JP7494694B2 - SHEET FEEDING DEVICE, SHEET CONVEYING DEVICE AND IMAGE READING DEVICE - Google Patents

Description

This disclosure relates to a sheet feeding device that feeds sheets placed on a tray toward a conveying path.

As an image reading device such as a scanner, an image reading device has been developed that is equipped with a sheet feeding device that feeds a sheet-like document placed on a tray toward a transport path using a feeding roller (feeding roller), transports the fed document along the transport path to a reading position using a transport roller, and reads the image of the document at the reading position (Patent Document 1).

Figure 22(a) is a schematic diagram for explaining the sheet feeding device 900 described in Patent Document 1, in which the left-right direction is the X-axis direction, the up-down direction is the Y-axis direction, and the direction perpendicular to these is the Z-axis direction.

As shown in the figure, the sheet delivery device 900 has a delivery roller 901 and a paper feed roller 902 downstream of the delivery roller 901 in the sheet transport direction (arrow A direction) supported for free rotation by a holder 903, and the holder 903 is configured to be able to swing up and down around the rotation axis 921 of the paper feed roller 902 between the position shown by the solid line and the position shown by the dashed line.

The position indicated by the solid line is the position where the delivery roller 901 contacts the topmost document 932 of the document stack 931 on the tray 930, and the position indicated by the dashed line is the position where the delivery roller 901 is separated from the document 932.

When the original 932 is to be fed, the holder 903 moves to the position shown by the solid line, the feed roller 901 rotates to feed the original 932, and the fed original 932 is transported downstream in the sheet transport direction along the transport path 905 by the feed roller 902. This series of operations is called original feeding. When the original feeding is completed, the holder 903 moves from the position shown by the solid line to the position shown by the dashed line by the driving force of a drive source (not shown) such as a motor.

The holder 903 is supported by the rotating shaft 921 of the paper feed roller 902 so that it can move freely in the rotational direction, and is structured so that when the drive force of the drive source is stopped, the holder 903 descends under its own weight. Therefore, after the holder 903 rises to the position shown by the dashed line, when the drive is stopped, it descends to the position shown by the solid line. If the holder 903 descends on its own, the delivery roller 901 will remain in contact with the tray 930, making it difficult to perform operations such as setting a new document on the tray 930. Therefore, a locking section 910 is provided to lock the holder 903 so as to prevent the holder 903, which has risen to the dashed line position, from descending freely.

Figure 22(b) is a schematic enlarged view illustrating the configuration of the locking portion 910.

As shown in the figure, the locking section 910 includes a protrusion 911 parallel to the Z-axis direction provided on the right end of the holder 903, an engagement lever 912 that can swing in the directions of arrows B and C around an axis 915 provided on the top wall 914 on the device body side, and a spring 913 that applies a force to the engagement lever 912 in the direction of arrow C.

When the holder 903 moves upward in the direction of arrow D, the protrusion 911 of the holder 903 pushes up the inclined surface 918 on the claw portion 919 of the engagement lever 912, causing the engagement lever 912 to swing in the direction of arrow B against the biasing force of the spring 913 around the shaft 915 by an amount corresponding to the inclination angle of the inclined surface 918 (the position shown by the dashed line).

After that, when the protrusion 911 of the holder 903 passes through the inclined surface 918 and enters the inner surface 917 of the claw portion 919, the engaging lever 912 swings in the direction of arrow C due to the biasing force of the spring 913 and returns to its original position shown by the solid line, so that the protrusion 911 of the holder 903 engages with the claw portion 919 of the engaging lever 912 (the state shown by the dashed line in Figure 22 (a)). This locks the holder 903. Note that Figure 11 of Patent Document 1 discloses a configuration in which a disengagement portion (reference number 18) for releasing this lock is separately provided.

JP 2020-63147 A

In the above-described configuration of the locking section 910, when the protrusion 911 of the holder 903 rises and hits the inclined surface 918 of the engagement lever 912, a loud collision sound is generated, and when the holder 903 passes the inclined surface 918, the upper surface 951 of the holder 903 continues to collide with the upper wall 914 with the same momentum, generating a collision sound.

To reduce the impact noise between the holder 903 and the upper wall 914, a sponge-like cushioning material 955 (Figure 22(a)) could be attached to the underside 941 of the upper wall 914, but this would increase the number of parts.

The above problem is not limited to image reading devices, but can also occur in a sheet feeding device in an image forming device that feeds paper placed on a tray of a paper feed cassette and forms an image on the paper.

The present disclosure has been made in consideration of the above problems, and aims to provide a sheet delivery device that can reduce the number of parts and reduce the impact noise that occurs when the holder is lifted, in a configuration in which a holder that rotatably supports a roller that delivers a sheet is lifted by the driving force of a drive unit and then locked, as well as a sheet transport device and image reading device that include the same.

To achieve the above object, the sheet dispensing device disclosed herein is a sheet dispensing device that dispenses sheets on a tray with a roller, and includes a holder that rotatably supports the roller, a support section that supports the holder so that it can move freely up and down, a drive section that raises the holder, a wall body located above the holder, and a locking member located below the wall body and provided on one of the holder and the wall body, and a buffer member located on the other, the buffer member is pressed by the rising holder and compressively deforms between the wall body, and after the drive is stopped, the locking member locks onto a part of the buffer member in the vertical direction, causing the raised holder to hang from the wall body via the locking member.

The buffer member may be a compression coil spring, the locking member may have a claw portion, and a portion of the buffer member may be a portion of the winding of the compression coil spring, and after the drive is stopped, the claw portion may catch on a portion of the winding, causing the holder to enter the hanging state.

Here, the locking member protrudes from the holder, the compression coil spring has an upper end in the axial direction supported by the underside of the wall and a lower end that is a free end, the claw portion is hook-shaped, has an inclined surface on the outside that rises from the tip to the base end, and has a hooking surface on the inside that hooks a part of the winding, and while the holder is rising, the lower end of the compression coil spring is pushed up by the holder and the compression coil spring is compressed and deformed, while the claw portion enters the inner space of the deformed compression coil spring, and the inclined surface of the claw portion moves upward while deforming the winding in the pressing direction by pushing the winding from the inner circumference side to the outer circumference side by an amount corresponding to the inclination angle, and after driving is stopped, a part of the winding enters the hooking surface from the tip of the claw portion, thereby causing the claw portion to hook onto the winding.

The locking member may be protruding from the holder, the compression coil spring has an upper end in the axial direction supported by the underside of the wall and a lower end that is a free end, the claw portion is hook-shaped, has an inclined surface on the outside that rises from the tip to the base end, and has a hooking surface on the inside that hooks a part of the winding, and while the holder is rising, the lower end of the compression coil spring is pushed up by the holder and the compression coil spring is compressed and deformed, and the claw portion moves upward while deforming the winding of the deformed compression coil spring in the pressing direction as the inclined surface of the claw portion pushes the winding of the deformed compression coil spring from the outside toward the inner circumference by an amount corresponding to the inclination angle, and after the drive is stopped, a part of the winding enters the hooking surface from the tip of the claw portion, and the claw portion hooks the winding.

Furthermore, the locking member is provided on the lower surface of the wall, the lower end of the compression coil spring in the axial direction is supported by the holder, and the upper end is a free end, the claw portion is hook-shaped, and has an inclined surface on the outside that descends from the tip to the base end, and an engagement surface on the inside on which a part of the winding is engaged; while the holder is rising, the upper end of the compression coil spring comes into contact with the wall and stops, and the lower end is pressed by the holder, causing compression deformation, while the inclined surface of the claw portion pushes the winding of the deformed compression coil spring from the outside toward the inner circumference by an amount corresponding to the inclination angle, so that the winding moves upward while being deformed in the pressing direction, and after the drive is stopped, part of the winding enters the engagement surface from the tip of the claw portion, causing the claw portion to engage the winding.

The compression coil spring may also be a cylindrical coil spring.

The buffer member may be a zigzag spring, the locking member may have a claw portion, and a part of the buffer member may be one of a number of bent portions of the zigzag spring, and after driving is stopped, the claw portion may be caught on one of the bent portions of the zigzag spring, thereby causing the holder to enter the hanging state.

Furthermore, a release unit for releasing the locking may be provided.

The spring may further include a release unit that releases the lock, and the release unit may include a pressing member that applies a pressing force to the winding of the compression coil spring in a direction to release the winding when a part of the winding is caught on the claw portion, thereby releasing the winding from the hook.

The locking member may further include a release section that releases the locking, and the locking member may have flexibility such that the tip side of the protruding direction relative to the base end elastically bends in a direction perpendicular to the protruding direction, and the release section may include a pressing member that, when a part of the winding is caught on the claw portion, applies a pressing force to the locking member in a direction to release the hook, thereby bending the locking member, thereby releasing the hooking.

Here, the drive unit includes a transmission mechanism that applies a rotational drive force to the rotation shaft of the roller after the drive of the holder stops and the holder is in the hanging state, and the pressing member is a cam that is provided on the rotation shaft of the roller and rotates integrally with the rotation shaft of the roller, and the pressing force may be applied to the pressing target by the peripheral surface of the cam.

Here, when the roller is a feed roller, the holder further includes a feed roller located downstream of the feed roller in the sheet transport direction, the holder rotatably supports the feed roller and the feed roller, the drive unit can switch between driving forces for forward rotation during sheet transport and reverse rotation in the opposite direction to the forward rotation to the feed roller and the feed roller via the transmission mechanism, and the support unit supports the holder so that the side on which the feed roller is supported can be swung up and down and freely moved around the rotation axis of the feed roller, and when the drive force for the forward rotation is applied, the holder can be moved in a downward direction to the holder. When a driving force for the reverse rotation is applied, the holder is supported so that a force in an upward direction is applied to the holder, and the cam is connected to the rotating shaft of the pay-out roller via a one-way clutch, and the one-way clutch is a clutch that transmits the driving force to the cam when the driving force for the forward rotation is applied to the rotating shaft of the pay-out roller, and does not transmit the driving force to the cam when the driving force for the reverse rotation is applied, and when the lock is released, the driving force for the forward rotation may be transmitted from the drive unit to the cam via the transmission mechanism, the rotating shaft of the pay-out roller, and the one-way clutch.

The sheet conveying device according to the present disclosure is characterized in that it includes the sheet feeding device described above and conveys the sheet fed by the sheet feeding device.

The image reading device according to the present disclosure is an image reading device that obtains image data by reading an image on a sheet transported by a sheet transport unit, and is characterized in that the sheet transport unit includes the above-mentioned sheet transport device.

By doing this, the cushioning material both absorbs the collision energy with the holder while it is rising and locks the holder after it has risen, making it possible to reduce the number of parts compared to conventional methods while also reducing the noise caused by collisions with the holder.

1 is a schematic diagram showing a configuration of an MFP according to a first embodiment; FIG. 2 is a schematic cross-sectional view of the document transport device. 13 is a diagram showing a state in which the delivery roller is in contact with the upper surface of a document placed on a document tray. FIG. 4 is a perspective view showing a configuration of a drive mechanism for swinging the holder up and down. FIG. 5 is a schematic rear view of the locking portion and the unlocking portion as viewed in the direction of the arrow K shown in FIG. 4. 6 is a schematic perspective view of a locking portion and an unlocking portion shown in FIG. 5 as viewed in the direction of an arrow U. FIG. 6 is a schematic perspective view of a locking portion and an unlocking portion shown in FIG. 5 as viewed in the direction of an arrow V. FIG. 13 is a schematic rear view showing the holder rising from the first position due to reverse rotation of the drive motor. FIG. 9 is a schematic rear view showing a state in which the holder is further raised from the position shown in FIG. 8 . 13 is a schematic rear view showing a state in which the claw portion of the locking projection is caught on a part of the winding of the compression coil spring after driving is stopped. FIG. 13 is a schematic rear view showing how the claw portion of the locking projection is disengaged from the coil of the compression coil spring when normal rotation is started after driving is stopped. FIG. 13 is a schematic rear view for explaining a configuration example of a locking protrusion according to embodiment 2. FIG. 13A is a schematic perspective view of the locking projection shown in FIG. 12, and FIG. 13B is a schematic plan view of the locking projection shown in FIG. 11 is a schematic rear view showing a state in which the holder is raised from the first position and the compression coil spring is pressed and compressed by the holder. FIG. 15 is a schematic rear view showing a state where the holder 24 is further elevated from the position shown in FIG. 14 and then stopped being driven. 13 is a schematic rear view showing a state in which the feed roller and the delivery roller start rotating in the forward direction as forward rotation starts after driving is stopped. FIG. 13A is a schematic perspective view of a zigzag spring according to a third embodiment, and FIG. 11 is a schematic rear view showing only the peripheral portion of the zigzag spring, showing a state in which the claw portion of the locking projection is caught by the zigzag spring; FIG. 13 is a schematic rear view showing how the claw portion of the locking projection is disengaged from the bent portion of the zigzag spring when normal rotation is started after driving is stopped; FIG. 1A is a schematic rear view showing the configuration of a modified example, FIG. 1B is a schematic enlarged oblique view of an engagement protrusion of a modified example, and FIG. 1C is a schematic view showing the positional relationship between the engagement protrusion, the compression coil spring, and the cam when the engagement protrusion is viewed from the direction of the arrow W shown in FIG. 11 is a schematic partial rear view showing only the locking projection and its surroundings when the holder is lifted and then stopped. FIG. 1A is a schematic diagram for explaining a conventional sheet feeding device, and FIG. 1B is a schematic enlarged view for explaining the configuration of a locking portion.

Hereinafter, an embodiment of an image reading device including a sheet feeding device according to the present disclosure will be described with reference to the drawings, taking a multi-function peripheral (hereinafter, referred to as an MFP) as an example.
<First embodiment>
[1] Overall Configuration of MFP FIG. 1 is a schematic diagram showing the configuration of an MFP 100 according to this embodiment, in which the left-right direction when viewing MFP 100 from the front is indicated as the X-axis direction, the up-down direction is indicated as the Y-axis direction, and the depth direction perpendicular to these is indicated as the Z-axis direction.

As shown in the figure, the MFP 100 includes an image reading device 101 and an image forming device 102. The image reading device 101 includes a document transport device 111 and a reading device main body 112.

The document transport device 111 feeds documents (sheets) on a tray one by one toward the transport path, and transports them along the transport path to the reading position of the reading device main body 112.

The reading device main body 112 optically reads the image of the document transported to the reading position by the document transport device 111 to obtain image data.

The image forming device 102 has paper feed cassettes, 121, 122, 123, and 124 in the example shown in the figure, that store paper (sheets) on which images are formed, and when executing a job, it feeds out paper one sheet at a time from the paper feed cassette selected and transports it along a transport path (not shown), forms an image based on image data read by the image reading device 101 on the transported paper, and outputs the sheet with the image formed on it.
[2] Configuration of Original Transporting Device 111 FIG. 2 is a schematic cross-sectional view of the original transporting device 111 in the XY plane.

As shown in the figure, the document transport device 111 includes a document tray 1 on which documents are placed, a sheet feed section 2, a sheet transport section 3, and a paper discharge tray 4.

The sheet delivery section 2 feeds the originals (sheets) on the original tray 1, and includes a delivery roller 21, a paper feed roller 22 located downstream of the delivery roller 21 in the sheet transport direction (arrow E direction), a handling roller 23 located directly below the paper feed roller 22, and a holder 24 that rotatably supports each of the delivery roller 21 and the paper feed roller 22.

The holder 24 is supported on the rotation shaft 221 of the paper feed roller 22 so that the end 241 on the side where the delivery roller 21 is located can swing freely in the directions of arrows F (downward) and G (upward). The holder 24 swings up and down by the driving force of the drive mechanism 25 (Figure 4), which will be described later.

Figure 3 shows the holder 24 shown in Figure 2 moving downward and the delivery roller 21 coming into contact with the top surface of the topmost document 6 in the document stack 5 placed on the document tray 1.

When the delivery roller 21 is in contact with the document 6, the delivery roller 21 rotates in the direction of the arrow I (forward rotation), and the rotational driving force of the delivery roller 21 is applied to the document 6, causing the document 6 to be delivered in the direction of the arrow E.

When the original 6 fed in the direction of arrow E by the feed roller 21 passes between the feed roller 22 and the separation roller 23, the rotational driving force of the feed roller 22 rotating in the direction of arrow J (forward rotation) is further added, and the original is sent to the sheet conveying section 3 (FIG. 2) downstream in the sheet conveying direction (original feeding). Note that when two or more originals are fed by the feed roller 21 in a stacked state (multiple feed), the uppermost original 6 is separated by the separation roller 23 so that only the topmost original 6 passes between the feed roller 22 and the separation roller 23.

Returning to FIG. 2, the sheet transport unit 3 transports the document 6 from the sheet delivery unit 2 along the transport path 39 by transport roller pairs 31 and 32, and passes it over the reading unit 113 arranged at the reading position of the reading device main body 112. As the document 6 passes over the reading unit 113, the image of the document 6 is read by the reading unit 113. The document 6 that has passed over the reading unit 113 is discharged outside the machine by the transport roller pair 33 and the discharge roller pair 34 on the downstream side in the sheet transport direction, and is stored in the paper discharge tray 4.

When the document feeding is completed, the holder 24 moves upward from the position shown in Fig. 3 to the position shown in Fig. 2, i.e., the position where the feed roller 21 is above the document 6 (a position separated from the document 6). The position of the feed roller 21 shown in Fig. 2 is called the retracted position, and the position shown in Fig. 3 is called the feed position, and the position of the holder 24 when the feed roller 21 is in the feed position is called the first position, and the position of the holder 24 when it is in the retracted position is called the second position. The retracted position of the feed roller 21 is higher than the feed position, and a wall 98 of the device main body 95 is located directly above the holder 24 that rotatably supports the feed roller 21, as an upper wall 98.
[3] Configuration of Drive Mechanism 25 FIG. 4 is a perspective view showing the configuration of the drive force transmission mechanism 25 for swinging the holder 24 up and down.

As shown in the figure, the driving force transmission mechanism 25 transmits the rotational driving force of the driving motor 251 as a driving source to the rotating shaft 221 of the paper feed roller 22 via a gear train 252 and an electromagnetic clutch 253. Here, the rotating shaft 259 of the driving motor 251 can be switched to rotate in either direction of the arrows 95a and 96a. The electromagnetic clutch 253 switches the transmitted rotational driving force on and off (on and off). The rotating shaft 221 of the paper feed roller 22 is supported by the holder 24 so as to be rotatable forward and backward via the bearing members 245 and 246 provided on the holder 24. Since the rotating shaft 221 of the paper feed roller 22 and the holder 24 are rotatable forward and backward relative to each other, it can be said that the rotating shaft 221 of the paper feed roller 22 and the bearing members 245 and 246 form a support part that supports the holder 24 so as to be freely movable up and down.

The rotational force transmitted to the rotating shaft 221 of the paper feed roller 22 is transmitted to the rotating shaft 211 of the delivery roller 21 via a driving force transmission mechanism 26 consisting of a gear train. In the sense that they are mechanisms for transmitting driving force to the delivery roller 21, the driving force transmission mechanisms 25 and 26 can be considered as a single driving force transmission mechanism.

Here, two torque limiters 255, 256 are provided on the rotating shaft 221 of the paper feed roller 22. When the transmitted torque is lower than a certain value, regardless of whether the direction of rotation of the rotating shaft 259 of the drive motor 251 is the direction of arrows 95a, 96a, each torque limiter transmits a rotational force according to the magnitude of the transmitted torque in that direction, but has the characteristic of slipping when the torque exceeds a certain value.

When the rotating shaft 259 of the drive motor 251 rotates (reverses) in the direction of the arrow 95a and the electromagnetic clutch 253 is turned on, the rotating shaft 221 of the paper feed roller 22 rotates (reverses) in the direction of the arrow 95, and the rotational force of this rotating shaft 221 is transmitted to the rotating shaft 211 of the delivery roller 21 via the drive force transmission mechanism 26. This causes the rotating shaft 211 of the delivery roller 21 to rotate (reverses) in the direction of the arrow 95b.

When the rotation shaft 221 of the paper feed roller 22 rotates in the reverse direction (in the direction of arrow 95), a frictional force is generated between the rotation shaft 221 of the paper feed roller 22 and the bearing members 245, 246 provided on the holder 24, which generates a moment that rotates the holder 24 in the direction of arrow 95 around the rotation shaft 221 of the paper feed roller 22. The generation of this moment corresponds to the application of a force in an upward direction to the holder 24. This causes the holder 24 to rise, and the delivery roller 21 to reach the retracted position shown in FIG. 2.

When the holder 24 hits the compression coil spring 52 of the locking portion 29 while it is rising, and the compression coil spring 52 is compressed and deformed by a predetermined amount, the torque limiter 255 starts to slip and the holder 24 will not rise any further.

Conversely, when the rotating shaft 259 of the drive motor 251 rotates in the direction of the arrow 96a (forward rotation) and the electromagnetic clutch 253 is turned on, the rotating shaft 221 of the paper feed roller 22 rotates in the direction of the arrow 96 (forward rotation), and the rotational force of this rotating shaft 221 is transmitted to the rotating shaft 211 of the delivery roller 21 via the driving force transmission mechanism 26. This causes the rotating shaft 211 of the delivery roller 21 to rotate in the direction of the arrow 96b (forward rotation).

When the rotating shaft 221 of the paper feed roller 22 rotates forward (in the direction of arrow 96), a frictional force is generated between the rotating shaft 221 of the paper feed roller 22 and the bearing members 245, 246 provided on the holder 24, which generates a moment that rotates the holder 24 in the direction of arrow 96 around the rotating shaft 221 of the paper feed roller 22. The generation of this moment corresponds to a force being applied to the holder 24 in a downward direction. This causes the holder 24 to descend, and the delivery roller 21 to reach the delivery position shown in FIG. 3.

When the delivery roller 21 is pressed against the document stack 5 on the document tray 1 as shown in FIG. 3 while the holder 24 is descending, the torque limiter 256 starts to slip and the delivery roller 21 will not descend any further.

The rotation and stopping of the drive motor 251 is controlled by a control unit (not shown). This control is roughly as follows.

That is, when feeding the original, as shown in FIG. 3, the holder 24 is in the first position, and the feed roller 21 is in the feed position, the drive motor 251 rotates forward (in the direction of the arrow 96a) while the electromagnetic clutch 253 is turned on. The original 6 is fed by the forward rotation of the feed roller 21 and the feed roller 22. When feeding multiple originals one by one, when the rear end of the Nth original passes the feed roller 21, the drive motor 251 continues to rotate forward while the electromagnetic clutch 253 is temporarily turned off. The Nth original continues to be transported by the transport force of the sheet transport unit 3 even if the electromagnetic clutch 253 is turned off. After that, when it is time to start feeding the (N+1)th original, the electromagnetic clutch 253 is switched on. The electromagnetic clutch 253 is alternately switched off and on until the feeding of the last original is completed.

When document feeding is completed, that is, when the rear end of the last document has passed the feed roller 22, the drive motor 251 is rotated in the reverse direction (in the direction of arrow 95a) and the electromagnetic clutch 253 is turned on. This causes the holder 24 to rise from the first position to the second position, and the delivery roller 21 to reach the retracted position (Figure 2). When the holder 24 has risen to the second position, the drive motor 251 is turned off (stopped) and the electromagnetic clutch 253 is also turned off. This means that the driving force of the drive motor 251 is no longer applied to the holder 24.

Similar to the mechanism described in the Background Art section, when the application of the driving force of drive motor 251 is stopped (or/and electromagnetic clutch 253 is turned off), holder 24 is allowed to rotate freely about rotation shaft 221 of paper feed roller 22 by bearing members 245, 246, and rotates in the direction of arrow 96 around rotation shaft 221 of paper feed roller 22 due to the action of moment in the direction of arrow 96 caused by its own weight, forming a freely movable shaft support structure that descends from the second position to the first position. In order to prevent holder 24 from falling due to its own weight, in this embodiment, the above-mentioned locking portion 29 is provided, and further, an unlocking portion 60 for unlocking locking portion 29 is provided.
[4] Configuration of lock unit 29 and unlock unit 60 Fig. 5 is a schematic rear view of lock unit 29 and unlock unit 60 as viewed from the direction of arrow K in Fig. 4, Fig. 6 is a schematic perspective view of lock unit 29 and unlock unit 60 as viewed from the direction of arrow U, and Fig. 7 is a schematic perspective view of lock unit 29 and unlock unit 60 as viewed from the direction of arrow V. Note that some members not necessary for the explanation, such as drive mechanism 25, are omitted from Figs. 5 to 7, and an example is shown in which pay-out roller 21 is in the pay-out position and holder 24 is in the first position.

As shown in Figures 5 to 7, the locking portion 29 has a locking projection 51 (locking member) and a compression coil spring 52 (buffer member).

The locking projection 51 has a base end 510 rising from the upper surface 244 of a plate-shaped base 243 erected on the rear surface 242 of the holder 24, and a hook-shaped claw portion 512 is provided at an upper end 511 continuous with the base end 510. The overall length (length in the protruding direction) of the locking projection 51 is, for example, about 10 to 15 mm. An inclined surface 515 is provided on the outer side of the claw portion 512.

The inclined surface 515 rises from the hook tip of the claw portion 512 toward the base end (rear end), and corresponds to a surface that is inclined at a predetermined angle, for example an angle within the range of 30° to 60°, with respect to the axial direction of the compression coil spring 52 when the locking projection 51 is assumed to be located directly below the compression coil spring 52.

The locking protrusion 51 is made of a resin such as PE (polyethylene) or PC (polycarbonate), but is not limited to this and may be made of a metal such as iron.

In the above description, the base 243 is a part of the holder 24, and the locking projection 51 is a separate member from the holder 24. However, this is not limited to the above, and the holder 24, base 243, and locking projection 51 may be integrally formed. In any case, the locking projection 51 is included in the configuration provided on the holder 24.

The compression coil spring 52 is an elastically deformable cylindrical coil spring made by winding a metal wire such as iron in a spiral shape at a constant pitch (equidistant intervals), and its free axial length is, for example, about 20 to 30 mm.

One end (upper end) 521 of the compression coil spring 52 in the longitudinal direction is fitted into a support tube 981 of about 2 to 3 mm height provided on the underside 99 of the wall 98 and is supported by the wall 98, and the other end (lower end) 522 in the longitudinal direction is a free end, and when the payout roller 21 is in the payout position as shown in Figures 5 to 7, the lower end 522 is in a floating state. Note that the support of the upper end 521 of the compression coil spring 52 to the wall 98 is not limited to being fitted into the support tube 981, but may be fixed to the wall 98 by adhesive or the like.

The compression coil spring 52 has a predetermined positional relationship with the locking protrusion 51 such that the inner diameter of the coil portion 520 is larger than the maximum width of the claw portion 512 of the locking protrusion 51, and when the holder 24 rotates in the direction of the arrow 95 around the rotation axis 221 of the paper feed roller 22, that is, rises, the claw portion 512 of the locking protrusion 51 protruding from the holder 24 enters the inner space 528 (FIG. 7) of the compression coil spring 52, and the inclined surface 515 of the claw portion 512 pushes the winding 525 of the coil portion 520 from the inner periphery side toward the outer periphery by an amount corresponding to the inclination angle of the inclined surface 515, thereby sliding upward while deforming in the pressing direction. The material of the compression coil spring 52 is not limited to metal, and may be, for example, a resin such as PE.

The unlocking unit 60 includes a plate cam 63 with a built-in one-way clutch 69 (broken line). The plate cam 63 is an eccentric cam, and is fitted into the tip of the shaft portion 21a that protrudes outward from the back surface 242 of the holder 24, out of both ends of the rotating shaft 211 of the payout roller 21 that is rotatably supported by the holder 24.

When the rotary shaft 211 of the delivery roller 21 rotates in the direction of the arrow 96b shown in FIG. 4 (when the drive motor 251 rotates forward), the one-way clutch 69 transmits the rotational force of the rotary shaft 211 to the plate cam 63 (ON), and when the rotary shaft 211 rotates in the direction of the arrow 95b shown in FIG. 4 (when the drive motor 251 rotates backward), the one-way clutch 69 does not transmit the rotational force of the rotary shaft 211 to the plate cam 63 (OFF). Note that as long as it transmits the rotational drive force in only one direction, it is not limited to a one-way clutch, and for example, a one-way bearing or a ratchet mechanism can also be used.

The plate cam 63 is made of a resin such as PE, but is not limited to this and may be made of a metal such as iron.
[5] Description of the Operation of Locking Holder 24 by Locking Unit 29 and Unlocking Holder 24 by Unlocking Unit 60 FIG. 8 is a schematic rear view showing the state in which holder 24 is raised from the first position by reverse rotation of drive motor 251.

As shown in the figure, the payout roller 21 is raised higher than the payout position shown in FIG. 5, the upper end 511 of the locking projection 51 enters the inner space 528 of the compression coil spring 52, and the inclined surface 515 of the claw portion 512 contacts the inner peripheral surface of the winding 525 while the upper surface 244 of the base 243 of the holder 24 pushes up the lower end 522 of the compression coil spring 52, compressing and deforming the compression coil spring 52. This compressive deformation of the compression coil spring 52 absorbs the impact energy between the holder 24 and the wall body 98 via the compression coil spring 52, thereby reducing the impact noise.

When the holder 24 is rising, the one-way clutch 69 built into the plate cam 63 is turned off due to the reverse rotation of the payout roller 21, so the rotational force of the rotating shaft 211 of the payout roller 21 is not transmitted to the plate cam 63, and the plate cam 63 appears to slide in the counterclockwise direction in the figure relative to the rotating shaft 211 of the payout roller 21. Therefore, even if the tip 61 of the plate cam 63 (the part radially farthest from the rotating shaft 211) hits the lower end 522 of the compression coil spring 52, the plate cam 63 does not apply a force pushing up from below to the compression coil spring 52.

FIG. 8 shows the movement trajectory 249 (dash line) of the rotation shaft 211 of the delivery roller 21 when the holder 24 swings up and down around the rotation shaft 221 of the paper feed roller 22. As shown in the figure, the movement trajectory 249 is separated from the compression coil spring 52, so that the rotation shaft 211 of the delivery roller 21 does not contact the compression coil spring 52, and the size of the plate cam 63 and the positional relationship of the rotation shaft 211 of the delivery roller 21 with respect to the compression coil spring 52 are predetermined so that only the tip 61 of the plate cam 63 contacts the compression coil spring 52.

Figure 9 is a schematic rear view showing the state when the holder 24 is raised further than the position shown in Figure 8, and the amount of deformation of the compression coil spring 52 is greater than that shown in Figure 8. The locking protrusion 51 is inclined slightly to the right with respect to the vertical direction.

The greater the amount of compression deformation of the compression coil spring 52, the greater the restoring force P of the compression coil spring 52 according to Hooke's law. The greater the restoring force P of the compression coil spring 52, the greater the force pushing the holder 24 downward, i.e., the greater the moment M that tries to rotate the holder 24 downward around the rotation axis 221 of the paper feed roller 22.

When the holder 24 is rising, a rotational driving force Q from the drive motor 251, which rotates in the reverse direction, acts on the rotating shaft 221 of the paper feed roller 22, and at the same time, a moment M due to the restoring force P of the compression coil spring 52 acts on the holder 24 in opposition to this rotational driving force Q. Note that the rotational driving force Q reaches a maximum constant value when the torque limiter 255 starts to slip as described above.

When the moment M acting on the holder 24 is sufficiently smaller than the rotational driving force Q from the drive motor 251, that is, when the amount of compressive deformation of the compression coil spring 52 is small as shown in Figure 8, the compression coil spring 52 is pushed up by the holder 24, causing further compressive deformation.

When the amount of compressive deformation increases and the restoring force P of the compression coil spring 52 increases, and the moment M acting on the holder 24 balances with the rotational driving force Q (maximum value mentioned above) from the drive motor 251, the holder 24 stops rising while the rotation shaft 221 of the paper feed roller 22 continues, and the holder 24 comes to a standstill in the position shown in FIG. 9. At this time, the spring constant of the compression coil spring 52 is predetermined so that the windings 525 are not in close contact with each other.

Although the tip 61 of the plate cam 63 is in contact with the outer peripheral surface of the winding 525, the plate cam 63 does not exert any upward force on the compression coil spring 52 as described above.

Next, when at least one of the drive motor 251 and the electromagnetic clutch 253 is turned off (hereinafter referred to as "driving stopped"), the rotational drive force Q becomes zero, so that the holder 24 is subjected to the restoring force P of the compression coil spring 52 and a downward force due to its own weight, and the holder 24 tries to descend. At this time, as shown in FIG. 10, the claw portion 512 of the locking projection 51 hooks onto a part 529 of the winding 525 of the compression coil spring 52. Specifically, the part 529 of the winding 525 enters the inner hooking surface 517 from the tip of the claw portion 512. This part 529 of the winding 525 becomes a part (locked part) in the vertical direction of the compression coil spring 52 that is locked onto the locking projection 51.

The locking projection 51 protrudes from the base 243 of the holder 24, so that when the claw portion 512 of the locking projection 51 catches on the winding 525, the holder 24 hangs from a part 529 of the compression coil spring 52 via the claw portion 512 of the locking projection 51. This hanging prevents the holder 24 from falling (locking the holder 24), and the holder 24 is maintained stationary in the second position.

After the drive is stopped, the drive motor 251 starts rotating forward while the electromagnetic clutch 253 is turned on (hereinafter referred to as "starting forward drive"), and as shown in FIG. 11, the feed roller 22 and the delivery roller 21 start rotating forward (in the direction of arrows 96 and 96b). The forward rotation of the delivery roller 21 turns on the one-way clutch 69 built into the plate cam 63, and the rotational force of the rotating shaft 211 of the delivery roller 21 is transmitted to the plate cam 63. As a result, the plate cam 63 starts rotating (forward rotation) together with the rotating shaft 211 in the same direction.

When the plate cam 63 rotates, the peripheral surface 62 (Figure 7) of the tip 61 of the plate cam 63 comes into contact with the winding 525 of the compression coil spring 52, forcing the lower end 522 side of the compression coil spring 52 relative to its upper end 521 in a direction away from the plate cam 63 (to the left in the figure), causing it to bend.

This disengages the hook portion 512 of the locking projection 51 from the winding 525 (unlocking). The shape and size of the hook portion 512 and the radial length of the plate cam 63 are determined in advance so that this unhooking operation can be performed reliably. In this sense, the plate cam 63 functions as a pressing member that applies a pressing force to the winding 525 in a direction to disengage the hook portion 512 of the locking projection 51 from the winding 525, and it can be said that the plate cam 63 built into the one-way clutch 69, as well as the rotating shaft 211 of the payout roller 21, the driving force transmission mechanisms 25, 26, and the drive motor 251 constitute the unlocking unit 60.

When the claw portion 512 of the locking projection 51 is released from the winding 525, the weight of the holder 24 and the rotational driving force of the drive motor 251 rotating forward move the holder 24 from the second position to the first position, which is lower than the second position. This causes the feed roller 21 to descend, enabling the document to be fed.

As described above, in this embodiment, the compression coil spring 52 serves both to absorb the collision energy with the holder 24 during its ascent (buffer function) and to lock the holder 24 when the application of the rotational driving force is stopped after the holder 24 has been ascent (lock function).

This makes it possible to reduce the noise of collisions with the holder while using fewer parts than conventional configurations, i.e., configurations that use cushioning material to absorb collision energy and three components to lock the holder: a protrusion, an engaging member that engages with the protrusion, and a spring.
<Embodiment 2>
In the above-mentioned embodiment 1, a configuration example was described in which the locking projection 51 protruding from the holder 24 enters the inner space 528 of the compression coil spring 52 and the claw portion 512 of the locking projection 51 hooks onto the winding 525, but in this respect, the embodiment 2 is different from the embodiment 1 in that the locking projection 51 hooks onto the winding 525 from the outside of the compression coil spring 52. In the following, in order to avoid duplication, the description of the same contents as in the embodiment 1 will be omitted, and the same reference numerals will be used for the same components.

Figure 12 is a schematic rear view for explaining an example of the configuration of the locking protrusion 51 according to embodiment 2, Figure 13(a) is a schematic perspective view of the locking protrusion 51 shown in Figure 12, and Figure 13(b) is a schematic plan view of the locking protrusion 51 shown in Figure 12. Note that Figures 12, 13(a), and (b) show an example in which the payout roller 21 is in the payout position and the holder 24 is in the first position.

As shown in Figures 12, 13(a) and 13(b), the locking projection 51 has a base end 510 that is erected on the base 243 of the holder 24 and an upper end 511 that is continuous with the base end 510. A claw portion 512 is provided on the surface of the upper end 511 on the side where the plate cam 63 is located, and a bent piece 518 that is L-shaped in a plan view is provided on the surface facing the back surface 242 of the holder 24.

The positional relationship between the locking projection 51 and the compression coil spring 52 in the X-axis direction is such that when the holder 24 shown in FIG. 12 is raised, the locking projection 51 is located on the side of the compression coil spring 52 in the X direction (left side), and as the holder 24 is raised, the compression coil spring 52 is compressed and deformed, and the claw portion 512 of the locking projection 51 presses the winding 525 of the compressed and deformed compression coil spring 52 from the outer periphery toward the inner periphery by an amount corresponding to the inclination angle of the inclined surface 515, so that the locking projection 51 moves upward while deforming the winding 525 in the pressing direction, and the claw portion 512 of the locking projection 51 hooks onto the winding 525 after the drive is stopped.

The bent piece 518 of the locking projection 51 is located above the base 243 of the holder 24 and has a first portion 581 that extends from the upper end 511 of the locking projection 51 toward the back surface 242 of the holder 24, and a second portion 582 that is bent at a right angle from the tip of the first portion 581 in the direction where the plate cam 63 is located.

As shown in FIG. 13(b), the second portion 582 is closer to the rear surface 242 of the holder 24 than the compression coil spring 52 and does not come into contact with the compression coil spring 52.

The second portion 582 has the same positional relationship in the Z-axis direction as the plate cam 63 fitted on the rotating shaft 21a of the pay-out roller 21, and has a positional relationship in which the tip 61 of the plate cam 63 and the tip 585 of the second portion 582 overlap when the plate cam 63 is in the angular position shown in FIG. 12 in a plan view. The reason for this positional relationship is that when the plate cam 63 rotates forward integrally with the rotating shaft 211 of the pay-out roller 21 as described below, the peripheral surface 62 of the tip 61 of the plate cam 63 presses the second portion 582 of the locking projection 51, bending the locking projection 51 in the direction of the arrow X, thereby releasing (unlocking) the claw portion 512 of the locking projection 51 from the winding wire 525.

Below, the lifting, locking, and unlocking of the holder 24 are explained in detail with reference to Figures 14 to 16.

Figure 14 is a schematic rear view showing the state in which the holder 24 rises from the first position and the compression coil spring 52 is pressed and compressed by the holder 24.

As shown in the figure, when the locking projection 51 rises together with the holder 24, the inclined surface 515 of the claw portion 512 of the locking projection 51 comes into contact with the outer surface of the winding 525 from the outside of the coil portion 520 of the coil spring 52, while the upper surface 244 of the base 243 of the holder 24 pushes up the lower end portion 522 of the compression coil spring 52, compressing and deforming the compression coil spring 52.

As in the first embodiment, while the holder 24 is rising, the plate cam 63 slides against the rotary shaft 211 of the payout roller 21 due to the action of the one-way clutch 69 built into the plate cam 63. Therefore, even if the peripheral surface of the tip 61 of the plate cam 63 hits the second part 582 of the bent piece 518 of the locking projection 51 while the holder 24 is rising, no force is applied to bend the locking projection 51, and the plate cam 63 hits the lower end of the second part 582 of the bent piece 518 and comes to a stationary state.

Figure 15 is a schematic rear view showing the state when the holder 24 is stopped after rising further than the position shown in Figure 14, and the claw portion 512 of the locking projection 51 is caught by a part 529 of the winding 525 from the outside of the compression coil spring 52. As a result, the holder 24 is suspended from the compression coil spring 52 via the claw portion 512 of the locking projection 51, and the holder 24 is locked in the second position. This part 529 of the winding 525 becomes a part (locked portion) in the vertical direction of the compression coil spring 52 that is locked by the locking projection 51.

Figure 16 is a schematic rear view showing how the feed roller 22 and the delivery roller 21 start rotating in the forward direction (in the direction of arrows 96 and 96b) as a result of forward drive being started after driving has stopped. As the rotating shaft 211 of the delivery roller 21 rotates in the forward direction, the one-way clutch 69 built into the plate cam 63 turns on, and the plate cam 63 starts rotating in the same direction as the rotating shaft 211 of the delivery roller 21.

When the plate cam 63 rotates in the direction of the arrow 96b, the peripheral surface of the tip 61 of the plate cam 63 hits the tip 585 of the second part 582 of the locking projection 51, and the second part 582 is pressed in the direction of the arrow X. This pressing causes the upper end 511 of the locking projection 51, which is connected to the second part 582, to bend elastically relative to the base end 510 in the pressing direction, i.e., in a direction perpendicular to the protruding direction of the locking projection 51, by an amount of eccentricity corresponding to the rotation angle of the plate cam 63, and the claw portion 512 of the locking projection 51 separates from the winding 525 of the compression coil spring 52, and the lock by the locking projection 51 is released.

The locking protrusion 51 is made of a material that is flexible and can bend elastically, such as a resin such as PP (polypropylene) or PE, or a metal.

When the claw portion 512 of the locking projection 51 disengages from the winding 525, the holder 24 descends from the second position to the first position, which is lower than the second position, just like in the first embodiment.

In this manner, in the second embodiment, the claw portion 512 of the locking projection 51 hooks onto the winding 525 from the outside of the compression coil spring 52 to lock the holder 24 at a second position higher than the first position after the drive is stopped, and the unlocking mechanism is configured such that the plate cam 63 hits the bent piece 518 of the locking projection 51, not the compression coil spring 52, to deflect the locking projection 51, thereby releasing the hooking of the claw portion 512 of the locking projection 51 with the winding 525 of the compression coil spring 52. By using such a locking mechanism and unlocking mechanism, it is possible to reduce the number of parts while realizing a reduction in the collision noise with the holder, as in the first embodiment.
<Third embodiment>
In the above-mentioned second embodiment, an example configuration was described in which a compression coil spring 52 was used as a cushioning member for absorbing the collision energy with the rising holder 24. However, in the third embodiment, a zigzag-shaped spring 352 (hereinafter referred to as a "zigzag spring") as shown in the schematic oblique view of FIG. 17(a) and the schematic rear view of FIG. 17(b) is used instead of the compression coil spring 52, which differs from the second embodiment.

The zigzag spring 352 is made by bending a strip of steel plate in a zigzag shape, with one end (upper end) 321 in the longitudinal direction supported by the wall body 98 and the other end (lower end) 322 being a free end. Each of the multiple bent portions 325 of the zigzag spring 352 is arranged alternately in a zigzag shape from top to bottom in rear view.

When the bends 325 are numbered from top to bottom, starting with the first (highest), second, third, etc., the length between two adjacent bends 325, specifically the first and second, third and fourth, and fifth and sixth, is β (Fig. 17(b)), and the length between the second and third, and fourth and fifth is α (<β), so that the positions in the X-axis direction are the same for two bends that are vertically adjacent, that is, the first and third, second and fourth, etc. In the schematic rear view of Fig. 17(b) below, odd-numbered bends 325 are classified as a first group 325a, and even-numbered bends are classified as a second group 325b.

In such a configuration with a zigzag spring 352, when the holder 24 rises, the inclined surface 515 of the claw portion 512 of the locking projection 51 contacts the multiple bent portions 325 belonging to the first group 325a of the zigzag spring 352 in order, starting from the lowest one and moving up one by one, while the upper surface 244 of the base 243 of the holder 24 pushes up the lower end portion 322 of the zigzag spring 352, compressing and deforming the zigzag spring 352.

When the holder 24 continues to rise and then stops driving, as shown in the partial schematic rear view of FIG. 18, the claw portion 512 of the locking projection 51 hooks onto one of the multiple bent portions 325 of the zigzag spring 352 (locking the holder 24), and the holder 24 hangs from the zigzag spring 352 via the claw portion 512 of the locking projection 51. This one bent portion 325 becomes part of the zigzag spring 35 in the vertical direction that is locked onto the locking projection 51.

When forward driving is started after driving is stopped, as shown in FIG. 19, the plate cam 63 starts rotating in the same direction as the rotating shaft 211 of the payout roller 21, and the peripheral surface of the tip 61 of the plate cam 63 presses the tip 585 of the second part 582 of the locking protrusion 51 in the direction of the arrow X, bending the locking protrusion 51 and disengaging the claw portion 512 of the locking protrusion 51 from the bent portion 325 of the zigzag spring 352. This releases the lock provided by the locking protrusion 51. This unlocking mechanism is basically the same as in embodiment 2.

In this manner, the configuration of embodiment 3 using the zigzag spring 352 can reduce the number of parts while reducing the impact noise with the holder, just like embodiment 2.

The zigzag spring 352 is a type of leaf spring, which is made by bending a strip of steel plate in a zigzag shape, and can be considered to have a larger spring constant than a coil spring made of a linear member wound in a spiral shape. A larger spring constant can absorb more collision energy with the holder 24 when the amount of compressive deformation is the same, rather than a smaller one. The collision energy with the holder 24 increases as the kinetic energy of the holder 24 rises. The kinetic energy of the holder 24 during the rise increases as the total mass of the holder 24, including the delivery roller 21 and the paper feed roller 22, increases compared to a lighter mass, and also increases as the rising speed increases. For these reasons, when there is a certain limit to the space for arranging the spring, and the total mass of the holder 24 is large or the rising speed is fast, the zigzag spring 352 can be used to expand the design freedom and realize a more suitable device configuration.

The zigzag spring 352 can be manufactured by a processing method such as pressing, electric casting, etc. The zigzag spring 352 is not limited to being made of a steel plate, and may be made of other metal materials or resin such as PE.
<Modification>
While the present disclosure has been described above based on the embodiments, it goes without saying that the present disclosure is not limited to the above-described embodiments, and the following modified examples are possible.

[1] In the above embodiment 1, a compression coil spring 52 is used as a cushioning member that absorbs the collision energy with the rising holder 24, but this is not limited to this, and springs of other shapes, such as conical coil springs, can also be used.

When a conical coil spring is used, the upper end 521 is supported on the wall 98 in such a position that the lower end 522 of the conical coil spring has a larger inner diameter than the upper end 521. The lower end 522 of the conical coil spring is a free end.

When a conical coil spring is used, as in the first embodiment, the claw portion 512 of the locking projection 51 erected on the base 243 of the holder 24 hooks onto the winding 525 of the conical coil spring from the inside of the conical coil spring, thereby locking the holder 24. The lock is also released by rotating the plate cam 63, as in the first embodiment.

When a conical coil spring is used, the lower end 522 has a larger inner diameter than the upper end 521, so that when the locking projection 51 begins to enter the inner space of the conical coil spring as the holder 24 rises, the claw portion 512 of the locking projection 51 does not come into contact with the windings of the lower end 522 of the conical coil spring, but instead comes into contact with the windings in the middle of the conical coil spring during the rise.

In such a configuration, instead of providing an inclined surface 515 on the outside of the claw portion 512, the shape of the claw portion 512 of the locking projection 51 can be, for example, such that the upper end portion 511 of the locking projection 51 is bent at a right angle to the base end portion 510, and the bent portion serves as the claw portion 512. This is because, in cases where the drive is stopped after the claw portion of the locking projection 51 hits the winding in the middle portion of the conical coil spring, the locking projection 51 can rise smoothly relative to the conical coil spring even without providing an inclined surface 515, and the right-angled bent portion can catch on the winding in the middle portion, thereby locking the holder 24.

In addition, instead of using a spring such as the compression coil spring 52 or the zigzag spring 352 as the cushioning member, for example, in the second and third embodiments, instead of the compression coil spring 52 and the zigzag spring 352, a cylindrical or cylindrical sponge body made of a material capable of elastic compression deformation, such as soft urethane foam, can be arranged.

The upper end of the sponge body is supported by the wall body 98, and the lower end is a free end. This is the same as the compression coil spring 52 and the zigzag spring 352. Since the sponge body does not have windings or bent parts like a spring, a latching part for the claw part 512 of the latching projection 51 to catch on, for example a recess on the outer circumferential surface of the sponge body, is provided in advance. This recess becomes the part of the sponge body in the vertical direction (the latching part) that latches onto the latching projection 51.

In this configuration, when the holder 24 rises, the claw portion 512 of the locking projection 51 moves upward relative to the sponge body so as to slide on the outer circumferential surface of the sponge body. When the drive is stopped, the claw portion 512 of the locking projection 51 gets caught in a recess provided on the outer circumferential surface of the compressed and deformed sponge body. This causes the holder 24 to hang from the sponge body, completing the locking. The lock is released by the cam 60 pressing the bent piece 518 of the locking projection 51 to bend the locking projection 51, as in the second and third embodiments. The material is not limited to the sponge body, and other materials can be used as long as they have both the functions of cushioning and locking.

In this way, it is possible to use compressible and deformable materials other than springs as the cushioning material, expanding the options for materials to be used as cushioning materials, allowing cushioning materials made of materials more suitable for the device configuration to be arranged.

[2] In the above embodiment 1, the locking projection 51 protrudes from the base 243 of the holder 24, and the compression coil spring 52 is supported on the wall 98, i.e., the locking projection 51 is provided on the rising holder 24 (moving side), and the compression coil spring 52 is provided on the wall 98 of the device body 95 on the non-moving side (fixed side). However, this is not limited to this. For example, a configuration example in which the compression coil spring 52 is provided on the moving holder 24, and the locking projection 51 is provided on the fixed device body may also be used.

Figure 20(a) is a schematic rear view showing the configuration of this modified example, Figure 20(b) is a schematic enlarged perspective view of the locking projection 51 of this modified example, and Figure 20(c) is a schematic diagram showing the positional relationship between the locking projection 51, compression coil spring 52, and cam 60 when the locking projection 51 is viewed from the direction of arrow W shown in Figure 20(a).

As shown in FIG. 20(a), the lower end 522 of the compression coil spring 52 is supported on the base 243 of the holder 24, the upper end 521 of the compression coil spring 52 is a free end, and a locking projection 51 protrudes downward from the lower surface 99 of the wall body 98.

As shown in FIG. 20(b), the locking projection 51 has a base end 510, a lower end 511 provided with a claw portion 512, and an L-shaped bent piece 718 provided on the lower end 511.

The claw portion 512 is hook-shaped, and has an inclined surface 515 on its outside that slopes downward from the tip of the hook toward the base end (rear end), and a hooking surface 517 on its inside.

The bent piece 718 is located below the wall body 98, and has a first portion 581 extending from the lower end 511 of the locking projection 51 toward the back surface 242 of the holder 24 as shown in Figs. 20(b) and (c), and a second portion 582 bent at a right angle from the tip of the first portion 581 toward the position of the plate cam 63. The second portion 582 is closer to the back surface 242 of the holder 24 than the compression coil spring 52, and does not contact the compression coil spring 52. The bent piece 718 has the same function as the bent piece 518 in the second embodiment, that is, it is used to bend the locking projection 51 when pressed by the plate cam 63 during unlocking.

In this configuration, when the holder 24 rises, the compression coil spring 52 also rises together with the holder 24. This rise causes the inclined surface 515 of the claw portion 512 of the locking projection 51 to slide from the outside of the coil portion 520 of the coil spring 52 while in contact with the outer surface of the winding 525. When the upper end portion 521 of the coil spring 52 then hits the wall 98, the rise of the upper end portion 521 of the coil spring 52 stops and the base 243 of the holder 24 pushes up the lower end portion 522 of the compression coil spring 52, compressing and deforming the compression coil spring 52. This compressive deformation absorbs the impact energy between the holder 24 and the wall 98 via the compression coil spring 52.

Figure 21 is a schematic partial rear view showing only the locking projection 51 and its surroundings when the holder 24 is further raised and then stopped. As shown in the figure, the claw portion 512 of the locking projection 51 hooks onto a part 529 (locked portion) of the winding 525 from the outside of the compression coil spring 52. This causes the holder 24 to hang from the wall 98 via the compression coil spring 52 and the locking projection 51, and the holder 24 is locked in the second position.

The lock is released by the peripheral surface of the cam 60 pressing against the bent piece 718 of the locking projection 51, bending the locking projection 51, as in the second embodiment.

As with the embodiment, the configuration of this modified example can reduce the number of parts while reducing the impact noise that occurs when the holder 24 is raised.

It may also be possible to adopt another modified configuration in which the compression coil spring 52 in this modified example is replaced with the zigzag spring 352 or sponge body described above.

[3] In the above embodiment, a configuration example in which the holder 24 is supported so as to be freely swingable up and down around the rotation axis 221 of the paper feed roller 22 has been described, but any support mechanism that supports the holder 24 so as to be freely movable up and down relative to the tray 1 may be used. For example, a support mechanism that supports the holder 24 so as to be freely slidable up and down as a whole may be used. When this support mechanism is used, the drive unit 25 is configured to move up and down together with the holder 24, and the holder 24 can be slid upward from the first position by an upward driving force from another drive source, and locked at the second position. The lock can be released by rotating the feed roller 21 forward by rotating the drive motor 251 of the drive unit 25 forward, as in the first embodiment. When the lock is released, the holder 24 and the drive unit 25 slide downward under their own weight, and the holder 24 can be configured to descend from the second position to the first position.

[4] In the above embodiment 1, the plate cam 63 applies a pressing force to the winding 525 of the compression coil spring 52 to deflect the winding 525, and in the embodiment 2, the plate cam 63 applies a pressing force to the locking protrusion 51 to deflect the locking protrusion 51. However, the pressing member that applies the pressing force to the pressing object (winding 525 or locking protrusion 51) is not limited to the plate cam 63. For example, a configuration can be adopted in which an electric actuator such as a solenoid is used in addition to the plate cam 63, and the driving force of the solenoid is applied as a pressing force to the pressing object. In this configuration, the electric actuator is turned on (operated) when the holder 24 is lowered from the second position to the first position.

[5] In the above embodiment, a configuration example has been described in which the sheet feeding section 2 (sheet feeding device) according to the present disclosure is provided in the document transport device 111 (sheet transport device) in the image reading device of an MFP, but this is not limited to this, and the sheet feeding section 2 (sheet feeding device) may be provided in a document transport device or image reading device included in an image forming device such as a copier or facsimile machine. The image reading device is not limited to a configuration that is part of the image forming device, but may be a device dedicated to image reading, such as a scanner that reads images of a document, and the scanner may be provided with the sheet feeding device according to the present disclosure or a sheet transport device equipped with the same.

Furthermore, the sheet feeding device or the sheet transport device equipped with the same is not limited to a configuration in which it is provided in an image reading device, but can also be used in a sheet feeding device or a sheet transport device equipped with the same that feeds paper one sheet at a time from a stack of paper placed on a tray (not shown) of each of paper feed cassettes 121 to 124 (Figure 1) and feeds the paper to a transport path of image forming device 102.

Furthermore, the shapes, sizes, numbers, materials, etc. of each component, including the above-mentioned locking protrusions 51 and plate cams 63, are not limited to those described above, and shapes, etc. suitable for the device configuration can be used.

The configurations of the above embodiments and modifications may be combined as much as possible.

This disclosure can be widely applied to sheet feeding devices that feed sheets on a tray and image reading devices equipped with the same.

REFERENCE SIGNS LIST 1 document tray 2 sheet delivery section 21 delivery roller 22 paper feed roller 24 holder 25, 26 driving force transmission mechanism 29 lock section 51 engagement protrusion 52 compression coil spring 60 lock release section 61 tip of plate cam 62 peripheral surface of plate cam 63 plate cam 69 one-way clutch 98 wall 101 image reading device 111 document transport device 243 base 251 drive motor 325 bent section of zigzag spring 352 zigzag spring 512 claw section 515 outer inclined surface of claw section 517 inner hook surface of claw section 518, 718 bent piece 525 winding 529 part of winding

Claims (14)

A sheet feeding device that feeds a sheet on a tray by a roller,
A holder that rotatably supports the roller;
A support portion that supports the holder so as to be movable up and down;
A drive unit that lifts the holder;
A wall located above the holder;
The holder is located below the wall body, and includes a locking member provided on one of the holder and the wall body, and a buffer member provided on the other of the holder and the wall body.
This sheet dispensing device is characterized in that the buffer member is pushed by the rising holder and compressed and deformed between the holder and the wall, and after the drive is stopped, a locking member locks into a portion of the buffer member in the vertical direction, causing the raised holder to hang from the wall via the locking member. The buffer member is a compression coil spring,
The locking member has a claw portion,
a portion of the buffer member is a portion of a coil of a compression spring;
2. The sheet delivery device according to claim 1, wherein after the drive is stopped, the claw portion is caught on a part of the winding, so that the holder is in the hanging state. The locking member is provided to protrude from the holder,
The compression coil spring has an axial upper end supported by the lower surface of the wall and a lower end that is a free end.
The claw portion is hook-shaped, and has an inclined surface on the outside thereof that rises from the tip end toward the base end, and has a hooking surface on the inside thereof for hooking a part of the winding wire,
During the elevation of the holder, the lower end of the compression coil spring is pushed up by the holder, and the compression coil spring is compressed and deformed, while the claw portion enters the inner space of the deformed compression coil spring, and the inclined surface of the claw portion pushes the winding from the inner periphery side to the outer periphery side by an amount corresponding to the inclination angle, thereby moving upward while deforming the winding in the pressing direction as well,
3. The sheet dispensing device according to claim 2, wherein after the driving is stopped, a part of the winding wire enters the hooking surface from the tip of the claw portion, thereby causing the claw portion to hook onto the winding wire. The locking member is provided to protrude from the holder,
The compression coil spring has an axial upper end supported by the lower surface of the wall body and a lower end serving as a free end.
The claw portion is hook-shaped, and has an inclined surface on the outside thereof that rises from the tip end toward the base end, and has a hooking surface on the inside thereof for hooking a part of the winding wire,
During the elevation of the holder, the lower end of the compression coil spring is pushed up by the holder, compressing and deforming the compression coil spring, and the claw portion moves upward while deforming the coil of the deformed compression coil spring in the pressing direction as well by pushing the inclined surfaces of the claw portion from the outside toward the inner periphery by an amount corresponding to the inclination angle of the inclined surfaces of the claw portion,
3. The sheet dispensing device according to claim 2, wherein after the driving is stopped, a part of the winding wire enters the hooking surface from the tip of the claw portion, thereby causing the claw portion to hook onto the winding wire. The locking member is provided on the lower surface of the wall body,
The compression coil spring has a lower end supported by the holder in the axial direction and an upper end serving as a free end,
The claw portion is hook-shaped, and has an inclined surface on the outside thereof that slopes downward from the tip end toward the base end, and has a hooking surface on the inside thereof for hooking a part of the winding wire,
During the upward movement of the holder, the upper end of the compression coil spring comes into contact with a wall and stops, and the lower end is pressed by the holder, thereby undergoing compressive deformation. Meanwhile, the inclined surfaces of the claw portions press the coil of the deformed compression coil spring from the outside toward the inner periphery by an amount corresponding to the inclination angle, so that the coil moves upward while being deformed in the pressing direction as well.
3. The sheet dispensing device according to claim 2, wherein after the driving is stopped, a part of the winding wire enters the hooking surface from the tip of the claw portion, thereby causing the claw portion to hook onto the winding wire. The sheet dispensing device according to any one of claims 3 to 5, characterized in that the compression coil spring is a cylindrical coil spring. The buffer member is a zigzag spring,
The locking member has a claw portion,
the part of the buffer member is one of a plurality of bent portions of the zigzag spring,
2. The sheet delivery device according to claim 1, wherein after the drive is stopped, the claw portion is caught on one of the bent portions of the zigzag spring, so that the holder is in the hanging state. The sheet delivery device according to claim 1, 2 or 7, further comprising a release unit that releases the lock. A release unit that releases the lock is further provided,
The release unit is
The sheet dispensing device according to claim 3, further comprising a pressing member that applies a pressing force to the winding of the compression coil spring in a direction to release the winding when a portion of the winding is caught on the claw portion, thereby releasing the winding. A release unit that releases the lock is further provided,
The locking member has flexibility such that a tip side in a protruding direction is elastically bent in a direction perpendicular to the protruding direction relative to a base end portion thereof,
The release unit is
The sheet dispensing device according to claim 4, further comprising a pressing member which applies a pressing force to the locking member in a direction to release the hook when a portion of the winding wire is caught on the claw portion, thereby bending the locking member and releasing the hook. the drive unit includes a transmission mechanism that applies a rotational drive force to the rotation shaft of the roller after the holder is suspended after driving of the holder is stopped,
The sheet dispensing device according to claim 9 or 10, characterized in that the pressing member is a cam provided on the rotation shaft of the roller and rotates integrally with the rotation shaft of the roller, and the pressing force is applied to the pressing object by the peripheral surface of the cam. When the roller is a delivery roller, the sheet conveying device further includes a paper feed roller located downstream of the delivery roller in a sheet conveying direction,
the holder rotatably supports the delivery roller and the paper feed roller;
the drive unit is capable of switching between applying a drive force for a forward rotation during sheet transport and a drive force for a reverse rotation opposite thereto to the delivery roller and the paper feed roller via the transmission mechanism,
the support section supports the holder so that the side on which the delivery roller is supported can be swung up and down around the rotation axis of the paper feed roller and can freely move, and supports the holder so that a force in a downward direction is applied to the holder when a driving force for the forward rotation is applied, and a force in a upward direction is applied to the holder when a driving force for the reverse rotation is applied,
The cam is connected to the rotary shaft of the delivery roller via a one-way clutch,
the one-way clutch is a clutch that transmits a driving force to the cam when a driving force for the forward rotation is applied to the rotating shaft of the delivery roller, and does not transmit the driving force to the cam when a driving force for the reverse rotation is applied,
The sheet dispensing device according to claim 11, characterized in that, when the lock is released, the driving force for the forward rotation is transmitted from the drive unit to the cam via the transmission mechanism, the rotating shaft of the dispensing roller, and the one-way clutch. A sheet conveying device comprising the sheet feeding device according to any one of claims 1 to 12, and conveying a sheet fed by the sheet feeding device. An image reading apparatus for obtaining image data by reading an image on a sheet conveyed by a sheet conveying unit,
An image reading apparatus comprising the sheet transport device according to claim 13 as the sheet transport section.

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