingably holding the swing gear;
A regulating member that oscillates between a connection position where the oscillating gear meshes with the output gear via the oscillating arm and a separated position away from the output gear;
A solenoid for operating the regulating member;
The restricting member restricts movement of the swing gear in a direction away from the output gear, and the swing arm restricts movement of the swing gear in a direction approaching the output gear ;
The swing arm is provided with a swing support shaft at one end and a swing support shaft for supporting the swing gear at the other end, and the regulating member swings the swing gear through the swing support shaft. An automatic document feeder characterized by that. 2. The automatic document feeder according to claim 1 , wherein the restricting member is provided with a constraining abutting surface that is in contact with the swing support shaft and restricts movement of the swing gear in a direction away from the output gear. An automatic document feeder characterized by comprising: 2. The automatic document feeder according to claim 1 , wherein the other end of the swing arm is in contact with the shaft of the output gear, thereby restricting the swing gear from approaching the output gear. A feature of the automatic document feeder. 4. The automatic document feeder according to claim 3 , wherein the other end of the swing arm is formed on a curved surface concentric with the pitch circle of the swing gear. . An image forming apparatus, comprising the automatic document feeder according to claim 1 .

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