JP2020193060A - Drive coupling device - Google Patents

Abstract

To provide a drive transmission device capable of transmitting a driving force of a drive wheel body to a driven wheel body with high accuracy.SOLUTION: A drive wheel body and an intermediate wheel body are in close contact with each other at the initial rotation phase. The intermediate wheel body is kept rotatable against the drive wheel body until the drive wheel body rotates by a fixed angle. The intermediate wheel body is pressed in the axial direction to approach a driven wheel body by a motion direction conversion mechanism provided between the intermediate wheel body and the drive wheel body and when it exceeds a fixed angle, the motion direction conversion mechanism stops a conversion function, the drive body and the intermediate wheel body are coupled and a rotational force of the drive wheel body is transmitted to the intermediate wheel body. Between the intermediate wheel body and the drive wheel body, a one-way clutch mechanism is provided for the intermediate wheel body to function in a close-contact with the driven wheel body. A restraint member, which restrains the intermediate wheel body from being co-rotated by the drive wheel body before the intermediate wheel body comes into close-contact with the driven wheel body, is provided under an abutment state onto the intermediate wheel body.SELECTED DRAWING: Figure 3

Description

The present invention relates to a drive coupling device for transmitting the driving force of a driving source to a roller that conveys paper.

An image forming apparatus such as a copier is provided with a conveying mechanism that feeds out documents or papers set in a paper feed tray one by one, conveys them to an image reading position or an image forming position, and then ejects them onto an output tray. ..

For example, in Patent Document 1, the documents set in the paper feed tray are fed one by one to the transport path by the paper feed roller, the direction is adjusted by the resist roller, and then the documents are transported to the reading position to read the document surface. The configuration to be performed is disclosed. When the tip of the document conveyed in the transfer path is started to be conveyed by the resist roller, the transmission of the driving force from the drive source (motor) to the paper feed roller is cut off, and the paper feed roller is moved to the next document. Prepare for paper feeding. At this time, since the paper feed roller is connected to the drive source via the one-way clutch, the paper feed roller is driven to rotate by transporting the paper feed until the rear end of the document passes through the paper feed roller. Therefore, it is possible to transport the original without imposing a burden on the original.

Japanese Unexamined Patent Publication No. 2013-11812

As a one-way clutch that connects the paper feed roller and the drive source, consider the one-way clutch shown in FIG.

This one-way clutch is rotatable with respect to a rotary shaft 1501 that rotates based on a driving force input from a drive source, a drive wheel body 1502 that is fixed to the rotary shaft 1501 and rotates integrally with the rotary shaft 1501, and a rotary shaft 1501. A cylindrical intermediate wheel body 1503 inserted into the machine, and a driven wheel body 1504 that is rotatably inserted into the rotating shaft 1501 and is fixed to the paper feed roller 1505 and rotates integrally with the paper feed roller 1505. To be equipped. On the surface of the drive wheel body 1502 facing the intermediate wheel body 1503, a convex portion 1502a is provided on the peripheral edge portion. On the surface of the intermediate wheel body 1503 facing the drive wheel body 1502, a recess 1503a for receiving the convex portion 1502a is provided on the peripheral edge portion. A part of the bottom surface of the recess 1503a is an inclined surface 1503b inclined in the direction of the drive wheel body 1502. One side surface of the recess 1503a is a contact surface 1503c parallel to the axial direction of the rotating shaft 1501. On the surface of the intermediate wheel body 1503 facing the driven wheel body 1504, a claw portion 1503d is provided on the peripheral edge portion. On the surface of the driven wheel body 1504 facing the intermediate wheel body, a claw portion 1504a capable of meshing with the claw portion 1503d is provided on the peripheral edge portion.

Here, when the rotation shaft 1501 rotates in the forward direction (counterclockwise when viewed from right to left in FIG. 10), the drive wheel body 1502 also rotates in the forward direction, and the convex portion 1502a moves in the G direction in the figure. To do. Then, the convex portion 1502a abuts on the inclined surface 1503b, a component force in the G direction corresponding to the inclination of the inclined surface 1503b of the driving force of the driving wheel body 1502 acts on the intermediate wheel body 1503, and the intermediate wheel body 1503 is in the H direction. Slide to. By this slide, the claw portion 1503d of the intermediate wheel body 1503 and the claw portion 1504a of the driven wheel body 1504 mesh with each other, and the intermediate wheel body 1503 and the driven wheel body 1504 are connected. In this state, the convex portion 1502a of the drive wheel body 1502 comes into contact with the contact surface 1503c of the concave portion of the intermediate wheel body 1503, so that the rotational force of the drive wheel body 1502 passes through the intermediate wheel body 1503 and the driven wheel body 1504. It is transmitted to the paper feed roller 1505.

In such a one-way clutch, rarely, before the intermediate wheel body 1503 and the driven wheel body 1504 are connected, the intermediate wheel body 1503 is brought to the drive wheel body 1502 without moving in the H direction. There is a problem that the driving force of the driving wheel body 1502 is not normally transmitted to the driven wheel body 1504.

The present invention has been made in view of the above problems, and is a drive in which the driving force of the driving wheel body is transmitted to the driven wheel body by connecting the intermediate wheel body and the driven wheel body by sliding the intermediate wheel body. It is an object of the present invention to provide a drive transmission device (clutch) capable of accurately transmitting the driving force of the drive wheel body to the driven wheel body.

The drive coupling device according to one aspect of the present invention includes a drive wheel body connected to a drive source, a driven wheel body coaxially connected to a seat transport roller on the same axis as the drive wheel body, and the driven wheel body. A drive coupling device including an intermediate wheel body slidably provided in the axial direction between the drive wheel body and the driven wheel body, wherein the drive wheel body and the intermediate wheel body are provided. Is close to each other at the initial stage of rotation, and the intermediate wheel body is rotatable with respect to the drive wheel body until the drive wheel body rotates by a certain angle, while the intermediate wheel body and the drive wheel body are movable. The moving direction changing mechanism provided between the and is pushed in the axial direction to approach the driven wheel body, and when a certain angle is exceeded, the moving direction changing mechanism stops the conversion function and the driving wheel. The body and the intermediate wheel body are connected, and the rotational force of the drive wheel body is transmitted to the intermediate wheel body, and the intermediate wheel body is said to be between the intermediate wheel body and the drive wheel body. A one-way clutch mechanism that functions in close contact with the driven wheel is provided, and the intermediate wheel is rotated by the drive wheel before the intermediate wheel is in close contact with the driven wheel. It is characterized in that the restraining member for suppressing the driving is provided in a state of being in contact with the intermediate wheel body.

The motion direction changing mechanism is provided on a convex portion of the drive wheel body facing the intermediate wheel body and a convex portion of the intermediate wheel body facing the drive wheel body to receive the convex portion. The drive wheel is composed of a concave portion, and a part of the bottom surface of the concave portion is inclined in the direction of the intermediate wheel body, and the drive wheel body is rotated in a state of being in contact with the convex portion. It may be an inclined surface that slides the intermediate wheel body in the direction of the driven wheel body by the component force of the driving force of the body.

The restraining member may be made of a conductive material.

The restraining member may be grounded.

According to the present invention, the driving force of the driving wheel body can be accurately transmitted to the driven wheel body.

It is the schematic which shows the structure of the MFP. It is a schematic plan view which shows the structure around the payout roller 32 and the paper feed roller 331 of a paper feed part 3. It is a schematic plan view which shows the paper feed roller 331, the clutch part 505, the rotation shaft 501, and the frame 506 seen from the A direction. It is an exploded perspective view of the clutch part 505. It is a schematic plan view of the clutch part 505. (A) is a schematic view showing a state in which the intermediate wheel body 503 exists in the first position in the clutch portion 505. (B) is a schematic view showing a state in which the intermediate wheel body 503 is sliding from the first position to the second position in the clutch portion 505. (C) is a schematic view showing a state in which the intermediate wheel body 503 exists in the second position in the clutch portion 505. (A) is a schematic view showing a state in which the intermediate wheel body 503 exists in the second position in the clutch portion 505. (B) is a schematic view showing a state in which the intermediate wheel body 503 is sliding from the second position to the first position in the clutch portion 505. (C) is a schematic view showing a state in which the intermediate wheel body 503 exists in the first position in the clutch portion 505. It is a schematic diagram which shows the state that the holding member 507 is grounded. It is a schematic diagram which shows the state that the driven wheel body 504 is grounded. It is a schematic diagram of a conventional one-way clutch.

(Background to the invention)
When the one-way clutch shown in FIG. 10 is considered as the one-way clutch for connecting the paper feed roller and the drive source, as described above, in rare cases, before the intermediate wheel body 1503 and the driven wheel body 1504 are connected, There is a problem that the intermediate wheel body 1503 is rotated around the drive wheel body 1502, and the driving force of the drive wheel body 1502 is not normally transmitted to the driven wheel body 1504.

The inventor examined this problem, and by abutting an elastic body on the intermediate wheel body 1503 and giving rotation resistance to the intermediate wheel body 1503, the rotation of the intermediate wheel body 1503 accompanying the rotation of the drive wheel body 1502 was changed. I considered a configuration to suppress.

When we proceeded with the study on a configuration that suppresses the rotation of the intermediate wheel body 1503 using such an elastic body, static electricity is generated due to friction between the elastic body and the intermediate wheel body 1503, and this static electricity becomes noise to form an image. It has been found that there is a risk of adverse effects such as malfunction of various sensors built in the device.

The inventor further studied, and by forming the elastic body, the intermediate wheel body, and the driven wheel body with a conductive material and grounding them, the adverse effect of static electricity generated by the friction between the elastic body and the intermediate wheel body is suppressed. I found out what I could do.

The inventor has come up with the following embodiments based on the above circumstances.
(Embodiment)
Hereinafter, an embodiment of an image forming apparatus including a double-sided image reading device according to the present invention will be described with reference to the drawings by taking a multifunction device (hereinafter, referred to as “MFP (Multi-Function Peripheral)”) as an example. To do.

<Overall configuration of MFP>
FIG. 1 is a schematic view showing the configuration of the MFP according to the present embodiment.

As shown in the figure, the MFP includes an image reading device 1, an image forming unit 2, a paper feeding unit 3, and a control unit 5.

The image reading device 1 is configured to be capable of reading a document image by a sheet-through method, which is one of fixed optical systems, and a scanner moving method, which is one of moving optical systems. Here, the sheet-through method is a method of reading a document being conveyed (moved) at a fixed reading position while the optical system is stationary (fixed). In the scanner movement method, the mirror that guides the reflected light from the document surface to the scanning sensor is moved with respect to the document while the document is stationary, and the optical path length from the document surface to the scanning sensor is always maintained constant. It is a reading method.

As shown in the figure, the image reading device 1 includes an image reading unit 10 provided with a sheet-through glass 13 and a platen glass 16 on the upper surface thereof, and an automatic document transporting unit (ADF) provided above the image reading unit 10. : Automatic Document Feeder) 40 is provided.

When the image reading unit 10 reads a document by the sheet-through method, when the document transported by the automatic document transporting unit 40 passes over the sheet-through glass 13, the first surface of the document (of the document, The image of the side facing the sheet-through glass 13) is read.

On the other hand, when the original is read by the scanner moving method, the automatic document conveying unit 40 is opened upward by the user, and the original is placed on the platen glass 16 (opposing the original to the platen glass 16). Read the image of the side surface).

When the document image is read by the sheet-through method, the automatic document transport unit 40 transports the documents placed on the document feed tray 40a one by one along the transport path 401 and puts the documents on the sheet-through glass 13. After passing through, it is ejected to the document ejection tray 40b.

Specifically, the document placed on the document feeding tray 40a is fed out to the document transport path 401 by the feed roller 41 and transported to the separation roller pair 42.

The separation roller pair 42 includes a paper feed roller 421 and a handling roller 422 arranged to face each other, and the paper feed roller 421 and the handling roller 422 rotate in opposite directions with each other. , The documents to be conveyed between the paper feed roller 421 and the handling roller 422 are separated one by one and conveyed along the transfer path 401.

The image forming unit 2 forms an image based on the image data read by the image reading device 1, and includes an intermediate transfer belt 22, an image forming unit 23Y, 23M, 23C, 23K, a fixing unit 29, and the like. There is.

The image-creating portions 23Y, 23M, 23C, and 23K are arranged along the intermediate transfer belt 22, and are toner images of yellow (Y), magenta (M), cyan (C), and black (K), respectively. To form. Since the image-creating units 23Y to 23K all have the same configuration, only the image-creating unit 23K will be described, and the description of the other image-creating units 23Y to 23C will be omitted.

The image forming unit 23K includes a photoconductor drum 24K, a charger 25K, an exposure device 26K, a developing device 27K, and a primary transfer roller 28K. The outer peripheral surface of the photoconductor drum 24K is uniformly charged by the charger 25K. The exposure device 26K emits a light beam toward the photoconductor drum 24K by a drive signal based on the image data read by the image reader 1, and exposes and scans the surface of the charged photoconductor drum 24K to expose the photoconductor drum 24K. An electrostatic latent image is formed in.

The electrostatic latent image formed on the outer peripheral surface of the photoconductor drum 24K is developed with toner by the developing device 27K, and the toner image is electrostatically transferred onto the intermediate transfer belt 22 by the primary transfer roller 28K. Color toner images of Y to K are superimposed and transferred onto the intermediate transfer belt 22, and a color toner image is formed.

In parallel with the operation of forming the toner image, the paper feed unit 3 feeds out the paper S one by one from any one of the plurality of paper feed cassettes 31 housed therein, and is provided with the secondary transfer roller 21. Transport to the secondary transfer position.

Specifically, the documents stored in the paper feed cassette 31 are fed out to the document transport path 301 by the feed roller 32 and transported to the separation roller pair 33.

The separation roller pair 33 includes a paper feed roller 331 and a handling roller 332 arranged to face each other, and the paper feed roller 331 and the handling roller 332 rotate in opposite directions to each other. , The documents to be conveyed between the paper feed roller 331 and the handling roller 332 are separated one by one and sent to the transfer roller pair 34.

The transport roller pair 34 is stopped until the tip of the paper S arrives, starts rotating at the timing when the tip of the paper S arrives, and transports the paper S to the secondary transfer roller 21.

At the timing when the transport roller pair 34 rotates, the rotation of the paper feed roller 331 due to the driving force of the drive source is stopped. The paper S is in pressure contact with the paper feed roller 331 until the end of the paper S conveyed by the transfer roller pair 34 passes through the paper feed roller 331, but the paper feed roller 331 accompanies the transfer of the paper S. Since the paper S is driven to rotate, it is possible to transport the paper S by the transfer rollers vs. 34 without imposing a burden on the paper S.

In the paper S, the toner image on the intermediate transfer belt 22 is electrostatically transferred onto the paper S by the secondary transfer roller 21, and the toner image is melted and pressure-bonded to the paper S by heating and pressurizing at the fixing portion 29. After that, it is discharged onto the discharge tray 20a.

The control unit 5 controls the image reading device 1, the image forming unit 2, and the paper feeding unit 3 to execute the feeding of the original when reading the original image and the feeding of the paper S when forming the toner image on the paper S. Let me.

<Structure of clutch unit 505 that connects the paper feed roller 331 and the drive source>
FIG. 2 is a schematic plan view showing the configuration around the feeding roller 32 and the paper feeding roller 331 of the paper feeding unit 3.

The paper feed roller 331 is connected to a rotating shaft 501 that rotates based on a driving force input from a drive source via a clutch portion 505 including a drive wheel body 502, an intermediate wheel body 503, and a driven wheel body 504. There is.

The rotary shaft 501 is rotatably supported by a frame 506 for supporting the feeding roller 32 and the paper feeding roller 331. The drive wheel body 502 is provided so as to be fixed to the rotating shaft 501 and rotate integrally with the rotating shaft 501. The intermediate wheel body 503, the driven wheel body 504, and the paper feed roller 331 are rotatably provided on the rotating shaft 501. The paper feed roller 331 and the driven wheel body 504 are fixed to each other and are provided so as to rotate integrally.

The feeding roller 32 is connected to a rotating shaft 511 that rotates in conjunction with the rotating shaft 501 via a clutch portion 515 including a driving wheel body 512, an intermediate wheel body 513, and a driven wheel body 514.

The rotating shaft 511 is rotatably supported by a frame 506 for supporting the feeding roller 32 and the paper feeding roller 331. The drive wheel body 512 is provided so as to be fixed to the rotating shaft 511 and rotate integrally with the rotating shaft 511. The intermediate wheel body 513, the driven wheel body 514, and the feeding roller 32 are rotatably provided on the rotating shaft 511. The feeding roller 32 and the driven wheel body 514 are fixed to each other and are provided so as to rotate integrally.

Hereinafter, the clutch portion 505 will be described, but the clutch portion 515 also has the same configuration.

FIG. 3 is a schematic plan view showing the paper feed roller 331, the clutch portion 505, the rotating shaft 501, and the frame 506 as viewed from the direction A of FIG. In FIG. 3, only the frame 506 is shown in cross section.

As shown in the figure, a restraining member 507 that imparts rotational resistance to the intermediate wheel 503 is fixed to the frame 506 in order to suppress the rotation of the intermediate wheel 503 accompanying the rotation of the drive wheel 502. Then, the restraining member 507 is in contact with the intermediate wheel body 503 so as to give rotational resistance.

FIG. 4 is an exploded perspective view of the clutch portion 505. The rotary shaft 501 is provided with a through hole 501a through which a pin 501b for connecting the rotary shaft 501 and the drive wheel body 502 is inserted, and the pin 501b is inserted into the through hole 501a.

The drive wheel 502 is provided with a through hole 502b through which the rotating shaft 501 is inserted. The through hole 502b is formed with a groove portion 502c for fixing the pin 501b and transmitting the rotation of the rotating shaft 501 to the drive wheel body 502 via the pin 501b. Further, a convex portion 502a is formed on the peripheral edge of the surface of the drive wheel body 502 facing the intermediate wheel body 503.

The intermediate wheel body 503 is provided with a through hole 503i through which the rotating shaft 501 and the cylindrical portion 504d of the driven wheel body 504 are inserted. A recess 503a that receives the convex portion 502a of the drive wheel body 502 is formed on the peripheral edge of the surface of the intermediate wheel body 503 facing the drive wheel body 502. A claw portion 503f is formed on the peripheral edge of the surface of the intermediate wheel body 503 facing the driven wheel body 504.

The driven wheel body 504 is provided with a through hole 504e through which the rotating shaft 501 is inserted. On the peripheral edge of the surface of the driven wheel body 504 facing the intermediate wheel body 503, a columnar portion 504d inserted into the through hole 503i of the intermediate wheel body 503 and a claw that can mesh with the claw portion 503f of the intermediate wheel body 503. Part 504a is formed.

FIG. 5 is a schematic plan view of the clutch portion 505. As shown in FIG. 5, the bottom surface 503c of the recess 503a of the intermediate wheel body 503 is partially an inclined surface 503d inclined in the direction of the drive wheel body 502. Further, the side surface of the concave portion 503a of the intermediate wheel body 503 is a contact surface 503b and a contact surface 503e that come into contact with the side surface of the convex portion 502a of the drive wheel body 502.

The claw portion 503f of the intermediate ring body 503 is composed of a surface 503g parallel to the axial direction and an inclined surface 503h inclined with respect to the axial direction.

The claw portion 504a of the driven wheel body 504 includes a surface 504c parallel to the axial direction and an inclined surface 504b inclined with respect to the axial direction.

The surface 503g of the intermediate wheel body 503 and the surface 504c of the driven wheel body 504 are in contact with each other, and the inclined surface 503h of the intermediate wheel body 503 and the inclined surface 504b of the driven wheel body 504 are in contact with each other. The claw portion 503f of the intermediate wheel body 503 and the claw portion 504a of the driven wheel body 504 mesh with each other.

<Motion direction conversion mechanism between the drive wheel body 502 and the intermediate wheel body 503>
The intermediate wheel body 503 has a first position in which the claw portion 503f is separated from the claw portion 504a of the driven wheel body 504 and does not transmit the driving force of the drive wheel body 502 to the driven wheel body 504, and the axial direction. A second position in which the claw portion 503f meshes with the claw portion 504a of the driven wheel body 504 and transmits the driving force of the driving wheel body 502 to the driven wheel body 504 is provided so as to be slidable in the axial direction. ..

The first position is a position where the drive wheel body 502 and the intermediate wheel body 503 are in close contact with each other, and the convex portion 502a of the drive wheel body 502 and the bottom surface 503c of the concave portion 503a of the intermediate wheel body 503 are in contact with each other. At the second position, the convex portion 502a of the drive wheel body 502 and the transmission surface 503e of the concave portion 503a of the intermediate wheel body 503 are in contact with each other, and the claw portion 503f of the intermediate wheel body 503 and the claw portion 504a of the driven wheel body 504 are brought into contact with each other. It is the position to mesh.

The clutch unit 505 has a motion direction changing function that converts the driving force of the driving wheel body 502 into an axial force.

FIG. 6 is a schematic diagram illustrating a motion direction conversion function that converts a driving force of the driving wheel body 502 into an axial force. FIG. 6A is a schematic view showing a state in which the intermediate wheel body 503 is in the first position in the clutch portion 505. FIG. 6B is a schematic view showing a state in which the intermediate wheel body 503 is sliding from the first position to the second position in the clutch portion 505. FIG. 6C is a schematic view showing a state in which the intermediate wheel body 503 exists in the second position in the clutch portion 505.

As shown in FIG. 6A, in the initial state, the intermediate wheel body 503 is in the first position and is in close contact with the drive wheel body 502. When the drive wheel body 502 starts rotating in the forward direction (counterclockwise when viewed from right to left in the figure), as shown in FIG. 6 (b), the convex portion 502a of the drive wheel body 502 moves in the B direction in the figure. It rotates and moves, and the convex portion 502a of the drive wheel body 502 and the inclined surface 503d of the concave portion 503a of the intermediate wheel body 503 come into contact with each other. When the drive wheel 502 further rotates in the forward direction while the convex portion 502a of the drive wheel 502 and the inclined surface 503d of the concave portion 503a of the intermediate wheel 503 are in contact with each other, the inclined surface 503d of the driving force of the drive wheel 502 Due to the component force according to the inclination of, the force in the C direction in the figure acts on the intermediate wheel body 503, and the intermediate wheel body 503 slides in the C direction in the figure. In the motion direction changing mechanism that converts the driving force of the driving wheel 502 into a force in the C direction, the rotation of the driving wheel 502 exceeds a certain angle, and as shown in FIG. 6C, the convex of the driving wheel 502. When the portion 502a and the transmission surface 503e of the recess 503a of the intermediate wheel body 503 come into contact with each other, the conversion function is stopped. When the rotation of the drive wheel body 502 exceeds a certain angle, the intermediate wheel body 503 slides to the second position as shown in FIG. 6 (c), and the convex portion 502a of the drive wheel body 502 and the concave portion of the intermediate wheel body 503. The transmission surface 503e of the 503a comes into contact with the surface 503g of the claw portion 503f of the intermediate wheel body 503, and the surface 504c of the claw portion 504a of the driven wheel body 504 comes into contact with each other. When the drive wheel body 502 further rotates in the forward direction in this state, the rotation of the drive wheel body 502 is intermediate due to the contact between the convex portion 502a of the drive wheel body 502 and the transmission surface 503e of the concave portion 503a of the intermediate wheel body 503. It is transmitted to the wheel body 503, and the intermediate wheel body 503 rotates in the forward direction. Then, the rotation of the intermediate wheel body 503 is transmitted to the driven wheel body 504 by the contact between the surface 503 g of the claw portion 503f of the intermediate wheel body 503 and the surface 504c of the claw portion 504a of the driven wheel body 504, and the driven wheel body 504 is driven. The wheel rotates in the forward direction. In the present specification, the rotation of the drive wheel body 502 is transmitted to the intermediate wheel body 503 by the contact between the convex portion 502a of the drive wheel body 502 and the transmission surface 503e of the concave portion 503a of the intermediate wheel body 503. This is expressed as the drive wheel body 502 and the intermediate wheel body 503 being connected.

<Movement direction changing mechanism between the intermediate wheel body 503 and the driven wheel body 504>
Further, as described above, when the paper S is conveyed by the conveying force of the conveying roller 34, the paper feeding roller 331 stops rotating due to the driving force of the driving source, and is driven to rotate along with the conveying of the paper S. At this time, the clutch portion 505 converts the force of the driven rotation of the paper feed roller 331 into an axial force via the driven wheel body 504, and slides the intermediate wheel body 503 from the second position to the first position. , The clutch is disengaged.

FIG. 7 is a schematic diagram illustrating a motion direction changing mechanism between the intermediate wheel body 503 and the driven wheel body 504. FIG. 7A is a schematic view showing a state in which the intermediate wheel body 503 exists in the second position in the clutch portion 505. FIG. 7B is a schematic view showing a state in which the intermediate wheel body 503 is sliding from the second position to the first position in the clutch portion 505. FIG. 7C is a schematic view showing a state in which the intermediate wheel body 503 exists in the first position in the clutch portion 505.

As shown in FIG. 7A, when the driven wheel body 504 rotates in the forward direction (clockwise when viewed from the left to the right in the figure) with the intermediate wheel body 503 in the second position in the clutch portion 505. , As shown in FIG. 7B, the claw portion 504a of the driven wheel body 504 rotates and moves in the D direction in the figure. At this time, the inclined surface 504b of the claw portion 504a of the driven wheel body 504 and the inclined surface 503h of the claw portion 503f of the intermediate wheel body 503 are in contact with each other. The claw portion 504a of the driven wheel body 504 rotates in the D direction in the figure in a state where the inclined surface 504b of the claw portion 504a of the driven wheel body 504 and the inclined surface 503h of the claw portion 503f of the intermediate wheel body 503 are in contact with each other. When it moves, the force in the E direction in the figure acts on the intermediate wheel body 503 due to the component force corresponding to the inclination of the inclined surface 504b and the inclined surface 503h of the rotational force of the driven wheel body 504, and the intermediate wheel body 503 is shown in the figure. Slide in the E direction of. At this time, the inclined surface 503d of the concave portion 503a of the intermediate wheel body 503 and the convex portion 502a of the drive wheel body 502 are in contact with each other. Since the rotational drive by the drive source with respect to the rotary shaft 501 is stopped, the force in the F direction in the figure acts on the drive wheel 502 by the component force corresponding to the tilt of the tilt surface 503d of the slide force of the intermediate wheel 503. Then, the drive wheel body 502 rotates and moves in the F direction in the figure. Finally, as shown in FIG. 7C, the intermediate wheel body 503 slides to the first position, and the driven wheel body 504 is separated from the intermediate wheel body 503 and the drive wheel body 502.

In this way, the clutch portion 505 transmits the rotation of the driving wheel body to the driven wheel body when the driving wheel body 504 rotates forward by the drive source, and when the driven wheel body 504 is driven to rotate, that is, relative to each other. When the drive wheel body 502 rotates in the reverse direction, the drive wheel body 502 and the driven wheel body 504 are separated from each other, and the rotation is not transmitted. That is, the clutch portion 505 functions as a one-way clutch that transmits rotation in the forward direction and does not transmit rotation in the reverse direction.

<Constituent material of restraining member 507>
As shown in FIG. 3, in order to give rotational resistance to the intermediate wheel body 503 and suppress the intermediate wheel body 503 from rotating with the rotation of the drive wheel body 502 in the state where the intermediate wheel body 503 is in the first position, the intermediate wheel body 503 is intermediate. A restraining member 507 that comes into contact with the wheel body 503 is provided. In order to give rotational resistance to the intermediate wheel body 503, it is desirable that the restraining member 507 is formed by using a polymer elastic material (polymer material such as rubber).

Further, the restraining member 507 suppresses the rotation of the intermediate wheel body 503 when it is in the first position, and rotates in conjunction with the drive wheel body 502 when it is in the second position. When the intermediate wheel body 503 is in the second position and rotates in conjunction with the drive wheel body 502, static electricity is generated in the suppressing member 507 and the intermediate wheel body 503 due to friction between the intermediate wheel body 503 and the suppressing member 507. there is a possibility. In order to prevent the adverse effect of static electricity, it is desirable that the suppressing member 507 is formed by using a conductive material (a conductive material such as carbon black or metal powder), and further grounded as shown in FIG. Therefore, it is desirable that the restraining member 507 is formed of a composition made of a conductive material, a polymer elastic material, or the like.
(Supplement)
Although the present invention has been described above based on the embodiments, it goes without saying that the present invention is not limited to the above-described embodiments, and the following modifications are included in the technical scope of the present invention. ..

(1) When the restraining member 507 is formed as shown in FIG. 3, the restraining member 507 comes into contact with the driven wheel body 504 in the same manner as the intermediate wheel body 503. Therefore, the friction between the restraining member 507 and the driven wheel body 504 may generate static electricity in the driven wheel body 504. In order to prevent the adverse effect of static electricity, the driven wheel body 504 may be formed by using a conductive material. The driven wheel body 504 may be further grounded as shown in FIG.

(2) In the embodiment, it is desirable that the restraining member 507 is an elastic body made of a polymer elastic material, but it does not have to be an elastic body as long as it gives rotational resistance to the intermediate ring body 503. ..

(3) In the above-described embodiment, the clutch (drive transmission device) for transmitting the driving force of the drive source to the paper feed roller 331 of the paper feed unit 3 has been described, but a clutch having the same configuration as this is used as the image reading device 1. It may be used as a clutch for transmitting the driving force of the driving source to the paper feeding roller 421 of the automatic document transporting unit 40. Further, if the torque to be transmitted is relatively small, such as a clutch that transmits the driving force of the drive source to the roller that conveys the paper, it can be adopted as a general one-way clutch.

The present invention is useful as a clutch that transmits a relatively small torque, particularly a clutch that transmits the driving force of a drive source to a roller that conveys paper.

1 Image reader 2 Image forming unit 3 Paper feeding unit 5 Control unit 10 Image reading unit 32 Feeding roller 33 Separation roller vs. 34 Conveying roller 331 Paper feeding roller 501 Rotating shaft 502 Driving wheel 503 Intermediate wheel 504 Driven wheel 505 Clutch part 506 Frame 507 Suppressing member 511 Rotating shaft 512 Driving wheel body 513 Intermediate wheel body 514 Driven wheel body 515 Clutch part

Claims (4)

Between the drive wheel body connected to the drive source, the driven wheel body coaxially connected to the seat transport roller on the same axis as the drive wheel body, and between the drive wheel body and the driven wheel body. A drive coupling device including an intermediate wheel body slidably provided in the axial direction between the two wheel bodies.
The drive wheel body and the intermediate wheel body are in close contact with each other at the initial stage of rotation, and the intermediate wheel body is rotatable with respect to the drive wheel body until the drive wheel body rotates by a certain angle. The motion direction conversion mechanism provided between the intermediate wheel body and the drive wheel body pushes the intermediate wheel body in the axial direction to approach the driven wheel body, and when the angle exceeds a certain angle, the motion direction conversion mechanism is activated. The conversion function is stopped, the drive wheel body and the intermediate wheel body are connected, and the rotational force of the drive wheel body is transmitted to the intermediate wheel body.
A unidirectional clutch mechanism is provided between the intermediate wheel body and the drive wheel body so that the intermediate wheel body functions in close contact with the driven wheel body.
Further, a restraining member for suppressing the intermediate wheel body from being rotated by the drive wheel body before the intermediate wheel body comes into close contact with the driven wheel body is provided in a state of being in contact with the intermediate wheel body. Drive coupling device characterized by being The motion direction changing mechanism is
A convex portion provided on a surface of the drive wheel body facing the intermediate wheel body, and
It is provided on the surface of the intermediate wheel body facing the drive wheel body, and is composed of a concave portion that receives the convex portion.
A part of the bottom surface of the concave portion is inclined in the direction of the intermediate wheel body, and the driving wheel body is rotated in a state of being in contact with the convex portion, so that the driving force of the driving wheel body according to the inclination can be obtained. The drive coupling device according to claim 1, wherein the intermediate wheel body has an inclined surface that slides in the direction of the driven wheel body by a component force. The drive coupling device according to claim 1, wherein the restraining member is made of a conductive material. The drive coupling device according to claim 3, wherein the restraining member is grounded.

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