JPH07257776A - Drive transmission device and image forming apparatus - Google Patents

Abstract

(57) [Summary] [Purpose] The purpose is to facilitate the engagement of the driven gear and the driven gear that come in and out of contact with each other. [Structure] The input gear 9 and the drum gear 10 are brought into contact with and separated from each other. An intermediate gear 8 and an input gear 9 are rotatably provided on a fixed gear shaft 13, and are connected by a torsion coil spring 12 so that play is provided on both sides in the rotational direction by clutch pawls 8a and 9a. Drive-side gear train or drum gear 10 via the drive-side intermediate gear 8
The spring force for rotating the torsion coil spring 12 by the play L1 or L2 between the clutch pawls is made smaller than the rotation resistance for rotating the load side via. Input gear 9 and drum gear 10
When engaged with each other, the input gear 9 rotates lightly against the spring force of the torsion coil spring 12 within the play L1> L2. Power transmission is by contact of the clutch pawls 8a and 9a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drive transmission device and an image forming apparatus for transmitting a driving force from an apparatus body to a unit detachable from the apparatus body.

[0002]

2. Description of the Related Art Conventionally, an image forming apparatus has been proposed which is equipped with a device main body having a drive source and a unit on the driven side detachable from the device main body, for example, a means for forming an image by connecting a process cartridge. .

The above-mentioned process cartridge is
The charging means, the developing means or the cleaning means and the electrophotographic photosensitive member are integrally formed into a cartridge, and the cartridge can be attached to and detached from the main body of the image forming apparatus (for example, copying machine, LBP, etc.). Also, at least one of the charging means, the developing means, and the cleaning means and the electrophotographic photosensitive member are integrally made into a cartridge so as to be attachable to and detachable from the main body of the image forming apparatus (for example, copying machine, LBP, etc.). Further, it means that at least the developing means and the electrophotographic photosensitive member are integrally made into a cartridge so as to be attachable to and detachable from the main body of the apparatus (for example, a copying machine, LBP, etc.).

In the above description, the driven process cartridge is mounted on the main body of the apparatus by the hand of a user or the like. When the process cartridge on the driven side is mounted on the apparatus body, the rotation of the apparatus body and the process cartridge on the driven side is transmitted to the drive side gear to which the rotation is transmitted from the drive source provided in the apparatus body and the gear on the driven side. This is achieved by engaging the driven-side gear of the process cartridge on the driving side.

Conventionally, the engagement between the driving side gear and the driven side gear has been achieved by using an additional mechanism of a swing gear in which a gear is attached to the tip end of the swing arm at the meshing portion of the gear. Alternatively, the drive side or driven side gear is temporarily avoided in the thrust direction and a drive force is applied to the gears to engage with each other.

Further, it has been achieved by simply pushing in with a hand by a user and engaging them by engaging them against a resistance or a load on a driving side.

[0007]

However, in the above-mentioned conventional example, 1. Is the rocking gear locked at the gear mesh position?
It is necessary to take measures to prevent the tooth from escaping under load, which is costly and space-consuming due to the complexity of the device. Further, in the case of a helical gear, it is difficult to achieve alignment, so that the purpose of increasing the number of simultaneous meshing teeth and improving transmission accuracy by utilizing the helical gear cannot be sufficiently achieved. 2. When the additional mechanism of the swing gear device is not used, the user is burdened with an extra operation force (in many cases, a force for slightly rotating against the load on the drive side or the process cartridge side). I don't like the feeling of operation.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a drive transmission device which solves the above-mentioned drawbacks of the prior art and is user-friendly, has a small space, and is inexpensive.

[0009]

According to a first aspect of the present invention, there is provided an apparatus for driving a drive-side gear, the rotation of which is transmitted from a drive source, and a driven-side gear connected to a load member, in such a manner that they can come into contact with and separate from each other. At least one of the side gear and the driven side gear is connected to the drive source or the load member with play in the rotation direction, and when the drive side gear and the driven side gear are separated, the play is always in both rotation directions. The drive transmission device is characterized in that

According to a second aspect of the present invention, in a device in which a drive-side gear to which rotation is transmitted from a drive source and a driven-side gear connected to a load are engaged and disengageable, the gear from the drive source is engaged. The intermediate gear and the driven gear that mesh with the driven gear.The intermediate gear and the driving gear are connected by a coaxial clutch so as to have a play in the rotational direction, and the driven gear and the driven gear. The drive transmission device is characterized in that the play is always in both rotational directions when the side gear is separated.

A third aspect of the present invention is the drive transmission device according to the second aspect, wherein the play is caused by a spring member interposed between the driving side and the driven side of the clutch. is there.

A fourth aspect of the present invention has a process cartridge which can be attached to and detached from the apparatus main body, and a drive gear provided on the apparatus main body side when the process cartridge is attached to and detached from the apparatus main body, and a driven gear provided on the process cartridge. In the image forming apparatus in which the
An image forming apparatus comprising the drive transmission device according to any one of the inventions.

[0013]

Embodiments of the present invention will be described below with reference to the drawings.

[First Embodiment] An image forming apparatus to which the present invention is applied is shown in FIGS. In FIG. 12, a document 21 is placed on a document table glass 22, and reflected light from the document 21 on the document table glass 22 illuminated by a moving light source 23 is reflected by a mirror group 24 having a fixed mirror and a moving mirror, and a mirror. The original image is placed in the group 24 and is imaged on the photosensitive drum 11 having a drum shape through the lens 25 for enlarging and reducing the original image at a set magnification.

The photosensitive drum 11 is rotating in the direction of the arrow in the figure, and is uniformly charged by the primary charging device 43 to form a latent image on the original image, and the developing device 27 applies toner to the latent image. Form a toner image, and reach the transfer position. The residual toner on the photosensitive drum 11 after the transfer is cleaned by the cleaning device 28.
Will be removed. Each member and lens 25 described above,
A moving mirror in the mirror group 24, a motor as a drive source for driving the light source 23, and a power transmission member are attached to the upper body 2.

In accordance with the formation of the toner image on the photosensitive drum 11, the transfer paper in the paper feeding cassette 30 is fed to one by one by a feeding roller (not shown), and is transferred by the registration roller 31 to the photosensitive drum 1.
1 and the toner image on the photosensitive drum 1
1 and the transfer charger 32, and the toner image on the photosensitive drum 11 is transferred onto the transfer paper. After the transfer, the transfer sheet supporting the toner image is guided by the guide member 33 to reach the fixing device 34, and the toner image is permanently fixed to the transfer sheet and discharged to the outside of the apparatus. The above members are attached to the lower body 3.
A drive transmission member between the photosensitive drum 11, the developing device 27, and a main motor (not shown) that drives these and a main motor are attached to the upper main body 2 side.

The apparatus main body 4 is divided into a lower main body 3 and an upper main body 2, and a lower frame and an upper frame of each of these are connected by a rotary support shaft 36. The rotary support shaft 36 connects a support shaft support portion 37 formed integrally with the lower frame and a single support shaft bearing 42 fixed to the upper frame. It should be noted that the bearing 22 is supported against the weight of the upper body 2.
A compression coil spring 38 is compressed between the lower body 3 and the lower body 3.

In the above, the photosensitive drum 11, the primary charging device 43, the developing device 27, and the cleaning device 28 are case 29.
The process cartridge 1 is housed inside to form an integrated unit, and can be attached to and detached from the upper main body 2 from the direction perpendicular to the transfer paper feeding direction or from the direction following the transfer paper feeding direction. Has become.

As shown in FIGS. 4 and 5, a spiral drum gear 10 as a driven gear is fixed to the end of the photosensitive drum 11, and the photosensitive drum 11 is fixed to the case 29 of the process cartridge 1. Both ends in the axial direction are rotatably supported by a book fixed shaft 35.

FIG. 1 shows the drive transmission device in a state where the process cartridge 1 is mounted on the upper main body 2. An input gear 9 provided as a drive side gear of the drive side gear train provided on the upper main body 2 meshes with the drum gear 10. The motor gear 7 fixed to the motor shaft 6a of the motor 6 provided in the upper main body 2 meshes with the intermediate gear 8, and the intermediate gear 8 and the input gear 9 are respectively mounted on the gear shaft 13 of the fixed shaft fixed to the upper main body 2. It is rotatably supported, and the clutch pawl 8a provided on the boss portion of the intermediate gear 8 and the clutch pawl 9a provided on the boss portion of the input gear 9 engage with each other with play in both rotational directions. That is, as shown in FIG. 2, this example is provided with two-tooth clutch pawls 8a and 9a.
The circumferential width L1 of the valley of a is larger than the circumferential width L2 of the claw of the clutch claw 9a, and the crest of the clutch claw 9a engages with the valley of the clutch 8a, as shown in FIG. Have play S.

The inner diameters d2 of the clutch pawls 8a and 9a and the diameter d1 of the gear shaft 13 are d1 <d2, and a torsion coil spring 12 is inserted in the gap between the inner periphery of the clutch pawls 8a and 9a and the gear shaft 13. Both ends of the wire of the torsion coil spring 12 are inserted into slits 8b and 9b provided axially and radially from the roots of the clutch pawls 8a and 9a, respectively, so that the torsion coil spring 12 is not twisted. Then, as shown in FIGS. 1 and 6, the clutch pawls 8a, 9a
There is a play S in any rotation direction between the contact surfaces that are pressed against each other when the rotational force is applied. However, in the above-described image forming apparatus, the rotation direction when the driving force is applied is one direction as described with reference to FIG.

When the process cartridge 1 is removed from the upper main body 2 (FIG. 6), the input gear 9 is moved to the gear shaft 13
Since there is no load above, there is play (L1−L2) / 2 = S on both sides in the rotational direction between the contact surfaces of the clutch pawls 8a and 9a. In the above, the spring force of the torsion coil spring 12 is the rotational resistance of the torsion coil spring 12 for eliminating the play on one side between the clutch pawls 8a and 9a, and the rotational resistance for rotating the gear train on the drive side via the intermediate gear 8, Or drum gear 1
It is smaller than the rotation resistance on the load side that rotates 0.

The operation of the above configuration will be described.

In FIG. 3, when the process cartridge 1 is inserted in the direction of arrow D and pushed in, the drum gear 10 moves in the tooth trace direction and engages with the input gear 9. At that time, when not in the meshing position, the input gear 9 and the drum key 10 act on their respective chamfers and try to rotate each other. At this time, since load torque (bearing frictional resistance in the process cartridge 1, gear frictional resistance between the gear coaxial with the developing roller (not shown) and the drum gear 10, etc.) is applied to the drum gear 10 side, it does not rotate easily, but the input gear does not rotate. 9 rotates on the gear shaft 13 against the spring force of the torsion coil spring 12, and the drum gear 10 moves in the tooth trace direction to move the input gear 9
Mesh with.

Here, when the motor 6 is energized in accordance with the image forming operation, the rotation is transmitted to the motor shaft 6a, the motor gear 7, and the intermediate gear 8, and the input gear 9 has a rotational resistance on the load side. The clutch pawl 8a is a torsion coil spring 12
The clutch claws 8a, 9a rotate against the play S on one side.
And the input gear 9 is pressed in the circumferential direction at each contact surface.
The input gear 9 rotates the drum gear 10.

In the present invention, since the play S is provided on both sides of the clutch pawls 8a, 9a in the rotational direction, the input gear 9,
This is especially effective when the ten pairs of drum gears are helical gears. It is desirable that the play in the rotational direction between the clutch pawls 8a and 9a be provided on one side and be equal to one tooth of the input gear 9.

In the present embodiment, a claw clutch joint is provided between the input gear 9 and the intermediate gear 8 that mesh with the drum gear 10 of the process cartridge 1 so that the play is increased and the torsion coil spring takes an intermediate position. If there are more gears that are in mesh with each other in a row, they may be provided in any range as long as they can be rotated between the motor 6 and the input gear 9 with a light force from the input gear 9, and can be freely rotated on the rotary shaft that receives the driving force. It is also possible to support the gear, have a play in the rotation direction between the rotation shaft and the gear, and have play under no load on both sides in the rotation direction.

[Second Embodiment] FIG. 7 is an exploded perspective view of the second embodiment. Although the illustration of the gear train is omitted, it is the same as that shown in FIG. 1. The intermediate gear 8 in FIG. 1 is the intermediate gear 15 in the second embodiment, and the input gear 9 in FIG. 1 is the input gear 9 in the second embodiment. It is the input gear 14. The intermediate gear 15 and the input gear 14 which are rotatable on the gear shaft 13 are respectively clutch pawls 14a and 15
The clutch claws 14a and 15a are engaged with play on both sides in the rotational direction. As shown in FIG. 8A, an axial and radial slit 15b is provided in the middle of the peak of the clutch pawl 15a of the intermediate gear 15, and the clutch pawl 14a has a diameter larger than that of the clutch pawl 14a at the center thereof. Is small, and the spring clearance 1 is provided between the clutch claw 15a and
A reduced diameter boss 14b is provided so as to produce 6a. The boss 14b has an axial and radial slit 14c.
Is provided. Slit 1 provided on each clutch claw
Both ends of the leaf spring 16 are press-fitted into 5b and 14c, respectively. As shown in FIG. 8A, the leaf spring 16 is activated when the rotational force is not applied between the intermediate gear 15 and the input gear 14.
Has a flat plate-shaped original shape, and the valleys of the clutch pawls 15a and the peaks of the clutch pawls 14a play in both directions with respect to rotation S, S.
Are installed evenly and meshed. In the above, the leaf spring 1
The spring force of 6 is the rotational resistance of the leaf spring 16 for eliminating the play on one side between the clutch pawls 14a and 15b, the rotational resistance for rotating the intermediate gear 15 against the drive side gear train, or the drum gear 10. It is smaller than the rotation resistance on the load side to rotate.

When the process cartridge 1 is mounted on the upper main body 2 in the state of FIG. 8A where the process cartridge 1 is not mounted on the upper main body 2 of the apparatus main body 4, the drum gear 10 tries to engage with the input gear 14. . At this time, when the drum gear 10 and the input gear 14 are not in the meshing position, the tooth chamfering of the gears 10 and 14 causes the input gear 14 to move to the maximum in the direction of arrow E shown in FIG. As described above, since the clutch pawls 14a and 15a can be rotated to the positions where the clutch surfaces 14d and 15d come into contact with each other, the input gear 14 and the drum gear 10 are engaged by that time.

In the state of (a) of FIG. 8, when the motor 6 rotates, the intermediate gear 15 rotates in the direction opposite to the arrow E shown in (a) of FIG.
Reference numeral 4 drives the drum gear 10. Of course, when the process cartridge 1 is attached to the upper main body 2 of the apparatus main body 4, the input gear 14 may be rotated in the direction opposite to the arrow E shown in FIG. Also in that case, the intermediate gear 15 is driven by driving the motor 6.
Rotates in the direction opposite to the arrow E, and enters the state of FIG. 8A, and the rotation of the intermediate gear 15 is transmitted to the input gear 14.
When the intermediate gear 15 is stopped by stopping the motor 6, the rotational force of the leaf spring 16 is smaller than the drive-side rotation resistance or the load-side rotation resistance, so that the state of (a) in FIG. 8 is maintained.
When the process cartridge 1 is removed and the input gear 14 and the drum gear 10 are disengaged from each other, the input gear 14 is rotated by the leaf spring 16 in the direction of the arrow shown in (c) of FIG. Plays S and S occur on both sides in the rotation direction (Fig. 8 (c)).

According to the second embodiment, it is clear that the leaf spring 16 can be made of plastic or the like. However, in addition to this, in the case of this construction, the leaf spring 16 is connected to the input gear 1.
It is also possible to integrally mold the same material as No. 4 so as to have elasticity, which leads to cost reduction.

[Third Embodiment] Next, a third embodiment will be described.

FIG. 9 is an exploded perspective view showing the third embodiment. The difference from the first and second embodiments is that a play in the rotational direction is provided in the driven process cartridge 1.

As shown in FIG. 9, the photosensitive drum 11 and the drum gear 19 are respectively provided with clutch pawls 11a and 19a at their end portions and are engaged with each other via a torsion coil spring 17, so that the clutch pawl 1
1a and 19a are engaged so as to have a play in both rotation directions.

It should be noted that instead of the torsion coil spring, both clutches may be connected by a leaf spring as in the second embodiment.

According to the third embodiment, since play is provided on both sides of the load on the load side, even if the drive input gear 20 on the apparatus body side that meshes with the drum gear 19 meshes with the intermediate gear 21 instead of the step gear. There is no need to create a space forcibly, and the size can be reduced.

[Embodiment 4] Next, another embodiment 4 will be described.

10 and 11 are views showing this embodiment. In the first to third embodiments described above, the detachable process cartridge is mainly attached to the input gear in a direction substantially equal to the thrust direction.

In this embodiment, the process cartridge 1 is detachable from the apparatus upper frame 2 in the direction of the sheet feeding direction as shown by arrow E in FIG. A configuration is shown in which the drum gear 10 is engaged with the input gear 9 in the radial direction (vertical or horizontal direction) as indicated by the arrow mark in FIG.

When the drum gear 10 is engaged with the input gear 9 from the direction of the arrow C as shown in FIG. 11, for example, the input gear 9 rotates in the direction of the arrow C and biases the play between the clutch pawls. Input gear 9 and drum gear 10
Teeth mesh with each other.

Even in this case, if any one of the embodiments of the present invention described above is used with a clutch provided with play on both sides in the no-load rotation direction, it can be used not only for the helical gear but also for the spur gear pair. Even if the drive transmission device is capable of driving a particularly heavy load, it causes a light load at the time of engagement and the teeth escape, so that the contact at the tip of the tooth is alleviated.

As shown in FIG. 11, if the input gear 9 and the drum gear 10 are respectively + shifted, the tooth tips become smaller, and the engagement of the process cartridge 1 at the time of mounting can be facilitated.

In the embodiment, since play is provided on both sides of the claws and valleys of the clutch pawls that mesh with each other, both ends of the spring member are locked between the clutch pawl constituent base materials on the driving side and the driven side. Can also be obtained by attaching magnets of the same polarity so as to face the contact surfaces of the clutch pawls that mesh with each other. or,
As shown in FIG. 13, the clutch claw 38 is provided with a cylinder 41 capable of sealingly entering and exiting the piston 39 projecting opposite the valley of the clutch claw 38 on either the driving side or the driven side. The compressed gas may be enclosed and the piston 39 may clamp the other clutch pawl 44. As described above, any means may be used to provide the play on both sides in the rotation direction under no load.

[0044]

According to a first aspect of the present invention, in a device in which a driving gear to which rotation is transmitted from a driving source and a driven gear connected to a load member are engaged with each other in a contactable / separable manner, At least one of the drive side gears is connected to the drive source or the load member with play in the rotation direction, and when the drive side gear and the driven side gear are separated, the play is always in both rotation directions. Therefore, the driven side gear and the driving side gear can be meshed with each other without difficulty, and since the rocking gear device and the like are not required, the cost can be reduced and the space can be reduced.

In a second aspect of the present invention, in a device in which a drive-side gear whose rotation is transmitted from a drive source and a driven-side gear connected to a load are engaged and disengageable with each other, the gear from the drive source is engaged. The intermediate gear and the driven gear are engaged with the driven gear, and the intermediate gear and the driving gear are connected by a coaxial clutch so as to have a play in the rotational direction, and the intermediate gear and the driven gear are connected to each other. When the driven gear is separated,
Since the play is always in both rotation directions, it is sufficient to provide the play between the clutch pawls, so that no particular space is required on either the drive side or the load side to which the rotational force is transmitted. Also, due to the play between the clutches, the driven side gear and the driving side gear can be easily engaged with each other.
Moreover, since no swing gear device or the like is required, cost reduction,
This has the effect of enabling a small space.

In the third invention of the present invention, in the second invention, since the spring member is used to maintain the play, the construction is simple and the operation is reliable.

A fourth aspect of the present invention has a process cartridge which is attachable to and detachable from the apparatus main body, and a drive gear provided on the apparatus main body side when the process cartridge is attached to and detached from the apparatus main body and a driven gear provided on the process cartridge. Since the invention of any one of the first to third aspects is applied to the image forming apparatus in which the process cartridge is engaged, the drive gear of the apparatus main body and the driven gear of the process cartridge are easily engaged when the process cartridge is attached to or detached from the apparatus main body. The effect is that they can be combined.

[Brief description of drawings]

FIG. 1 is a perspective view of a drive transmission device according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view of FIG.

FIG. 3 is a perspective view of an image forming apparatus to which the present invention is applied.

FIG. 4 is a perspective view of a process cartridge.

FIG. 5 is a perspective view showing a driven gear portion of the process cartridge.

FIG. 6 is a perspective view showing the operation of the first embodiment of the present invention.

FIG. 7 is an exploded perspective view of a second embodiment of the present invention.

8A, 8B and 8C are front views showing the operation of the second embodiment.

FIG. 9 is an exploded perspective view of a third embodiment of the present invention.

FIG. 10 is a perspective view of a fourth embodiment of the present invention.

11 is a front view showing the operation of FIG.

FIG. 12 is a vertical sectional view of an image forming apparatus to which the present invention is applied.

FIG. 13 is a front sectional view of a clutch showing a modified example for providing play.

[Explanation of symbols]

 1 Process Cartridge 2 Upper Body 3 Lower Body 4 Device Body 6 Motor 8 Intermediate Gear 8a, 9a Clutch Claw 8b, 9b Slit 9 Input Gear 10 Drum Gear 11 Photosensitive Drum 11a Clutch Claw 12 Torsion Coil Spring 13 Gear Axis 14 Input Gear 14a Clutch Claw 15 Intermediate Gear 15a Clutch Claw 16 Leaf Spring 17 Torsion Coil Spring 19 Drum Gear 19a Clutch Claw 20 Drive Input Gear

Claims (4)

[Claims] 1. A device in which a drive-side gear to which rotation is transmitted from a drive source and a driven-side gear connected to a load member engage with each other in a contactable / separable manner, at least one of a drive-side gear and a driven-side gear The drive transmission device is characterized in that the drive source or the load member is connected with play in the rotation direction, and the play is always in both rotation directions when the drive side gear and the driven side gear are separated. 2. A device in which a drive-side gear, to which rotation is transmitted from a drive source, and a driven-side gear, which is connected to a load, engage with each other in a contactable / separable manner, and an intermediate gear and a driven gear that mesh with the gear from the drive source. Has a drive-side gear that meshes with the gear on the side, and the intermediate gear and the drive-side gear are connected by a coaxial clutch so that there is play in the rotational direction, and when the drive-side gear and the driven-side gear are separated. Is a drive transmission device characterized in that the play is always in both rotation directions. 3. The drive transmission device according to claim 2, wherein the play is caused by a spring member interposed between a driving side and a driven side of the clutch. 4. A process cartridge detachably mountable to the apparatus main body, wherein a driven gear provided to the process cartridge is engaged with a drive gear provided to the apparatus main body side when the process cartridge is attached to and detached from the apparatus main body. An image forming apparatus comprising the drive transmission device according to any one of claims 1 to 3.