JP3512862B2 - Gearing - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transmission having a driving side rotating member and a driven side rotating member.

[0002]

2. Description of the Related Art Various mechanical devices are equipped with various rotary members. For example, in an image forming apparatus such as a copying machine, a printer or a facsimile, various image forming process units necessary for image formation are arranged around a photoconductor, and for example, one developing unit includes a developing roller or a developing roller. A rotating member such as a developer stirring member is provided.

Such a developing unit is provided with a drive side rotating member including a gear which receives a drive from the image forming apparatus main body side, and the driven side rotating member including, for example, a rotating shaft is rotationally driven by the gear. The transmission device having the driving-side rotating member and the driven-side rotating member is configured to rotationally drive the rotating member in the developing unit. At that time, if foreign matter or the like is mixed in the developing unit or if the developer is excessively blocked, the load torque of the rotating member is increased at once, causing various problems. For example, in a configuration in which a gear on the developing unit side is meshed with an idle gear on the image forming apparatus main body, a stud shaft or the like that rotatably supports the idle gear is deformed.

Such an idle gear merely serves to change the direction of rotation, and is not so rigid as a stud shaft. Therefore, the load torque on the driven side increases due to such a weak member. Is affected. In some cases, if the developing unit is locked due to foreign matter being caught, the stud shaft may be damaged, the rotating member may not be driven, and the repair may not be easily performed.

Therefore, it is possible to provide a motor for directly driving each image forming process unit and stop the motor when an excessive load torque is detected by some torque detecting means. With such a configuration, it is necessary to provide a motor, torque detecting means, etc. for each unit. If such a configuration is provided, the device configuration becomes large and the device cost rises.
In addition, an electromagnetic clutch and a torque limiter are also known, and a transmission device configured to prevent the rotation from being transmitted to the rotating member when the load torque of the rotating member becomes excessive due to the electromagnetic clutch and the torque limiter is also known. Is expensive, so it suffers from the drawback of increasing the cost of the transmission.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to, when the load torque of a driven side rotating member becomes excessive, rotate the driven side rotating member by itself without using torque detecting means or the like. The purpose of the present invention is to provide a transmission device capable of stopping.

[0007]

In order to achieve the above object, the present invention has a driving side rotating member and a driven side rotating member, and the former driving side rotating member and the latter driven side rotating member. And a member for engaging with each other to transmit rotation from the former drive-side rotating member to the latter driven-side rotating member. At least one of the driven part and the engaged part is designed to prohibit the transmission of rotation from the driving side rotating member to the driven side rotating member when the load torque of the driven side rotating member becomes excessive. It is formed so as to be deformed or broken by itself by an external force applied from one side, one of the driving side rotating member and the driven side rotating member is a rotating body having a hole in its rotation center part, and the other is fitted in the hole. A rotating shaft having a combined shaft portion, wherein the rotating body is An engagement that engages with the tip end surface of the protrusion so as to enable rotation transmission between the rotating body and the rotation shaft on the shaft. A surface is formed, and one of the protrusion and the engaging surface constitutes the engaging portion, and the other constitutes the engaged portion. We propose a transmission characterized in that notches are formed on both sides of the tip surface.

[0008]

[0009]

Furthermore, it is particularly advantageous that the notch is formed even in a region outside the rotation locus of the outer peripheral portion of the maximum outer diameter of the shaft portion fitted in the hole.

In order to achieve the above object, the present invention provides
A driving side rotating member and a driven side rotating member, and the former driving side rotating member and the latter driven side rotating member are engaged with each other so that the former driving side rotating member and the latter side rotating member are engaged with each other. In the transmission device, each of which has an engaging portion and an engaged portion for transmitting rotation to the driving side rotating member, wherein at least one of the engaging portion and the engaged portion is a load of the driven side rotating member. When the torque becomes excessive, it is formed so as to be deformed or broken by itself by an external force applied from its counterpart in order to prohibit the transmission of rotation from the driving side rotating member to the driven side rotating member,
One of the driving-side rotating member and the driven-side rotating member is a rotating body having a hole in its rotation center portion, and the other is a rotating shaft having a shaft portion fitted in the hole, and the rotating body is
It has a protrusion protruding toward the center of the hole, and engages with the shaft portion at the tip end surface of the protrusion so as to enable rotation transmission between the rotating body and the rotation shaft. An engaging surface is formed, and one of the protruding portion and the engaging surface constitutes the engaging portion, and the other constitutes the engaged portion, and the protruding portion is driven to rotate. A transmission device characterized in that it has a minimum width portion that induces deformation or breakage of the protrusion when the load torque of the member becomes excessive.

Further, it is advantageous that the minimum width portion is formed on a protrusion portion outside the rotation locus of the outer peripheral portion of the maximum outer diameter of the shaft portion fitted in the hole.

In order to achieve the above object, the present invention provides
A driving side rotating member and a driven side rotating member, and the former driving side rotating member and the latter driven side rotating member are engaged with each other so that the former driving side rotating member and the latter side rotating member are engaged with each other. In the transmission device, each of which has an engaging portion and an engaged portion for transmitting rotation to the driving side rotating member, wherein at least one of the engaging portion and the engaged portion is a load of the driven side rotating member. When the torque becomes excessive, it is formed so as to be deformed or broken by itself by an external force applied from its counterpart in order to prohibit the transmission of rotation from the driving side rotating member to the driven side rotating member,
One of the driving-side rotating member and the driven-side rotating member is a rotating body having a hole in its rotation center, and the other is a rotating shaft having a shaft portion fitted in the hole, and the rotating body is
It has a protrusion protruding toward the center of the hole, and engages with the shaft portion at the tip end surface of the protrusion so as to enable rotation transmission between the rotating body and the rotation shaft. An engaging surface is formed, and one of the protruding portion and the engaging surface constitutes the engaging portion, and the other constitutes the engaged portion, and in the central axis direction of the rotating body. The thickness of the protrusion is
A transmission device characterized by being set thinner than the total thickness of the rotating body in the central axis direction is proposed.

[0014]

[0015]

[0016]

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings.

FIG. 1 is a partial sectional front view showing a transmission device according to an embodiment of the present invention, and FIG. 2 is a schematic configuration diagram of an image forming apparatus which is an example of a mechanical device using such a transmission device. is there.

In FIG. 2, reference numeral 1 denotes a drum-shaped photoconductor which is an example of a latent image carrier, and the photoconductor 1 is rotationally driven clockwise in the drawing. At the time of this rotation, the surface of the photoconductor 1 is uniformly charged by the charging roller 2 which rotates in pressure contact with the photoconductor 1. Then, the exposure unit (not shown) performs image exposure or optical writing on the photoconductor 1 in the exposure unit 3, whereby a predetermined electrostatic latent image is formed on the surface of the photoconductor 1.

A developing unit 4 arranged to face the photoconductor 1.
Is provided with rotating members such as a developing roller 6 and a developer stirring and supplying roller 7 in the unit casing 5, and these are rotationally driven in the directions of arrows in FIG. The developer (not shown) in the unit casing 5 is supplied to the developing roller 6 via the developer agitating and supplying roller 7, and the developer supplied to the developing roller 6 is carried and conveyed on the same roller. By the developer thus formed, the electrostatic latent image formed on the photoconductor 1 is visualized as a toner image.

This toner image passes through the facing portion of the pre-transfer lamp 8 and then contacts the transfer paper 11 sent by the registration roller pair 9 against the photoconductor 1 via the transfer paper 11. It is transferred by the action of the transfer device composed of 12. After this transfer, the transfer paper 11 is conveyed toward the fixing unit 15 by the conveyor belt 14 through the portion of the charge removing member 13 for improving the separability of the transfer paper and discharging the transfer paper. At
The transferred toner image transferred onto the transfer paper is fixed. On the other hand, the surface of the photoconductor 1 after the transfer of the toner image is cleaned by the cleaning device 16, and the surface thereof is destaticized by the destaticizing member 17 to prepare for the next image formation. In FIG. 2, hatching showing the cross section of each element is omitted.

The transmission shown in FIG. 1 has a gear 18 which is an example of a driving side rotating member, and a rotary shaft 30 which is an example of a driven side rotating member which is rotationally driven by the gear 18. A tooth portion 19 is formed on the entire outer peripheral surface of 18. In this example, the rotating shaft 30 is the roller shaft of the developing roller 6 shown in FIG. 2, and the rotating shaft 30 is rotated counterclockwise in FIGS. The developing roller 6 is rotationally driven counterclockwise in FIG. 2 to execute the above-described developing operation. The gear 18 and the rotary shaft 30 are made of an appropriate material such as metal or synthetic resin, and preferably made of synthetic resin.

As shown in FIG. 3, the gear 18 has a hole 21 at its center of rotation, and the shaft portion 30A on one end side of the rotary shaft 30 is fitted into the hole 21. As described above, the rotating shaft 30 that is an example of the driven-side rotating member fits into the hole 21 of the gear 18 that is an example of the driving-side rotating member.
It has A. Rotating shaft 30 and its shaft portion 30
The central axis X that is the rotation center of A and the central axis X that is the rotation center of the gear 18 coincide with each other as shown in FIG.

The gear 18 has a protrusion 20 having a width W (FIG. 3) that protrudes toward the center (center axis) of the hole 21.
On the other hand, the shaft portion 30A of the rotating shaft 30 is formed with an engagement surface 30B that engages with the tip end surface 20A of the protrusion 20. That is, as shown in FIG. 5, the rotary shaft 30 has a general cross-sectional shape that is circular, and the shaft portion 30A fitted into the hole 21 of the gear 18 has a substantially D-shaped cross-sectional shape. hand,
The flat surface constitutes the engagement surface 30B. Also, gear 1
8 has substantially oval notches 25, 25 formed on both sides of the tip surface 20A of the protrusion 20, and the semi-circular portion of the hole 21 formed in the gear 18 has a semi-circular shape. A shaft portion 30A having a circular cross section is fitted.

In this example, the driven side rotating member is constituted by the rotating shaft 30 which is the roller shaft of the developing roller 6, but the driven side rotating member is not limited to the roller shaft of such a developing roller. It is not limited. Alternatively, the shaft portion 30A fitted to the gear 18 and the roller shaft portion integral with the developing roller 6 may be separately configured, and the both may be fixedly connected by a joint or the like.

The end portion side of the rotating shaft 30 extends from the inside of the unit casing 5 so as to be exposed to the outside of the unit casing 5 (FIG. 2), and the shaft portion 30A formed at the end portion of the extending rotating shaft 30. The gear 18 is fitted in.
When the developing unit 4 shown in FIG. 2 is inserted into the main body of the image forming apparatus and the unit is loaded and set so that the developing roller 6 faces the photoconductor 1, the tooth portion 19 of the gear 18 is located on the main body side of the image forming apparatus. The drive gear (not shown) in FIG.

The drive gear is adapted to be driven by the rotation of the main motor on the image forming apparatus main body side through a predetermined rotation transmission means. When the drive gear rotates, a gear 18 meshing with the drive gear is formed. , Is driven to rotate in the counterclockwise direction in FIG. 1 around the central axis line X. At this time, the tip surface 20 of the protrusion 20 formed on the gear 18
A and the flat engagement surface 30B of the shaft portion 30A are engaged with each other, so that the rotation of the gear 18 can be prevented via the shaft portion 30.
The rotary shaft 30 is transmitted to A and rotates together with the gear 18. As a result, the developing roller 6 is rotationally driven in the arrow direction in FIG. In this way, the protrusion 20 and the shaft 3
The rotation of the gear 18 is transmitted to the rotary shaft 30 and the developing roller 6 integrated with the rotary shaft 30 in a state where the gears 0A and 0A are engaged with each other.

As described above, the gear 18 which is an example of the driving side rotating member and the rotating shaft 3 which is an example of the driven side rotating member.
The projection 20 and the shaft 30A provided on the
The engaging portion and the engaged portion, which are engaged with each other and transmit the rotation from the gear 18 to the rotary shaft 30, are respectively configured. Further, in this example, the drive-side rotating member is configured by the gear 18 that is an example of a rotating body having the hole 21 at the center of rotation thereof, and the protrusion 20 provided on the gear 18 is provided.
The front end surface 20A of the shaft is engaged with the engagement surface 30B of the shaft portion 30A so as to enable the rotation transmission between the gear 18 and the rotary shaft 30.

Here, while the gear 18 is rotating integrally with the rotating shaft 30 which is the driven side rotating member, the developing roller 6 is
If the side load torque becomes excessive, the load torque causes the external force applied from the engagement surface 30B of the shaft portion 30A to deform the protrusion 20 by itself as shown in FIG. As a result, the gear 18 only spins, and the gear 1
From 8, the rotation is not transmitted to the rotating shaft 30 which is the driven side rotating member and the developing roller 6. FIG. 4 shows a state in which the protrusion 20 is deformed in the midway of rotation. Further, at this time, not only the projection 20 may be deformed but also the projection 20 may be broken, which also prevents transmission of rotation from the gear 18 to the rotary shaft 30.

As described above, the transmission of this embodiment is provided with the gear 18
And a driven-side rotating member composed of a rotating shaft 30. The former gear 18 and the latter rotating shaft 30 are engaged with each other to move the former gear 18 to the latter gear The rotary shaft 30 is provided with an engaging portion formed of a protrusion 20 for transmitting rotation and an engaged portion formed of a shaft portion 30A. And the protruding portion 20 that constitutes the engaging portion
And the protruding portion 20 of the shaft portion 30A that constitutes the engaged portion.
However, when the load torque of the rotating shaft 30 becomes excessive, the external force applied from the shaft portion 30A, which is the other side of the rotating shaft 30, prohibits transmission of rotation from the gear 18 to the rotating shaft 30,
It is formed so as to deform or break itself.

In such a transmission, the gear 18 itself, which constitutes the drive side rotating member, has a function of detecting an excessive load torque, and the gear 18 itself is provided with such torque detecting means. Can be said to be a thing. Therefore, some special torque detecting means can be dispensed with. Further, the driven-side rotating member can be stopped when an excessive load is generated.

Since a dedicated torque detecting means is not required and a dedicated drive motor is not required to be provided for each unit, the mechanical device using the transmission can be further downsized and its cost can be reduced. Can be further reduced.

When the transmission device of this embodiment is used in the developing unit of the image forming apparatus, foreign matter or the like is caught between the developing roller 6 and the photosensitive member 1 and the load torque on the driven side becomes excessive. In the case of
Since the drive transmission relationship is cut off with the rotation shaft 30 of the developing roller 6 which is the driven side rotation member, it is possible to prevent the occurrence of an accident that damages the photoconductor 1. Further, when the gear 18 is configured to be driven through the idle gear, it is possible to prevent the stud shaft that supports the idle gear and the body side plate to which the stud shaft is attached from being deformed or damaged. Excessive load torque is not transmitted to the drive system on the image forming apparatus main body side, and damage to the transmission elements constituting the drive system can be prevented.

When the load torque of the rotary shaft 30 becomes excessively large, the protrusion 20 is only deformed without breaking, the deformation mode is not only plastic deformation but also elastic deformation. It may be. In the latter case, the deformed protrusion 20 is removed by removing the cause of the overload.
The gear 18 can be used again by restoring the original shape. Further, when adopting the plastically deformed form of the protrusion 20, the gear 18 may be replaced with a new one.

Further, in the embodiment shown in FIGS. 1 to 5, the shaft portion 30A of the rotary shaft 30 has a substantially D-shaped cross section, which is a substantially semicircular portion of the hole 21 of the gear 18. Since the shaft portion 30A is fitted to the end portion, the shape of the shaft portion 30A may be set to be the same as the end portion of the conventionally used rotating shaft. That is, the rotary shaft that has been conventionally used can be used as it is, and the cost thereof can be reduced.
Further, the notches 25, 25 are formed on both sides of the protrusion 20 of the gear 18.
Since the gear 18 is formed, the protrusion 20 can be deformed or fractured as described above with a simple configuration without greatly reducing the strength of the gear 18.

The basic structure of the transmission device shown in FIGS. 6 and 7 is the same as that of the embodiment shown in FIGS. 1 to 5, so that the previous embodiment shown in FIGS. The same reference numerals as those shown in FIG. 1 are attached to the portions corresponding to the respective portions of FIG.

By the way, if the load torque of the driven side rotating member constituted by the rotating shaft 30 becomes excessive, the protruding portion 20 of the gear 18 is deformed or broken as described above. When it breaks, the fragment of the projection 20 is sandwiched between the gear 18 and the shaft 30A, and the rotation of the gear 18 is transmitted to the rotary shaft 30. It is necessary to prevent it from happening.

Here, also by the transmission device of the embodiment shown in FIG. 6, when the excessive load torque is generated, the protrusion 2
It is possible to deform 0 or break it, but notches 25 formed on both sides of the protrusion 20
Since the space of 25 is narrow, the protrusion 20 cannot be freely deformed, or the fragment thereof is not the gear 18 and the shaft portion 30A.
There is a risk of getting caught between.

On the other hand, in the embodiment shown in FIGS. 1 to 5 and 7, the notches 25, 25 formed on both sides of the tip end surface 20A of the protrusion 20 of the gear 18 are formed in the gear 18. It is formed even in a region outside the rotation locus of the outer peripheral portion of the maximum outer diameter of the shaft portion 30A fitted in the formed hole 21. That is, when considering a circle centered on the central axis X of the shaft portion 30A and excluding the engaging surface 30B of the shaft portion 30A, the notch 25 is formed so as to protrude to the outside of the circle. , 25 are formed, and a space 26 corresponding to the protruding portion is secured. When such a space 26 is formed, the rotating shaft 3
When the load torque of 0 becomes excessive, the protrusion 20 is freely deformed as shown in FIG. 4, and the transmission of rotation from the gear 18 to the rotary shaft 30 can be reliably prohibited. Alternatively, at this time, when the protrusion 20 is broken, the paper fragment is
It is possible to prevent the trouble that the broken pieces are caught again between the shaft portion 30A and the gear 18 and the rotation of the gear 18 is transmitted to the shaft portion 30A. This also applies to the embodiments shown in FIGS. 8 to 11 which will be described next. The cutouts 25, 25 shown in FIG. 1 are substantially elliptical, while the cutouts 25, 25 shown in FIG.
25 has a substantially circular shape, and there is a difference in the shape of the cutout.

Next, in the embodiment of the transmission device shown in FIG. 8, the protrusion 20 formed on the gear 18 has the smallest width minimum portion 27, which is the protrusion 20.
Of these, it is the most easily deformed or the most easily broken. Therefore, when the load torque of the rotating shaft 30 becomes excessive, the protrusion 20 starts to deform from the minimum width portion 27 as shown in FIG. 9 or the portion is broken. That is, the minimum width portion 27 induces deformation or breakage of the protrusion 20 of the gear 18 when the load torque of the rotating shaft 30 which is the driven side rotating member becomes excessive. Therefore, when the protrusion 20 is deformed or fractured and the rotation of the gear 18 is not transmitted to the rotary shaft 30, the load torque of the rotary shaft 30 can be made substantially constant at all times. The setting of the load when the transmission of the rotation is prohibited, that is, the setting of the torque resistance is accurate and easy.

Further, in the embodiment shown in FIGS. 8 and 9, the minimum width portion 27 of the protrusion 20 is the rotation locus of the outer peripheral portion of the maximum outer diameter of the shaft portion 30A fitted in the hole 21 of the gear 18. Is also formed on the outer protruding portion 20. That is, as described above, when considering a circle centered on the central axis X of the shaft portion 30A and along the outer peripheral surface excluding the engaging surface 30B, the minimum width portion 27 is formed outside the circle. Is there. According to this configuration, when the protrusion 20 is deformed, it can be freely deformed, and when the protrusion 20 is broken, the broken pieces are reliably stored in the spaces 26, 26 formed by the notches 25, 25. Therefore, it is possible to reliably prevent the problem that the rotation of the gear 18 is transmitted to the rotating shaft 30. Other configurations of the embodiment shown in FIGS. 8 and 9 are substantially the same as those of the embodiment shown in FIG. 1 or 7.

Also in the transmission device shown in FIGS. 10 and 11, the protrusion 20 is provided on the gear 18 which constitutes the driving side rotating member.
However, the thickness T of the protrusion 20 in the central axis X direction of the gear 18 is set to be thinner than the total thickness H of the gear 18 in the central axis X direction. A portion of the hole 21 of the gear 18 other than the portion where the protrusion 20 is located is a circular hole, and its diameter is D (FIG. 11). 10 and 11, the rotary shaft 30 shown in FIG. 9 is omitted, but the engaging surface 30B of the rotary shaft 30 is exactly the same as in FIG.
The shaft portion 30A that engages with the tip end surface 20A of the protruding portion 20 shown in FIG.
Also, it is fitted in the hole 21 of the gear 18 shown in FIG.
The other structure is the same as that of the transmission shown in FIG. In addition, the above-described configuration shown in FIGS.
It can also be applied to the transmission shown in.

As in the transmission shown in FIGS. 10 and 11, the thickness of the protrusion 20 of the gear 18 in the direction of the central axis X is
When the thickness is set to be smaller than the total thickness H of the gear 18 in the same axis X direction, the protrusion 20 can be deformed or broken as described above without lowering the strength of the gear 18. In order to surely deform or break the protrusion 20, it is necessary to reduce the strength of the protrusion 20 so as to obtain such an action. For this purpose, if the strength of the gear 18 is reduced, However, there is a possibility that the strength originally required for the gear 18 may be reduced and the predetermined function may not be achieved. Therefore, in the embodiment shown in FIG. 10 and FIG. 11, the protrusion 20 that is deformed or fractured when an excessive load torque is generated is formed so that it easily deforms or fractures.
The thickness T is set small. By doing so, even if the material of the gear 18 itself is made of a material having high strength, the protrusion 20 can be deformed or broken without any trouble, and the reduction in strength of the gear 18 itself can be prevented. Further, since the gear 18 has a large thickness H in the direction of the central axis X, the strength thereof can be kept high only from the shape thereof, and the projection 20 can be surely secured when a predetermined torque is generated. It can be deformed or broken.

Further, when various gears 18 having different thicknesses T of the protrusions 20 are prepared and the gears 18 suitable for the target mechanical device are used, when the protrusions 20 are deformed or broken. The load torque of the rotary shaft 30 can be freely set.

Similarly, the thickness of the protrusion 20 shown in FIGS. 3 and 8 in the direction of the central axis X is made constant, and then the protrusion 20 is formed.
By changing the width W of each of the widths W, the protrusion 20 can be deformed according to the magnitude of the load torque with respect to each width W. FIG. 12 shows the correlation characteristic between the width W of the protrusion 20 shown in FIG. 3 and the torque (torque resistance) when rotation is no longer transmitted from the gear 18 to the rotary shaft 30, and when the width W increases, The torque resistance increases in proportion to. By preparing various gears having different widths W, it is possible to select the load torque at which the drive transmission relationship is to be cut. This is the same in each of the embodiments described above and each of the embodiments described later.

As described above, by changing the thickness T and the width W of the protrusion 20 of the gear 18, the protrusion 2 can be changed.
Since the easiness of deformation or breakage of 0 can be freely set, even if the gear 18 is configured as a single member made of a single material, the original description can be obtained. Protrusion 2
In order to easily deform or break only 0 and increase the strength of the other gear parts, it is possible to avoid the troublesome thing of forming both by separate members and forming these by integrating them. Of.

In each of the embodiments described above, when the load torque of the rotating shaft 30 which is the driven side rotating member becomes excessive, the engaging portion 20 on the gear 18 side which is an example of the driving side rotating member is deformed. , Or is configured to break, on the contrary, the engaged portion on the side of the driven side rotating member is deformed or broken, whereby the driving side rotating member and the driven side rotating member. May be configured to rotate around each other.

For example, as shown in FIG. 13, a circular hole 21 formed in the central portion of a drive-side rotating member composed of a gear 18 having teeth 19 on the entire circumferential surface is provided with a notch 120 as an engaging part. To form. On the other hand, a rotating shaft 30 that is an example of a driven-side rotating member, has a substantially semicircular notched shaft portion 30A.
Is fitted into the hole 21 concentrically with the gear 18, and the projection 28 protruding from the shaft portion 30A is fitted into the notch 120 formed in the gear 18. In this example, the protrusion 2
The shaft portion 30A having 8 constitutes the engaged portion of the driven side rotating member.

When the gear 18 rotates about its central axis, for example in the counterclockwise direction in FIG. 5, its rotation is normally transmitted to the rotating shaft 30 via the notches 120 and the protrusions 28 which are engaged with each other. The rotation shaft 30 also rotates in the counterclockwise direction. On the other hand, when the load torque of the rotary shaft 30, that is, the load torque of the developing roller not shown in FIG. 13 becomes excessive, as shown in FIG.
8 is elastically or plastically deformed, or is broken to form a notch 12
It is prohibited to transmit the rotation of the gear 18 to the rotating shaft 30 by deviating from 0.

In the embodiment shown in FIGS. 1, 6, 7, 8 and 10, when the load torque of the rotating shaft 30 becomes excessive, the protrusion 20 constituting the engaging portion is deformed, In the example shown in FIGS. 13 and 14, the protrusion 28 that constitutes the engaged portion is used.
However, it is also possible to prevent the rotation of the driving side rotating member from being transmitted to the driven side rotating member by deforming both of them. In short, at least one of the engaging part and the engaged part prohibits transmission of rotation from the driving side rotating member to the driven side rotating member when the load torque of the driven side rotating member becomes excessive. In order to do so, it suffices if it is formed so as to be deformed by the external force applied from the other side.

In FIG. 2, the developing unit 4 is provided with two rotary members, a developing roller 6 and a developer stirring and supplying roller 7, which are driven collectively. The collective drive may be provided with the transmission of each of the above-described embodiments.

For example, as shown in FIG. 15, a gear 18 constituting a driving side rotating member is provided outside the unit casing 5, and the gear 18 has a rotating shaft 1 which is a driven side rotating member.
Engage 30. The gear 18 has exactly the same structure as the gear 18 in each of the above-described embodiments, and has a rotating shaft 130.
Also, the rotary shaft 30 including the shaft portion 30A in each of the above-described embodiments is configured in exactly the same manner. The gear 18 is rotationally driven clockwise by a drive gear (not shown) on the main body of the image forming apparatus when viewed from the direction of arrow a, and the rotary shaft 130 is rotated accordingly, and an idle gear fixedly mounted on the rotary shaft 130. Both gears 23, 24 are rotationally driven via 22.

By the rotation of both gears 23, 24, the developing roller 6 coaxially integrated with each gear 23, 24 and the developer agitation supply roller 7 are rotationally driven in the directions of the arrows in FIG. Developing roller 6 and developer stirring and supplying roller 7
If either or both of the load torques become excessive, the protrusion 20 (FIG. 1) or the protrusion 28 (FIG. 1) of the gear 18
3) is deformed or broken as described above, and the developing roller 6
And the rotation of the developer agitation supply roller 7 are both stopped.

As described above, the driving side rotating member and the driven side rotating member of the transmission device may be provided in a portion for collectively driving a plurality of rotating members provided in the image forming process unit of the image forming apparatus. By doing so, it is possible to stop only the rotating member of the unit that has become overloaded. Then, the unit is taken out of the main body of the image forming apparatus,
The unit can be immediately activated by simply replacing the deformed gear 18 with a new one or removing the cause of the overload. This also leads to improvement of maintenance serviceability.

On the other hand, for example, the driving side rotating member including the gear 18 is provided in each of the plurality of driven side rotating members provided in the image forming process unit of the image forming apparatus to configure the transmission device. May be. For example, the gear 18 is attached to each of the rotating shafts of the developing roller 6 and the developer stirring and supplying roller 7 which are the rotating members of the developing unit 4 shown in FIG. By doing so, for each rotating member, only the overloaded rotating member can be stopped independently from the other rotating members, and the overloaded rotating member is deformed or damaged. Can be prevented.

In each of the embodiments described above, the driving side rotating member is constituted by the rotating body composed of the gear 18, but instead, such rotating body may be constituted by a pulley or a friction wheel. Further, in the illustrated embodiments,
The side of the rotating body including the gear 18 is used as the driving side rotating member, and the rotating shafts 30 and 130 fitted thereto are configured as the driven side rotating members. One may be configured as a driven side rotating member, and the rotating shafts 30 and 130 fitted thereto may be configured as a driven side rotating member. For example, the rotation of the rotary shaft 30 shown in FIG. 1 is transmitted to the gear 18. At that time, the shaft portion 30A shown in FIG.
The protruding portion 20 of 8 constitutes the engaged portion of the driven side rotating member. The engaging part and the engaged part described above are opposite. As described above, one of the driving-side rotating member and the driven-side rotating member is composed of a rotating body having a hole in its rotation center, and the other is composed of a rotating shaft having a shaft portion fitted in the hole. The body is composed of the gear 18 described in detail above, or a pulley, a friction wheel, or the like.

Further, the above-mentioned engaging portion or engaged portion is
When the driven-side rotating member has an excessive load torque, it is only deformed, and the engaging portion or the engaged portion is made of, for example, synthetic resin so as not to generate a fragment during the deformation. Therefore, it is possible to more reliably prevent a secondary defect due to the fragment. For example, such a fragment
If it falls on the registration roller pair 9 (Fig. 2),
When the rollers are bitten between the rollers, the rollers may be damaged or the rollers may not rotate, but if the engaging portion or the engaged portion is made of a material that does not cause fragmentation,
Such a problem can be prevented.

The present invention can also be applied to transmission devices in various mechanical devices other than image forming devices.

[0059]

According to the first aspect of the present invention, with the extremely simple configuration, when the load torque of the driven side rotating member becomes excessive, the driven side rotating member can be automatically stopped. Therefore, it is possible to prevent deformation or damage of the drive system or the like on the main body side of the mechanical device that drives the driven-side rotating member, and no special torque detection means is required, so a mechanical device that uses a transmission device. Can be miniaturized and its cost can be reduced. Moreover, it is possible to prevent the strength of the rotating body from being lowered and to simplify the configuration thereof to obtain the above-described effects.

[0060]

[0061]

According to the second aspect of the present invention, the protrusion can be surely deformed, or when it breaks, the broken pieces enter between the rotating body and the rotating shaft,
It is possible to reliably prevent the problem that the rotation is transmitted between the two.

According to the third aspect of the present invention, the driven side rotating member can be automatically stopped when the load torque of the driven side rotating member becomes excessive by the extremely simple structure. It is possible to prevent deformation and damage of the drive system on the machine body side that drives the driven side rotating member,
Further, since the dedicated torque detecting means is not required, the mechanical device using the transmission device can be downsized and its cost can be reduced. Moreover, the portion where the protrusion deforms or breaks becomes constant, and the magnitude of the load torque of the driven-side rotating member when the protrusion deforms or breaks can be correctly determined.

According to the structure described in claim 4, the protrusion can be surely deformed, or when the protrusion is broken, the broken pieces enter between the rotating body and the rotating shaft,
It is possible to reliably prevent the problem that the rotation is transmitted between the two.

According to the fifth aspect of the invention, the driven side rotating member can be automatically stopped when the load torque of the driven side rotating member becomes excessive by the extremely simple structure. It is possible to prevent deformation and damage of the drive system on the machine body side that drives the driven side rotating member,
Further, since the dedicated torque detecting means is not required, the mechanical device using the transmission device can be downsized and its cost can be reduced. Moreover, the protrusion can be reliably deformed or broken without reducing the strength of the rotating body.

[0066]

[0067]

[0068]

[Brief description of drawings]

FIG. 1 is a partial cross-sectional front view showing a transmission device according to an embodiment of the present invention.

FIG. 2 is a schematic configuration diagram of an image forming apparatus using the above transmission device.

FIG. 3 is a front view of a gear that is an example of a drive-side rotating member that is included in the transmission device.

FIG. 4 is a view showing a state in which the protrusion of the gear is deformed, FIG.
It is a front view similar to.

FIG. 5 is a perspective view of a rotating shaft having a shaft portion.

FIG. 6 is a partial cross-sectional front view showing a transmission device of another embodiment.

FIG. 7 is a partial cross-sectional front view showing a transmission device of still another embodiment.

FIG. 8 is a partial sectional front view showing a power transmission device of still another embodiment.

FIG. 9 is a partial cross-sectional front view showing a state in which the protrusion shown in FIG. 8 is deformed.

FIG. 10 is a partial cross-sectional front view showing a transmission device of still another embodiment.

11 is a vertical cross-sectional view of the gear shown in FIG.

FIG. 12 shows the width of the engaging portion shown in FIG.
It is a characteristic view which shows how a torque resistance changes.

FIG. 13 is a partial cross-sectional front view showing a transmission device of still another embodiment.

14 is a partial cross-sectional view showing a state where the protrusion shown in FIG. 13 is deformed.

FIG. 15 is a schematic configuration diagram showing an example in which a transmission device is provided in a collective drive unit of a plurality of rotating members.

[Explanation of symbols]

20 protrusions 20A tip surface 21 holes 25 notches 27 Minimum width 30 rotation axis 30A shaft 30B engagement surface H thickness T thickness X center axis

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) F16H 19/00-37/16 F16H 51/00-55/30

Claims (5)

(57) [Claims] 1. A driving side rotating member and a driven side rotating member, wherein the former driving side rotating member and the latter driven side rotating member are engaged with each other to form the former driving side rotating member. A transmission device provided with an engaging part and an engaged part for transmitting rotation from a member to the latter driven side rotating member, respectively, and an engaging part,
At least one of the engaged parts is added from the other side so as to prohibit the transmission of rotation from the driving side rotating member to the driven side rotating member when the load torque of the driven side rotating member becomes excessive. A shaft which is formed so as to deform or break by itself by an external force applied, and one of the driving side rotating member and the driven side rotating member is a rotating body having a hole in its rotation center, and the other is a shaft fitted in the hole. Consisting of a rotating shaft having a section,
The rotating body has a protrusion protruding toward the center of the hole, and the tip of the protrusion is provided on the shaft so as to enable rotation transmission between the rotating body and the rotation shaft. An engaging surface that engages with the surface is formed, one of the protrusion and the engaging surface constitutes the engaging portion, and the other constitutes the engaged portion. The transmission is characterized in that notches are formed on both sides of the tip end surface of the projection. 2. The transmission device according to claim 1, wherein the notch is formed even in a region outside a rotation locus of an outer peripheral portion having a maximum outer diameter of the shaft portion fitted in the hole. 3. A driving-side rotating member having a driving-side rotating member and a driven-side rotating member, wherein the former driving-side rotating member and the latter driven-side rotating member are engaged with each other to form the former driving-side rotating member. A transmission device provided with an engaging part and an engaged part for transmitting rotation from a member to the latter driven side rotating member, respectively, and an engaging part,
At least one of the engaged parts is added from the other side so as to prohibit the transmission of rotation from the driving side rotating member to the driven side rotating member when the load torque of the driven side rotating member becomes excessive. A shaft which is formed so as to deform or break by itself by an external force applied, and one of the driving side rotating member and the driven side rotating member is a rotating body having a hole in its rotation center, and the other is a shaft fitted in the hole. Consisting of a rotating shaft having a section,
The rotating body has a protrusion protruding toward the center of the hole, and the tip of the protrusion is provided on the shaft so as to enable rotation transmission between the rotating body and the rotation shaft. An engaging surface that engages the surface is formed, and one of the protrusion and the engaging surface constitutes the engaging portion, and the other constitutes the engaged portion, Is a transmission device having a minimum width portion that induces deformation or breakage of the protrusion when the load torque of the driven rotary member becomes excessive. 4. The transmission device according to claim 3, wherein the minimum width portion is formed on a projection portion outside the rotation locus of the outer peripheral portion of the maximum outer diameter of the shaft portion fitted in the hole. 5. A driving side rotating member and a driven side rotating member, wherein the former driving side rotating member and the latter driven side rotating member are engaged with each other to form the former driving side rotating member. A transmission device provided with an engaging part and an engaged part for transmitting rotation from a member to the latter driven side rotating member, respectively, and an engaging part,
At least one of the engaged parts is added from the other side so as to prohibit the transmission of rotation from the driving side rotating member to the driven side rotating member when the load torque of the driven side rotating member becomes excessive. A shaft which is formed so as to deform or break by itself by an external force applied, and one of the driving side rotating member and the driven side rotating member is a rotating body having a hole in its rotation center, and the other is a shaft fitted in the hole. Consisting of a rotating shaft having a section,
The rotating body has a protrusion protruding toward the center of the hole, and the tip of the protrusion is provided on the shaft so as to enable rotation transmission between the rotating body and the rotation shaft. An engaging surface that engages with the surface is formed, one of the protrusion and the engaging surface constitutes the engaging portion, and the other constitutes the engaged portion. The thickness of the protrusion in the direction of the central axis of is set to be thinner than the total thickness of the rotating body in the direction of the central axis.