JP2024064095A - Document Feeder - Google Patents

Abstract

[Problem] To provide a document transport device capable of appropriately driving a feed roller without using a clutch. [Solution] The document transport device includes an actuator 47 on which a document is placed and rotates, a feed roller 45, a feed roller 43 rotatably supported on a rotating shaft 51 and rotates by receiving the rotational force of the rotating shaft 51 to transport the document sent out and form a separation nip, a slider 59 movable along the rotating shaft 51 between a connecting position connecting the feed roller 43 and the rotating shaft 51 and a separated position separated from the feed roller 43, and an operating lever 61 supporting the slider 59 and moving in a direction parallel to the axial direction of the rotating shaft 51 by the rotation of the actuator 47. When the actuator 47 is not rotating, the operating lever 61 moves the slider 59 to the separated position, and when the actuator 47 rotates, the operating lever 61 moves the slider 59 to the connecting position. [Selected Figure] Figure 2

Description

The present invention relates to a document transport device that transports documents one by one from a stack of documents.

The document transport device is equipped with a document tray on which a stack of documents is placed, a feed roller that contacts the top document in the stack and rotates to feed the document, and a paper feed roller that transports the fed document to the transport path. The paper feed roller contacts a pad to form a separation nip between the two. The fed documents are separated by the separation nip and transported one by one to the transport path.

The paper transport device described in Patent Document 1 is equipped with an electromagnetic clutch that switches between a transmission state in which the driving force from the drive source is transmitted to a separation roller (corresponding to a paper feed roller) and a non-transmission state in which the driving force is not transmitted to the separation roller. By switching the electromagnetic clutch, it is possible to rotate the separation roller at a predetermined timing.

JP 2020-147428 A

However, since providing an electromagnetic clutch as described in Patent Document 1 increases costs, a configuration that does not include an electromagnetic clutch is desirable for low-cost models. However, if an electromagnetic clutch is not provided, the rotation of the separation roller cannot be properly controlled, and friction between the separation roller and the pad may occur, causing wear on both, and making it impossible to transport documents correctly.

The present invention takes the above circumstances into consideration and aims to provide a document transport device that can properly drive the paper feed roller without using a clutch.

In order to solve the above problem, the document transport device of the present invention includes an actuator that rotates when a document is placed on a document tray, a feed roller that feeds out the document, a paper feed roller that is rotatably supported on a rotating shaft that is driven to rotate and that rotates by receiving the rotational force of the rotating shaft to transport the document fed out by the feed roller and contacts a separating member to form a separation nip, a connection position that connects the paper feed roller and the rotating shaft to transmit the rotational force to the paper feed roller, and a connection position that is separated from the paper feed roller to transmit the rotational force from the rotating shaft to the paper feed roller. The device is equipped with a slider that is supported movably along the rotation shaft between a separation position where the transmission of rotational force is blocked and a slider that is supported movably along the rotation shaft, and an operation lever that rotatably supports the slider and moves in a direction parallel to the axial direction of the rotation shaft by the rotation of the actuator. When the document is not placed on the document tray and the actuator is not rotating, the operation lever moves the slider to the separation position, and when the document is placed on the document tray and the actuator rotates, the operation lever moves to move the slider to the connected position.

The document transport device of the present invention may further include a link lever provided between the actuator and the operating lever for converting the rotational motion of the actuator into a reciprocating motion along a direction parallel to the axial direction of the rotation shaft of the operating lever.

The document transport device of the present invention may further include a transmission gear fixed to the rotating shaft, and a coupling between the transmission gear and the slider that is movable along the rotating shaft and can rotate integrally with the transmission gear, and in the coupling position, the slider is coupled to the coupling and also to the paper feed roller.

The document transport device of the present invention may be characterized in that, at the connection position, the feed roller and the slider are connected by a ratchet mechanism.

According to the present invention, the use of a slider allows the feed roller to rotate properly without using an electromagnetic clutch.

1 is a front view showing a schematic internal structure of a document transport device according to an embodiment of the present invention; 1 is a perspective view showing a paper feed unit of a document transport device according to an embodiment of the present invention; 4 is a perspective view showing a connection mechanism between a feed roller and a transmission gear in the document transport device according to the embodiment of the present invention; FIG. 4 is a perspective view showing a connection mechanism between a feed roller and a transmission gear in the document transport device according to the embodiment of the present invention; FIG. 4 is a perspective view showing a connection mechanism between a feed roller and a transmission gear in the document transport device according to the embodiment of the present invention; FIG. 4 is a cross-sectional view showing a slider and an operating lever in a document transport device according to an embodiment of the present invention; 3 is a perspective view showing each end of an operating lever and a link lever in the document transport device according to the embodiment of the present invention; FIG. 4 is a perspective view showing a connection portion between an operating lever and a link lever in the document transport device according to the embodiment of the present invention; FIG. 4 is a perspective view showing a connection portion between an operating lever and a link lever in the document transport device according to the embodiment of the present invention; FIG. 2 is a perspective view showing an operating lever, a link lever, and an actuator in the document transport device according to the embodiment of the present invention; FIG. 1 is a front view of an actuator, a link lever, and an operating lever in a document transport device according to an embodiment of the present invention when no document stack is placed on a paper feed tray; 1 is a front view of an actuator, a link lever, and an operating lever in a state in which a stack of documents is placed on a paper feed tray in a document transport device according to an embodiment of the present invention. FIG. 1 is a front view of a paper feed unit in a paper transport device according to an embodiment of the present invention when no document stack is placed on a paper feed tray; 1 is a diagram showing a paper feed unit viewed from the left side in a state in which no document stack is placed on a paper feed tray in a document transport device according to an embodiment of the present invention. 1 is a front view of a paper feed unit when feeding a document in a document transport device according to an embodiment of the present invention; FIG. 1 is a diagram showing a paper feed unit when feeding a document in a document transport device according to an embodiment of the present invention, as viewed from the left side. 1 is a front view of a paper feed unit in a document transport device according to an embodiment of the present invention, showing a state in which a document passes through a separation nip. 1 is a diagram showing a paper feed unit as viewed from the left side in a state in which a document passes through a separation nip in a document transport device according to an embodiment of the present invention. 1 is a front view of a paper feed unit in a document transport device according to an embodiment of the present invention, in a state in which the last document is transported by a first transport roller pair; FIG. 11 is a diagram of the paper feed unit viewed from the left side in a state in which the last document is transported by a first transport roller pair in the document transport device according to the embodiment of the present invention. FIG. 1 is a perspective view showing a connection mechanism between a feed roller and a transmission gear in a state in which the last document is transported by a first transport roller pair in a document transport device according to an embodiment of the present invention; FIG. 1 is a perspective view showing a connection mechanism between a feed roller and a transmission gear in a state in which the last document is transported by a first transport roller pair in a document transport device according to an embodiment of the present invention; FIG.

Below, we will explain a document transport device according to one embodiment of the present invention with reference to the drawings.

First, the overall configuration of the document transport device 1 according to this embodiment will be described with reference to FIG. 1. FIG. 1 is a cross-sectional view that shows a schematic internal structure of the document transport device 1. In the following description, the front side of the paper in FIG. 1 is the front side (front side) of the document transport device 1. Fr, Rr, L, and R in each figure indicate the front side, rear side, left side, and right side, respectively, of the document transport device.

The document transport device 1 is placed, for example, on the top surface of the document reading device 3. The document transport device 1 automatically transports the document and reads an image on one side of the transported document. The document reading device 3 reads an image on the other side of the document transported by the document transport device 1. The read image is formed on paper, for example, by an image forming device (not shown).

The document transport device 1 includes a transport section 5 that reads images while transporting the document, a document tray 7 on which the document whose image is to be read by the transport section 5 is placed, and a discharge tray 9 on which the document whose image has been read by the transport section 5 is stacked.

A paper feed opening 11 and a discharge opening 13 are formed on the right side of the transport section 5. The discharge opening 13 is formed below the paper feed opening 11. A U-shaped transport path 15 is formed between the paper feed opening 11 and the discharge opening 13 and faces horizontally when viewed from the front. The direction in which the document is transported along the transport path 15 from the paper feed opening 11 to the discharge opening 13 is defined as the document transport direction.

In the transport path 15, a paper feed unit 17, a first transport roller pair 19, a second transport roller pair 21, a reading unit 23, and a discharge roller 25 are provided in this order from the upstream side in the transport direction. The paper feed unit 17 is provided at the paper feed opening 11, and the discharge roller 25 is provided at the discharge opening 13. The paper feed unit 17 will be described later.

Next, the document transport operation will be briefly described. When a stack of documents is placed on the document tray 7, the top document of the document stack is sent from the paper feed opening 11 to the transport path 15 by the paper feed unit 17. The sent document is transported along the transport path 15 by the first transport roller pair 19 and the second transport roller pair 21. When the document is transported to the reading unit 23, an image on one side of the document is read by the reading unit 23. The document is then discharged from the discharge opening 13 by the discharge rollers 25 and loaded onto the discharge tray 9.

Next, the paper feed section 17 will be described with reference to FIG. 2. FIG. 2 is a perspective view showing the paper feed section 17 (paper feed unit 31). The paper feed section 17 includes the paper feed unit 31 and a separation pad 33 (see FIG. 1). The separation pad 33 is an example of a separation member of the present invention.

First, the paper feed unit 31 will be described. As shown in FIG. 2, the paper feed unit 31 is supported by a paper feed holder 41 and includes a paper feed roller 43 and a feed roller 45 that feed a document from a document stack, and an actuator 47 that is driven by the document stack.

The paper feed holder 41 is a rectangular box-shaped member with an open bottom, and has a pair of side panels and a top panel. The paper feed holder 41 is rotatably supported on the free end of a rotating shaft 51 that is cantilevered on the rear side panel of the transport unit 5. A drive gear 53 is fixed to the fixed end of the rotating shaft 51. The drive gear 53 is connected to the output gear of a motor (not shown) via a gear train (not shown). The motor can rotate in both directions. When a document is fed out, the rotating shaft 51 is driven by the motor and rotates in the clockwise direction in FIG. 2.

The free end of the rotating shaft 51 penetrates the downstream end of a pair of side plates of the paper feed holder 41 in the transport direction. This allows the paper feed holder 41 to rotate up and down around the rotating shaft 51. A torque limiter (not shown) is provided between one side plate of the paper feed holder 41 and the rotating shaft 51. When the torque applied from the rotating shaft 51 to the side plate, i.e., the paper feed holder 41, is equal to or less than a threshold value, the torque limiter rotates the paper feed holder 41 together with the rotating shaft 51. On the other hand, when the torque applied to the paper feed holder 41 reaches the threshold value, the rotating shaft 51 is rotated idly relative to the paper feed holder.

Next, the paper feed roller 43 will be described. The paper feed roller 43 is rotatably supported on the free end of the rotating shaft 51 between a pair of side plates of the paper feed holder 41. The paper feed roller 43 and the rotating shaft 51 can be connected by a connecting mechanism. That is, when the two are connected by the connecting mechanism, the rotational force of the rotating shaft 51 can be transmitted to the paper feed roller 43, and when the two are separated by the connecting mechanism, the transmission of the rotational force of the rotating shaft 51 to the paper feed roller 43 is blocked.

The coupling mechanism between the feed roller 43 and the rotating shaft 51 will be described with reference to Figures 3A, 3B, and 3C. Figures 3A, 3B, and 3C are perspective views showing the coupling mechanism between the feed roller 43 and the rotating shaft 51. In the following description, the axial direction refers to the axial direction of the rotating shaft 51.

The front end surface of the paper feed roller 43 is provided with multiple protrusions 43a that protrude in the axial direction and are spaced at predetermined intervals in the circumferential direction.

A transmission gear 55 is fixed to the free end of the rotating shaft 51. In this way, the transmission gear 55 rotates together with the rotating shaft 51. The transmission gear 55 is disposed forward of the paper feed roller 43. A protrusion 55a that protrudes in the axial direction is formed on the rear end surface of the transmission gear 55.

The coupling mechanism includes a coupling 57 rotatably supported on the rotating shaft 51 and a slider 59 between the transmission gear 55 and the paper feed roller 43. The coupling 57 is disposed on the side of the transmission gear 55, and the slider 59 is disposed on the side of the paper feed roller 43.

The coupling 57 has a cylindrical portion 57a through which the rotating shaft 51 is inserted, a protrusion 57b that protrudes in the axial direction from a front end surface 57d of the cylindrical portion 57a, and ratchet teeth 57c provided on the rear end surface of the cylindrical portion 57a. The front end surface 57d of the cylindrical portion 57a is inclined along the circumferential direction. In detail, as shown in FIG. 3B, the front end surface 57d is inclined forward (towards the transmission gear 55) from the upstream side to the downstream side in the rotation direction of the rotating shaft 51 when the document is fed (see the arrow in the figure). The ratchet teeth 57c have a first surface along the axial direction and a second surface inclined so as to intersect with the axial direction.

In a state where the rear end surface of the projection 55a of the transmission gear 55 is in contact with the front end surface 57d of the coupling 57 (see FIG. 3A), when the rotating shaft 51 (transmission gear 55) rotates in the rotational direction and the rear end surface of the projection 55a moves along the inclined front end surface 57d of the coupling 57, the coupling 57 is pushed in and moves backward, that is, along the rotating shaft 51 toward the slider 59. Then, as shown in FIG. 3B, when the side surface of the projection 55a of the transmission gear 55 abuts against the side surface of the projection 57b of the coupling 57, the projection 57b of the coupling 57 is pushed by the projection 55a of the transmission gear 55, and the coupling 57 rotates together with the transmission gear 55. The coupling 57 can move along the axial direction within a range where the projection 57b and the projection 55a of the transmission gear 55 overlap in the axial direction. That is, the coupling 57 can rotate together with the transmission gear 55, can rotate relative to the rotating shaft 51 within a predetermined range in the circumferential direction, and can move relative to the rotating shaft 51 within a predetermined range in the axial direction.

The slider 59 has a cylindrical portion 59a through which the rotating shaft 51 is inserted, ratchet teeth 59b provided on the front end surface of the cylindrical portion 59a, and a number of protrusions 59c protruding in the axial direction from the rear end surface of the cylindrical portion 59a. The ratchet teeth 59b have a first surface along the axial direction and a second surface inclined so as to intersect with the axial direction, and can mesh with the ratchet teeth 57c of the coupling 57.

When the ratchet teeth 59b of the slider 59 mesh with the ratchet teeth 57c of the coupling 57 (see Figures 3A and 3B), the slider 59 can rotate together with the coupling 57. Also, when the protrusions 59c of the slider 59 enter between the protrusions 43a of the paper feed roller 43 (see Figures 3B and 3C), the paper feed roller 43 and the slider 59 are connected, and the paper feed roller 43 can rotate together with the slider 59.

With this configuration, the slider 59 moves along the rotation shaft 51 between a connection position where the feed roller 43 and the transmission gear 55 are connected via the coupling 57, and a separation position where the feed roller 43 and the transmission gear 55 are separated. In the connection position shown in FIG. 3B, the slider 59 meshes with the coupling 57 and moves backward to connect with the feed roller 43. As a result, the rotation of the transmission gear 55 is transmitted to the feed roller 43 via the coupling 57 and the slider 59. However, as shown in FIG. 3C, even if the slider 59 moves to the connection position, if the slider 59 and the coupling 57 are separated, the rotation of the transmission gear 55 is not transmitted to the feed roller 43. On the other hand, in the separation position shown in FIG. 3A, the slider 59 is separated forward from the feed roller 43. As a result, the transmission of the rotation of the transmission gear 55 to the feed roller 43 is blocked.

As shown in FIG. 2, the slider 59 is supported by an operating lever 61 and moves between a connected position and a separated position. The operating lever 61 will be described with reference to FIG. 2, 4, 5A, 5B, and 5C. FIG. 4 is a cross-sectional view showing the operating lever 61, and FIGS. 5A, 5B, and 5C are perspective views showing the end of the operating lever 61.

As shown in FIG. 4, the operating lever 61 has a frame 63 that rotatably supports the slider 59, and a rod 65 that supports the frame 63. As shown in FIG. 5A, the rear end surface 65a of the rod 65 is inclined along the axial direction. A small diameter rod 69 that protrudes in the axial direction is provided at the center of the rear end surface 65a.

As shown in FIG. 2, the rod 65 is supported by a support member 17a supported by the paper feed unit 17 so as to be movable in the axial direction but not rotatable. The rod 65 is also biased rearward by a coil spring 67. In this way, the operating lever 61, i.e., the slider 59, is biased toward the paper feed roller 43, i.e., the connected position.

Next, the actuator 47 will be described with reference to Fig. 2, Fig. 6, Fig. 7A, and Fig. 7B. Fig. 6 is a perspective view showing the actuator 47 and the link lever 81, and Fig. 7A and Fig. 7B are side views showing the actuator 47, the link lever 81, and the operating lever 61.

The actuator 47 is a member that is driven (rotated) by a stack of documents placed on the document tray 7. As shown in FIG. 6, the actuator 47 has a rod 71, and an actuator arm 73 and a link arm 75 that protrude radially from the rod 71. The actuator arm 73 and the link arm 75 are arranged at a predetermined central angle with respect to the axis of the rod 71. A pin 77 that protrudes in the axial direction is provided at the tip of the link arm 75.

As shown in FIG. 2, the actuator 47 is disposed behind the paper feed holder 41. The rod 71 of the actuator 47 is rotatably supported by the paper feed unit 17 in a position parallel to the axial direction. The actuator 47 is maintained in an initial position (see FIG. 7A) in which the actuator arm 73 hangs down below the paper feed holder 41 and the link arm 75 extends downstream in the transport direction from the actuator arm 73 by a torsion coil spring 79 provided on the rod 71. When the actuator arm 73 is pressed by the document stack in the initial position, the rod 71 rotates in the clockwise direction in FIG. 2 (counterclockwise direction in FIG. 6, clockwise direction in FIG. 7A) against the biasing force of the torsion coil spring 79. When the document stack is not present, the rod 71 is biased by the torsion coil spring 79, and the actuator 47 rotates to the initial position (see FIG. 7A).

As shown in Figures 2 and 6, a link lever 81 is disposed between the actuator 47 and the operating lever 61. The link lever 81 converts the rotational motion of the actuator 47 into a reciprocating motion along the axial direction of the operating lever 61, i.e., a reciprocating motion between the connected position and the separated position of the slider 59.

As shown in FIG. 6, the link lever 81 has a rod 83 and a link arm 85 that protrudes radially from the rear end of the rod 83. A slit 85a is formed in the link arm 85 along the longitudinal direction. As also shown in FIG. 5A, the front end surface 83a of the rod 83 is inclined along the axial direction. An axial hole 87 (see FIG. 5A) is formed in the center of the front end surface 83a along the axial direction.

2, the link lever 81 is disposed downstream of the actuator 47 in the conveying direction. The rod 83 of the link lever 81 is supported by the support member 17a in a rotatable and axially immovable manner in a posture aligned with the rod 65 of the operating lever 61 in the axial direction. As shown in FIG. 6, the pin 77 of the link arm 75 of the actuator 47 is inserted into the slit 85a of the link arm 85 of the link lever 81. Furthermore, the small diameter rod 69 of the rear end surface 65a of the rod 65 of the operating lever 61 is inserted into the shaft hole 87 of the rod 83, connecting the link lever 81 and the operating lever 61 (see FIGS. 5A and 5B). The front end surface 83a of the rod 83 of the link lever 81 faces the rear end surface 65a of the rod 65 of the operating lever 61.

Next, the operation of converting the rotational motion of the actuator 47 into reciprocating motion along the axial direction of the operating lever 61 by the link lever 81 will be described. As shown in FIG. 7A, when no document stack is placed on the document tray 7, the actuator 47 rotates to its initial position. The pin 77 of the link arm 75 of the actuator 47 is inserted near the tip of the slit 85a of the link arm 85 of the link lever 81.

As shown in FIG. 5B, the front end surface 83a of the rod 83 of the link lever 81 and the rear end surface 65a of the rod 65 of the operating lever 35 are offset in the circumferential direction and face each other, so that the two surfaces do not completely abut. The operating lever 61 is supported so as to be movable in the axial direction, and the link lever 81 is supported so as not to be movable in the axial direction, so that the rear end surface 65a of the rod 65 of the operating lever 61 is pushed forward by the front end surface 83a of the rod 83 of the link lever 81, and the operating lever 35 moves forward against the biasing force of the coil spring 67. At this time, the small diameter rod 69 is guided along the shaft hole 87, and the operating lever 61 moves along the axial direction. As a result, the slider 59 moves to the separated position.

As shown in FIG. 7B, when the actuator arm 73 of the actuator 47 is pushed by the document stack D, the rod 71 rotates clockwise in the figure. This causes the link arm 75 to also rotate clockwise in the figure, and as the pin 77 moves along the slit 85a, it presses one side of the slit 85a and pushes up the link arm 85 of the link lever 81. This causes the rod 83 of the link lever 81 to rotate counterclockwise in the figure.

As shown in FIG. 5B, when the rod 83 of the link lever 81 rotates counterclockwise in the figure, the front end face 83a of the rod 83 of the link lever 81 and the rear end face 65a of the rod 65 of the operating lever 35 coincide in the circumferential direction and come into contact with each other as shown in FIG. 5C. This releases the link lever 81 from pressing the operating lever 61, and the operating lever 61 is biased by the coil spring 67 to move backward. As a result, the slider 59 moves to the connected position.

In this way, the rotational motion of the actuator 47 caused by the document stack is converted via the link lever 81 into a reciprocating motion along the axial direction of the operating lever 61, that is, a reciprocating motion between the separated position and the connected position of the slider 59.

Next, the feed roller 45 will be described with reference to FIG. 2 again. The feed roller 45 is disposed between the upstream ends of a pair of side plates of the paper feed holder 41 in the transport direction. The rotation shaft of the feed roller 45 is rotatably supported by the pair of side plates. A transmission gear (not shown) is fixed to the rotation shaft. The transmission gear meshes with the transmission gear 55 of the rotation shaft 51 via a plurality of idle gears 91 (see FIG. 1) supported by the side plates. When the transmission gear 55 of the rotation shaft 51 rotates, the feed roller 45 rotates in the same direction as the transmission gear 55.

As described above, the paper feed holder 41 can rotate vertically around the rotation shaft 51. The paper feed holder 41 rotates downward to move between a paper feed position in which the feed roller 45 abuts against the topmost document in the document stack placed on the document tray 7, and a non-paper feed position in which the feed roller 45 rotates upward to move away from the document stack.

The paper feed holder 41 further supports a pair of stoppers 93 that regulate the position of the leading edge of the document stack. The stoppers 93 are rotatably supported on the outer surfaces of a pair of side panels, with their leading edges hanging down below the lower end of the paper feed holder 41. When the paper feed holder 41 rotates to the paper feed position, the pair of stoppers 93 become rotatable relative to the paper feed holder 41, allowing the document to be fed out. On the other hand, when the paper feed holder 41 rotates to the non-paper feed position, the stoppers 93 become unable to rotate relative to the paper feed holder 41, regulating the position of the leading edge of the document stack.

Next, the separation pad 33 will be described with reference to FIG. 1. The separation pad 33 is supported by the paper feed section 17 so as to abut against the paper feed roller 43 from below. The separation pad 33 is biased by a coil spring 101 and abuts against the paper feed roller 43 with a predetermined pressure. This forms a separation nip N between the separation pad 33 and the paper feed roller 43.

The document feeding operation in the document transport device 1 having the above configuration will be described with reference to Figures 8A to 12B. Figures 8A, 9A, 10A, and 11A are views of the paper feed unit 31 as seen from the front, and Figures 8B, 9B, 10B, and 11B are views of the paper feed unit 31 as seen from the left side. Figures 12A and 12B are perspective views showing the paper feed roller 43, slider 59, coupling 57, and transmission gear 55.

As shown in FIG. 8A, when no document stack is placed on the document tray 7, the paper feed holder 41 is rotated to a non-feeding position. The actuator 47 is rotated to the initial position, and the actuator arm 73 hangs down below the paper feed holder 41. Furthermore, as shown in FIG. 8B, the rear end surface 65a of the operation lever 61 faces the front end surface 101a of the link lever 81 with a circumferential shift, and both surfaces are not completely abutted. In other words, the operation lever 61 is pushed by the link lever 81 and moves forward against the biasing force of the coil spring 67. As a result, the slider 59 moves to the separated position, and the transmission of the rotational force of the rotating shaft 51 to the paper feed roller 43 is interrupted. The ratchet teeth 59b of the slider 59 mesh with the ratchet teeth 57c of the coupling 57, and the protruding piece 55a of the transmission gear 55 faces the front end surface 57d of the coupling 57 (see FIG. 3A).

As shown in FIG. 9A, when a stack of documents D is placed on the document tray 7 and the leading edge of the stack of documents D is brought into contact with the stopper 93, the actuator arm 73 of the actuator 47 is pushed by the stack of documents D, and as shown in FIG. 7B, the rod 71 rotates in the clockwise direction in the figure. As a result, as described above, the link lever 81 rotates and the rear end surface 65a of the operating lever 61 coincides with the front end surface 83a of the link lever 81 in the circumferential direction and both surfaces abut. As a result, the operating lever 61 is biased by the coil spring 67 and moves backward. As a result, as shown in FIG. 9B, the slider 59 moves away from the coupling 57 and to the coupling position.

The rotation of the actuator 47 is transmitted to the rotating shaft 51, which rotates and rotates the paper feed holder 41 to the paper feed position. When the feed roller 45 comes into contact with the topmost document in the document stack D, the torque limiter causes the rotating shaft 51 to rotate freely relative to the paper feed holder 41.

When the rotary shaft 51 rotates, the transmission gear 55 rotates together with the rotary shaft 51, and the feed roller 45 rotates via the idle gear 91 (see FIG. 1). Because the paper feed holder 41 has rotated to the paper feed position, the stopper 93 becomes rotatable relative to the paper feed holder 41, and the topmost document D1 that the feed roller 45 is in contact with is sent toward the separation nip N, as shown in FIG. 10A.

When the transmission gear 55 rotates, the rear end surface of the projection 55a of the transmission gear 55 pushes the inclined front end surface 57d of the coupling 57 backward, and the ratchet teeth 57c of the coupling 57 mesh with the ratchet teeth 59b of the slider 59 (see FIG. 3B). As shown in FIG. 10B, when the rotating shaft 51 rotates further and the side surface of the projection 55a of the transmission gear 55 abuts against the side surface of the projection 57b of the coupling 57, the coupling 57 rotates together with the transmission gear 55. As a result, the rotation of the transmission gear 55 is transmitted to the paper feed roller 43 via the coupling 57 and the slider 59, and the paper feed roller 43 rotates. In this way, the document sent by the feed roller 45 is separated at the separation nip N and transported by the paper feed roller 43 toward the first transport roller pair 19.

Then, the document is transported along the transport path 15 by the first transport roller pair 19, and the document is transported along the transport path 15 as described above.

As shown in FIG. 11A, the last document Dn in the document stack passes through the separation nip N and is then transported along the transport path 15 by the first transport roller pair 19.

When the last document Dn passes through the actuator 47, the actuator 47 is biased by the torsion coil spring 79 to rotate to the initial position (see FIG. 8A). Then, the link lever 81 rotates, and the front end surface 83a of the rod 83 presses the rear end surface 65a of the rod 65 of the operating lever 61. This causes the operating lever 61 to move forward, and the slider 59 tries to move to the separated position. However, as shown in FIG. 10B, the slider 59 is engaged with the coupling 57, so resistance is applied to the movement of the slider 59 to the separated position.

12A and 12B, the document transport operation by the feed roller 43 and the first transport roller pair 19 will be described. The rotation speed (circumferential speed) V1 of the rotating shaft 51 is set to be slightly slower than the rotation speed (circumferential speed) V2 of the first transport roller pair 19 (see FIG. 1). Therefore, when the document is transported by the first transport roller pair 19, the document is transported at a speed corresponding to the circumferential speed V2 of the first transport roller pair 19. Since the feed roller 43 is in contact with the document, as shown in FIG. 12A, the feed roller 43 and the slider 59 connected to the feed roller 43 rotate at a speed corresponding to the circumferential speed V2 of the first transport roller pair 19. This speed is faster than the circumferential speed V1 of the rotating shaft 51 (transmission gear 55).

As a result, as shown in FIG. 12B, the second surface of the ratchet teeth 59b of the slider 59 presses against the second surface of the ratchet teeth 57c of the coupling 57, moving the coupling 57 forward. This eliminates the resistance to the movement of the slider 59 to the separated position, and the slider 59 moves to the separated position as shown in FIG. 11B.

In this way, after the last document Dn in the document stack passes through the separation nip N, the slider 59 moves to the separated position and the transmission of rotational force to the feed roller 43 is interrupted, so that the feed roller 43 does not rotate after the last document Dn is fed. In other words, no friction occurs between the feed roller 43 and the separation pad 33.

As is clear from the above description, according to the present invention, by using the slider 59, the feed roller 43 can be rotated appropriately without using an electromagnetic clutch. The slider 59 moves between the connected position and the separated position by the actuator 47 driven by the document placed on the document tray 7. That is, when the actuator 47 rotates when the document is fed, the slider 59 moves to the connected position, and the rotational force of the rotating shaft 51 is transmitted to the feed roller 43, causing the feed roller 43 to rotate and transport the document fed by the feed roller 45 to the transport path 15. Then, when the actuator 47 returns to its initial position after the last document has passed through the separation nip N, the slider 59 moves to the separated position and stops the rotation of the feed roller 43. As a result, no friction occurs between the feed roller 43 and the separation pad 33, and both do not wear out. Therefore, even in a low-cost model that does not use an electromagnetic clutch, the separation performance at the separation nip N can be maintained.

In addition, by using the link lever 81, the rotational motion of the actuator 47, which rotates due to the document being fed, can be easily converted into reciprocating motion of the slider 59 between the connected position and the separated position.

Furthermore, since a coupling 57 is interposed between the slider 59 and the transmission gear 55, the movement of the slider 59 along the axial direction can be reliably transmitted to the transmission gear 55 by the coupling 57.

Furthermore, because the coupling 57 and the slider 59 are connected by a ratchet mechanism, the rotational force of the transmission gear 55 can be reliably transmitted from the coupling 57 to the feed roller 43 via the slider 59. Furthermore, because the circumferential speed of the feed roller 43 is faster than the circumferential speed of the transmission gear 55, the coupling 57 can be separated from the slider 59 after the last document leaves the separation nip N. This allows the slider 59 to be moved smoothly to the separated position.

Although the present invention has been described with respect to specific embodiments, the present invention is not limited to the above embodiments. Those skilled in the art may modify the above embodiments without departing from the scope and spirit of the present invention.

1 Document transport device 7 Document tray 33 Separation pad (separation member)
43 Paper feed roller 45 Feed roller 47 Actuator 51 Rotating shaft 57 Coupling 59 Slider 61 Operation lever 81 Link lever

Claims (4)

an actuator that rotates when a document is placed on the document tray;
a feed roller for feeding the document;
a feed roller that is rotatably supported on a rotating shaft that is driven to rotate, and that conveys the document fed by the feed roller by being rotated by receiving a rotational force of the rotating shaft, and that contacts a separating member to form a separation nip;
a slider supported movably along the rotation shaft between a connection position where the paper feed roller and the rotation shaft are connected to transmit the rotation force to the paper feed roller and a separation position where the slider is separated from the paper feed roller to interrupt the transmission of the rotation force from the rotation shaft to the paper feed roller;
an operating lever that rotatably supports the slider and moves along a direction parallel to an axial direction of the rotation shaft by rotation of the actuator,
When the document is not placed on the document tray and the actuator is not rotating, the operation lever moves the slider to the separated position,
When the document is placed on the document tray and the actuator rotates, the operation lever moves to move the slider to the connecting position. The document transport device according to claim 1, further comprising a link lever provided between the actuator and the operating lever, which converts the rotational motion of the actuator into a reciprocating motion along a direction parallel to the axial direction of the rotation shaft of the operating lever. A transmission gear fixed to the rotating shaft;
a coupling between the transmission gear and the slider, the coupling being movable along the rotation shaft and rotatable integrally with the transmission gear;
3. The document transport device according to claim 1, wherein, at the connecting position, the slider is connected to the coupling and is connected to the paper feed roller. 2. The document transport device according to claim 1, wherein, at the connected position, the feed roller and the slider are connected by a ratchet mechanism.

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