JP2001289311A - Resin-made gear and image forming device provided with the same gear and resin-made rotation transmission means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin-made gear having satisfactory rotation transmission accuracy. SOLUTION: A first peripheral direction rib 10 and a second peripheral direction rib 11 are coaxially formed on a web 5 on an inner peripheral side of a tooth part 8. Moreover, the rigidity of the web 5 is increased by ribs 14, 12, 15 in the radial direction. Since the rib 14 in the radial direction is formed to extend obliquely in the direction reverse to the direction of rotation, a resistance force preventing the displacement of the second peripheral direction rib 11 so as to deviate in the direction of rotation relative to a shaft support part 4 is generated in the rib 14 in the radial direction, even if the second peripheral direction rib 11 attempts to displace due to torque fluctuation acting when rotation is transmitted, so that the displacement of the second peripheral direction rib 14 so as to deviate in the direction of rotation relative to the shaft support part 4 can be effectively suppressed and dispersion in rotary angular velocity of the second peripheral direction rib 14, the shaft support part 4, the tooth part 8 and the shaft support part 4 can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin gear widely used for a power transmission mechanism of a copying machine, a printer, a facsimile, an automobile part and the like, and a copying machine using the resin gear to improve image quality. The present invention relates to an image forming apparatus such as a printer and a printer. Further, the present invention relates to a resin gear and a resin pulley as a resin rotation transmitting means.

[0002]

2. Description of the Related Art Conventionally, resin gears have been used in power transmission mechanisms for copying machines, automobile parts, and the like for the purpose of reducing the cost of parts, reducing the weight, and reducing operating noise. This resin gear is formed into a predetermined shape by injection molding, and the shape is devised so that the tooth profile accuracy and strength match the intended use.

[0003] For example, in an image forming apparatus such as a color copying machine, a clear high-quality color image is formed.
As a resin gear for driving the photosensitive member, a resin helical gear having a high meshing ratio is used, and the shape of the resin helical gear is variously devised. The resin helical gear is connected to a photoconductor driving motor (driving means), and the rotational force of the photoconductor driving motor is smoothly transmitted to the photoconductor via the resin helical gear. In addition, since the photosensitive member is smoothly and accurately rotated, printing defects such as color misregistration can be effectively prevented.

FIGS. 16 and 17 show a resin helical gear 100 used in such an image forming apparatus. The resin helical gear 100 shown in these figures has a shaft support portion 103 having a shaft hole 102 fitted so as to be able to rotate integrally with a photoconductor drive shaft 101, and a shaft support portion 103.
Rim 105 with teeth 104 located radially outwardly of
And a thin web 106 that connects the shaft support 103 and the rim 105. The resin helical gear 100 is a web 1
In order to prevent deformation of the first and second circumferential ribs 1 and 2 on the inner side of the rim 105 and on both side surfaces of the web 106,
07, 108 are formed on both sides of the web 106 between the shaft support 103 and the second circumferential rib 108.
03 and the radial rib 1 connected to the second circumferential rib 108
10 are formed radially, and are provided on both side surfaces of the web 106 between the first circumferential rib 107 and the second circumferential rib 108 so as to connect to the first circumferential rib 107 and the second circumferential rib 108. The direction rib 111 is formed radially.

[0005] The resin helical gear 100 having such a configuration is used.
Since the radial ribs 110 and 111 are not connected to the rim 105, the rigidity of the web 106 can be increased without impairing the roundness of the rim 105 having the teeth 104. Since the resin helical gear 100 is formed into the shape shown in FIGS. 16 and 17 by injection molding, the longer the thickness of the resin, the longer the cooling in the cavity takes. The amount of shrinkage deformation increases. Accordingly, the resin helical gear 100 having such a shape is provided with the web 106
Is thicker, the thickness of the connecting portion between the web 106 and the rim 105 becomes larger, and the amount of contraction deformation inward in the radial direction of the connecting portion between the web 106 and the rim 105 becomes larger than that of the other portion of the rim 105. As a result, the tooth profile accuracy deteriorates. Also, as shown in FIG. 18, when the radial rib 112 is connected to the rim 113, the thickness of the connecting portion between the radial rib 112 and the rim 113 is increased, and the connection between the radial rib 112 and the rim 113 is increased. The amount of contraction deformation of the portion inward in the radial direction becomes larger than that of the other portion of the rim 113 (see the dotted line portion in the figure), and the roundness is reduced.
Therefore, the conventional resin helical gear 100 shown in FIGS.
The web 1 is adjusted so that the teeth 104 have the desired accuracy.
06 to the first and second circumferential ribs 10
7 and 108 and radial ribs 110 and 111.

[0006]

In recent years, image forming apparatuses such as color printers and color copiers have been required to be able to perform more vivid color printing than conventional examples with the development of image processing technology. ing. In order to meet such a demand, it is necessary to rotate the photoconductor more smoothly and with higher precision than before, and to improve the accuracy of image formation on the photoconductor. Here, it is the accuracy of the resin helical gear that greatly affects the rotation accuracy of the photoconductor, as described above.

However, the conventional resin helical gear 100
As shown in FIG. 19, the rim 105 having the teeth 104 is
, The deformation between the shaft support 103 and the second circumferential rib 108 is larger than that of the other parts, and the radial direction formed on the outer periphery of the shaft support 103 is particularly large. Since the rib 110 is deformed as shown by the dotted line, the rotation transmitted from the photoconductor driving motor (not shown) to the resin helical gear 100 and the rotation transmitted from the resin helical gear 100 to the photoconductor driving shaft 101 are transmitted. It has been found that this rotation causes a shift, and that the shift in the rotation causes a deterioration in image quality such as color shift.

Accordingly, the present invention is to improve the dynamic accuracy (rotation transmission accuracy) of the resin helical gear by devising the shape of the resin helical gear, which greatly affects the rotation accuracy of the photoconductor. It is another object of the present invention to further improve the image quality of an image forming apparatus.

[0009]

According to a first aspect of the present invention, there is provided a substantially cylindrical tooth portion formed radially outward, and a radially inward portion formed around the center of rotation of the tooth portion. The present invention relates to a resin gear provided with a shaft support portion formed as described above, and a thin plate-shaped web connecting the shaft support portion and the tooth portion.
A circumferential rib is formed on the web inside the tooth portion and at a position concentric with the tooth portion. Also, the radial rib connecting the circumferential rib and the shaft support portion along the side surface of the web is directed obliquely outward from the outer periphery of the shaft support portion so as to receive a compressive force at the start of power transmission. A plurality is formed.

According to a second aspect of the present invention, there is provided a substantially cylindrical tooth formed radially outward, and a shaft support formed radially inward so as to be centered on the rotation center of the tooth. The present invention relates to a resin gear provided with the shaft supporting portion and a thin plate-shaped web connecting the tooth portion. A circumferential rib is formed on the web inside the tooth portion and at a position concentric with the tooth portion. Also, a plurality of radial ribs connecting the circumferential rib and the shaft support portion along the side surface of the web are formed so as to extend obliquely from the outer periphery of the shaft support portion in a direction opposite to the normal rotation direction. One radial rib,
A plurality of second radial ribs are formed so as to extend obliquely from the outer periphery of the shaft support in the reverse rotation direction and the reverse direction.

According to a third aspect of the present invention, there is provided a substantially cylindrical tooth portion formed radially outward, and a shaft support portion formed radially inward so as to be centered on the rotation center of the tooth portion. The present invention relates to a resin gear provided with the shaft supporting portion and a thin plate-shaped web connecting the tooth portion. A first circumferential rib is formed on the web inside the tooth portion and concentric with the tooth portion, and a second circumferential rib is formed inside the first circumferential rib and at a concentric position. A circumferential rib is formed. The second circumferential rib and the first circumferential rib are connected to each other along the side surface of the web by the radial rib so that the second circumferential rib receives a compressive force at the start of power transmission.
Are formed obliquely outward from the outer periphery of the circumferential rib.

According to a fourth aspect of the present invention, there is provided a substantially cylindrical tooth formed radially outward, and a shaft support formed radially inward so as to be centered on the rotation center of the tooth. The present invention relates to a resin gear provided with the shaft supporting portion and a thin plate-shaped web connecting the tooth portion. A first circumferential rib is formed on the web inside the tooth portion and concentric with the tooth portion, and a second circumferential rib is formed inside the first circumferential rib and at a concentric position. A circumferential rib is formed. A radial rib connecting the second circumferential rib and the first circumferential rib along a side surface of the web is oblique from the outer periphery of the second circumferential rib in a direction opposite to the normal rotation direction. A plurality of first radial ribs are formed so as to extend in a direction, and a plurality of second radial ribs are formed so as to extend obliquely from the outer periphery of the second circumferential rib in a direction opposite to the reverse rotation direction. Has become.

According to a fifth aspect of the present invention, there is provided a substantially cylindrical tooth portion formed radially outward, and a shaft support portion formed radially inward so as to be centered on the rotation center of the tooth portion. The present invention relates to a resin gear provided with the shaft supporting portion and a thin plate-shaped web connecting the tooth portion. The web has a radial rib connecting the tooth portion and the shaft support along a side surface of the web. The radial rib obliquely extends from the outer periphery of the shaft support so as to receive a compressive force at the start of power transmission. A plurality is formed toward the direction.

According to a sixth aspect of the present invention, there is provided an image comprising: the resin gear according to any one of the first to fifth aspects; and a driving unit for rotating the photosensitive member via the resin gear. The present invention relates to a forming apparatus. In this image forming apparatus, the rotation center of the resin gear and the rotation center of the rotary drum are coaxially located, and the resin gear and the rotary drum are connected so as to be able to rotate integrally. Features.

According to a seventh aspect of the present invention, there is provided a substantially cylindrical tooth portion formed radially outward, and a shaft support portion formed radially inward so as to be centered on the rotation center of the tooth portion. A resin having a thin plate-shaped web connecting the shaft support portion and the tooth portion, and a radial rib radially formed on the web so as to extend from the shaft support portion toward the tooth portion. The present invention relates to a rotation transmitting means. The radial rib is formed so as to be obliquely outward from the shaft support so as to receive a compressive force at the start of power transmission.

[0016]

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

(Resin Helical Gear) [First Embodiment] FIGS. 1 to 3 show a resin helical gear 1 as a resin gear according to a first embodiment of the present invention.
It shows. FIG. 1 is a front view (left side view of FIG. 2) of the resin helical gear 1. FIG. 2 is a cross-sectional view of the resin helical gear 1 cut along the line AA in FIG. FIG. 3 is a rear view (a right side view of FIG. 2) of the resin helical gear 1.

As shown in these figures, a resin helical gear 1 is injection-molded using a resin material such as polyacetal or fluorine-containing polycarbonate, and is engaged with a photoconductor drive shaft 2. A shaft support 4 having a shaft hole 3 formed therein, a web 5 formed substantially at the center of the shaft support 4 in the axial direction, and formed on the outer surface of the shaft support 4, and the web 5 And a substantially annular rim 6 connected to the rim 6. Further, teeth 7 are formed on the outer peripheral side of the rim 6 formed concentrically with the shaft support 4. The rim 6 and the teeth 7 constitute a substantially cylindrical tooth portion 8.

Inside the rim 6 and on both sides of the web 5, annular first circumferential ribs 10 are formed concentrically with the rim 6, respectively. Also, the first circumferential rib 10
Between the shaft support 4 and both side surfaces of the web 5,
Annular second circumferential rib 1 concentric with the circumferential rib 10 of FIG.
1 are formed respectively. Also, the first circumferential rib 1
0 and the second circumferential rib 11
A plurality of radial ribs 12 are radially formed on both side surfaces of the web 5 between the zero and the second circumferential rib 11.

The second circumferential rib 11 and the cylindrical outer cylindrical portion 13 of the shaft support 4 are connected to the second circumferential rib 1.
The web 5 is connected to the outer cylindrical portion 13 of the shaft support 4 by a plurality of radial ribs 14 respectively formed on both side surfaces of the web 5. The radial rib 14 connecting the second circumferential rib 11 and the outer cylindrical portion 13 of the shaft support 4 is formed so as to be inclined in a direction opposite to the rotation direction of the resin helical gear 1. When a clockwise force in FIG. 1 acts on the teeth (at the start of power transmission), it receives a compressive force to prevent the relative rotation between the second circumferential rib 11 and the shaft support 4. Is caused.

On both side surfaces of the web 5 between the first circumferential rib 10 and the rim 6, radial ribs 15 having a width dimension and a height dimension which do not adversely affect the tooth profile accuracy are formed on the first circumferential rib. A plurality of radial ribs are formed so as to connect the directional rib 10 and the rim 6. As a result, the rigidity of the web 5 between the first circumferential rib 10 and the rim 6 is increased by the plurality of radial ribs 15. Note that the radial rib 15 is formed to have a smaller width dimension W and a smaller height dimension H than the other radial ribs 12 and 14.

Here, each of the radial ribs 12, 14, 15
Are formed so as to be shifted in the circumferential direction. That is, the second
The outer peripheral end of the radial rib 14 is connected between the connecting portions between the circumferential rib 11 and the radial ribs 12, 12, and the diameter between the connecting portions between the first circumferential rib 10 and the radial ribs 15, 15. The outer peripheral ends of the directional ribs 12 are connected. This is because if the radial ribs 14, 12, 15 are located on the same straight line, the amount of contraction in the radial direction after injection molding becomes large, which may adversely affect the roundness of the tooth portion 8. Because. Also, each circumferential rib 10, 11 and each radial rib 1
2, 14, 15 are formed at symmetrical positions on both side surfaces of the web 5, so that the shrinkage deformation after injection molding does not shift between one side of the web 5 and the other side of the web 5, It is devised to enable high precision injection molding.

The shaft supporting portion 4 has an inner cylindrical portion 16 having a shaft hole 3 fitted into a photosensitive member driving shaft 2 extending from a photosensitive member (not shown).
And an outer cylinder portion 13 formed concentrically with the inner cylinder portion 16.
The outer cylinder portion 13 and the inner cylinder portion 16 are
7 are connected. On one side (left side in FIG. 2) of the web 17, a key groove 20 that engages with the rotation stop of the photoconductor drive shaft 2 is formed in a substantially cross shape.
On one side surface of the web 5, a radial rib 21 for connecting the inner cylindrical portion 16 and the outer cylindrical portion 13 in the radial direction is formed between the respective key grooves 20 and 20. The circumferential ribs 22 intersecting with the ribs 21 are provided in the respective keyways 20, 20.
It is formed between them. On the other hand, on the other side (the right side in FIG. 2) of the web 5 of the shaft support 4, a radial rib 23 connecting the inner cylindrical portion 16 and the outer cylindrical portion 13 in the radial direction is provided with a resin helical gear. 1 is formed so as to be inclined in a direction opposite to the rotation direction. A circumferential rib 24 intersecting the plurality of radial ribs 23 is formed on the other side surface of the web 17 of the shaft support 4. Here, the outer peripheral end of the radial rib 23 is connected to the outer cylindrical portion 13 so as to be located between the inner peripheral ends of the radial ribs 14 on the radially outer side. This is because when the outer peripheral end position of the radial rib 23 and the inner peripheral end position of the radial rib 14 are overlapped, these radial ribs 23,
The connection between the outer tube part 14 and the outer cylinder part 13 becomes thicker than the other parts,
This is because a difference occurs in the cooling rate after injection molding, and high-precision molding becomes difficult. As shown in FIG. 2, the web 17 of the shaft support 4 is formed at a position closer to one side surface where the key groove 20 is formed. This is because the rotation stopper 18 of the photoconductor drive shaft 2 is engaged with the key groove 20 of the shaft support portion 4 and a large torque acts on one side surface of the shaft support portion 4. This is because it is necessary to ensure the strength of one side surface of the portion 4.

The resin helical gear 1 having the structure described above
Are the rim 6, the webs 5, 17, the circumferential ribs 10, 11,
The outer cylindrical portion 13 and the inner cylindrical portion 16 are formed to have substantially the same thickness, and the thickness of each of the radial ribs 12, 14, 21, 23 is equal to or smaller than the thickness of the circumferential ribs 10, 11. It is formed so that the cooling rate after injection molding is substantially the same in each part, so that the shrinkage and deformation after injection molding are made uniform, and molding is performed with high precision. The circumferential rib 2
2 and 24 are formed to have substantially the same dimensions as the width and height of the radial ribs 15 and are designed to increase rigidity without impairing the molding accuracy of the shaft support 4. I have.

The resin helical gear 1 of the present embodiment
As described above, since the thickness is sufficiently reduced, the weight can be reduced, the amount of shrinkage deformation after injection molding is reduced, and the entire shape including the tooth portions 8 can be formed with high precision. it can. However, the resin helical gear 1 of the present embodiment
The circumferential ribs 10, 1 can be removed even if the thickness is reduced as described above.
1 and the radial ribs 12, 14, 15 are formed on the side surfaces of the web 5, so that the strength of the web 5 is sufficiently ensured. The power can be reliably transmitted to the photoconductor drive shaft 2 engaged with the section 4.

In addition, the resin helical gear 1 of the present embodiment is provided between the second circumferential rib 11 and the shaft support 4 where the displacement in the rotational direction during rotation transmission is greatest (FIG. 19). ), And a radial rib 14 inclined in a direction opposite to the rotation direction is formed, and this radial rib 14 prevents the rotational deformation between the second circumferential rib 11 and the shaft support 4 in the rotation direction. Because such a reaction force is generated, the tooth portion 8
The amount of displacement (rotational phase difference) in the rotational direction between the shaft support 4 and the shaft support 4 can be reduced. Therefore, according to the resin helical gear 1 of the present embodiment, the rotation transmission accuracy (dynamic accuracy) is improved, and the photoconductor drive shaft 2 can be rotated smoothly and with high accuracy. .

In the above-described embodiment, each connection portion corner, such as the shape of the connection portion corner between the radial ribs 12 and 14 and the circumferential rib 11 and the shape of the connection portion corner between the radial rib 14 and the outer cylindrical portion 13, etc. Has an R-plane shape to improve moldability and releasability and to avoid stress concentration.

In the resin helical gear 1 according to the above-described embodiment, the radial rib 12 between the first circumferential rib 10 and the second circumferential rib 11 is replaced with the second circumferential rib. 11
Similarly to the radial ribs 14 between the shaft and the shaft support 4, the resin helical gear 1 may be inclined in the direction opposite to the rotation direction. The resin helical gear 1 configured as described above can further improve the rotation transmission accuracy as compared with the above embodiment.

Further, in the resin helical gear 1 according to the above-described embodiment, all of the radial ribs 12 and 15 are the same as the radial rib 14 between the second circumferential rib 11 and the shaft support 4. Alternatively, the resin helical gear 1 may be inclined in a direction opposite to the rotation direction. The resin helical gear 1 configured as described above can further improve the rotation transmission accuracy as compared with the above embodiment.

In the case where the resin helical gear 1 according to the above embodiment is used as an idle gear, only the radial ribs 12 are opposite to the rotational direction of the resin helical gear 1. May be inclined in the direction of.

Further, the resin helical gear 1 according to the above-described embodiment has been exemplified to be engaged with the photoreceptor drive shaft 2 so as to be integrally rotatable. However, the present invention is not limited to this. (Not shown) can also be used in a mode in which it is rotatably engaged.

Further, in the above-described embodiment, the resin helical gear 1 for outputting the power input from the tooth portion 8 from the shaft support portion 4 is exemplified. The resin helical gear 1 output from the portion 8 is formed such that the radial ribs 14 are inclined in the opposite direction to the radial ribs 14 of the above embodiment. That is, the resin helical gear 1 that outputs the power input from the shaft support portion 4 through the tooth portions 8 has the radial ribs 14 extending obliquely from the outer periphery of the shaft support portion 4 in the same direction as the rotation direction. A plurality is formed. The resin helical gear 1 formed in this manner has a reaction force such that the radial rib 14 receives a compressive force at the start of power transmission and prevents the shaft support 4 and the tooth 8 from moving in the rotational direction. And the same effect as in the above embodiment can be obtained. In addition, as described above, the resin helical gear 1 that outputs the power input from the shaft support portion 4 from the tooth portion 8 is formed by tilting the radial ribs 12 and 15 in the same direction as the radial rib 14. You may make it.

[Second Embodiment] FIGS. 4 to 6 show a resin helical gear 31 according to a second embodiment of the present invention. A resin helical gear 31 integrally formed with 31a and 31b is shown. FIG. 4 is a front view (left side view) of the resin helical gear 31. FIG. 5 is a cross-sectional view taken along line BB of FIG. FIG. 6 is a rear view of the resin helical gear 31 (a right side view of FIG. 5).

The resin helical gear 31 of the present embodiment is
A first rim 33 having teeth 32 formed on its outer periphery;
An annular first circumferential rib 34 formed concentrically with the first rim 33 inside the rim 33, and formed concentrically with the first rim 33 inside the first circumferential rib 34. The second
And a cylindrical shaft support portion 36 formed inside the second circumferential rib 35.
3. The first circumferential rib 34 and the second circumferential rib 35 are connected by a thin plate-shaped first web 37, and the second circumferential rib 35 and the shaft support portion 36 are formed of a thin plate-shaped second web 37. Web 3
8 are connected. The first circumferential rib 34 and the second circumferential rib 35 have the same dimension (L) as the tooth width (L1).
1 = L2 = L3). The first web 37 is formed substantially at the center in the tooth width direction.
Is formed so as to be orthogonal to the rim 33, the first circumferential rib 34, and the second circumferential rib 35. Further, the second web 38 is formed on the back side end of the second circumferential rib 35 (FIG. 5).
The outer peripheral end is connected to the (middle right end), the inner peripheral end is connected to the outer periphery of the shaft support portion 36, and is orthogonal to the second circumferential rib 35 and the shaft support portion 36. A second rim 41 having teeth 40 on the outer periphery is formed concentrically with the shaft support portion 36 on the rear side surface of the second web 38. The teeth 32 and the first rim 33 form a first tooth portion 42, and the teeth 40 and the second rim 41 form a second tooth portion 43.

On both sides of the first web 37 between the first rim 33 and the first circumferential rib 34, the first rim 33
A plurality of radial ribs 44 are formed in the circumferential direction to radially connect the first circumferential rib 34 and the first circumferential rib 34. The first circumferential rib 34 and the second circumferential rib 35 are provided on both side surfaces of the first web 37 between the first circumferential rib 34 and the second circumferential rib 35. A plurality of radial ribs 45 connected in the circumferential direction are formed in the circumferential direction. Also, the second circumferential rib 35
The side of the second web 38 between the shaft support 36 and
A radial rib 46 is formed to radially connect the second circumferential rib 35 and the shaft support 36. Further, on a side surface of the second web 38 between the second rim 41 and the shaft support portion 36, a radial rib 47 that connects the second rim 41 and the shaft support portion 36 in a radial direction is formed. ing. The shaft support 3
The shaft 50 is engaged with the shaft hole 48 so that the shaft 50 can rotate integrally, or the shaft 50 is engaged so that the shaft 50 can relatively rotate.

As shown in FIG. 4, the resin helical gear 31 of the present embodiment has the first and second webs 3.
Radial ribs 44, 45, formed on the surface side of
46 is formed to be inclined in the direction opposite to the rotation direction of the resin helical gear 31. As a result, when the resin helical gear 31 tries to be displaced in the rotation direction on the first rim 33 side with respect to the shaft support portion 36 side by the torque acting at the time of transmitting the rotating power, the radial rib 44 , 45, and 46 are compressed toward the shaft support portion 36, and a reaction force to prevent the deformation is applied from the radial ribs 44, 45, and 46 to the first rim 3.
3. Acts on the first circumferential rib 34 and the second circumferential rib 35. Thereby, the resin helical gear 31 of the present embodiment prevents a phase difference from occurring between the rotation on the inner peripheral side (the shaft support portion 36 side) and the rotation on the outer peripheral side (the first rim 33 side). The rotation transmission accuracy (dynamic accuracy) can be improved.

The resin helical gear 31 of the present embodiment is
As shown in FIG. 6, the second rim 41 and the shaft support 36
Is formed so as to be inclined in the rotation direction. As a result, in such a resin helical gear, the small-diameter helical gear 31b is meshed with another resin helical gear (not shown), and the small-diameter helical gear 31b is separated from the other resin helical gear by another resin helical gear. When transmitting rotation to the helical gear, torque acts on the second rim 41 in a direction opposite to the rotation direction, and the second rim 41 is applied to the shaft support 36 in a direction opposite to the rotation direction. Even when the second rim 41 is displaced (displaced), a reaction force acting on the second rim 41 from the radial rib 47 prevents the second rim 41 from being deformed in the circumferential direction. As a result, the resin helical gear 31 of the present embodiment is
A phase difference between the rotation of the rim 41 and the rotation of the shaft support portion 36 can be suppressed, and the rotation transmission accuracy (dynamic accuracy) can be improved.

The resin helical gear 31 of the present embodiment is
Are a first rim 33, a first circumferential rib 34, a second circumferential rib 35, a shaft support 36, a second rim 41, and a first rim 41.
The second ribs 37 and 38 are formed so that the thicknesses thereof are substantially the same or similar.
The first and second circumferential ribs 3 have thicknesses of 4, 45 and 46.
4 and 35 and the first and second webs 37 and 38 are formed thinner than the wall thickness. The thickness of the radial rib 47 is
The second rim 41 and the shaft support 36 are formed to be thinner than the wall thickness. Moreover, the radial rib 44 connected to the first rim 33 is formed to have a height H and a thickness (width W) smaller than those of the other radial ribs 45 and 46, and the first tooth portion. The rigidity of the first web 37 is reinforced without affecting the molding accuracy of the first web 37. Therefore, in the resin helical gear 31 of the present embodiment, the cooling rate after the injection molding is substantially the same in each part, the contraction deformation after the injection molding is uniform, and the molding is performed with high precision. Further, since the resin helical gear 31 of the present embodiment is sufficiently thinned as described above, the weight can be reduced, and the amount of shrinkage deformation after injection molding can be reduced. And the second tooth portion 42,
The entire shape including 43 can be formed with high precision.

As described above, the resin helical gear 31 of the present embodiment has excellent static accuracy (tooth profile accuracy) and dynamic accuracy (rotation transmission accuracy), similarly to the first embodiment. ), Smooth and high-precision rotation transmission is possible.

The resin helical gear 31 of the present embodiment is
In the above, the thickness of the first web 37, the second circumferential rib 35, and the second web 38 is made smaller than the thickness of the first rim 33 and the second rim 41, and the first web 37, Second
Of the circumferential rib 35 and the second web 38 of the first rim 3
If cooling is performed earlier than the third rim 41 and the second rim 41, even if the cooling of the first rim 33 and the second rim 41 is delayed, a large-diameter helical gear accompanying cooling after injection molding. The outer diameter of the helical gear 31b, which is smaller than that of the helical gear 31a, is reduced in the amount of diameter reduction deformation, so that it is possible to form the gear with higher precision.

Third Embodiment FIGS. 7 and 8 show a resin helical gear 51 according to a third embodiment of the present invention. 7 is a front view of the resin helical gear 51, and FIG. 8 is a cross-sectional view cut along the line CC of FIG.

The resin helical gear 51 shown in these figures
Is smaller in diameter than the resin helical gears 1 and 31 according to the first and second embodiments. As shown in FIG. 8, the resin helical gear 51 is formed in a symmetrical shape with respect to the center portion in the tooth width direction.
And a rim 54 formed with teeth 53 are connected by a thin plate-shaped web 55. An annular circumferential rib 56 is formed concentrically with the rim 54 inside the rim 54,
Radial ribs 57 are formed on both sides of the web 55 between the circumferential rib 56 and the shaft support 52. The radial rib 57 is formed so as to be inclined in a direction opposite to the rotational direction of the resin helical gear 51, and the upper end thereof is connected to the circumferential rib 56, and the lower end thereof is connected to the shaft support 57. It is connected. The teeth 53 and the rim 54 form a tooth portion 58.

Here, the rim 54, the circumferential rib 56 and the web 55 are formed with substantially the same thickness, and the radial rib 57
Is formed to be thinner than the thickness of the rim 54 and the like, so that the teeth 58 are formed with high precision.

The resin helical gear 51 having such a structure is used.
When the shaft hole 60 of the shaft support 52 is fitted to the shaft 59 so as to be integrally rotatable, and when the rotation is transmitted to the shaft 59, the rim 54 is rotated in the rotational direction with respect to the shaft support 52 by the torque applied from the outside. Although the ribs tend to move, the radial ribs 57 stretch and resist, so that the occurrence of a phase difference between the rotation of the rim 54 and the rotation of the shaft support 52 is suppressed. Therefore, the resin helical gear 51 of the present embodiment can transmit the rotation to the shaft 59 smoothly and with high precision.

Fourth Embodiment FIGS. 9 and 10 show a resin helical gear 61 according to a fourth embodiment of the present invention. 9 is a front view of the resin helical gear 61, and FIG. 10 is a cross-sectional view taken along a line DD of FIG. In addition, the resin helical gear 61 according to the present embodiment has a common configuration other than the resin helical gear 51 of the third embodiment except for the radial ribs 62, and thus has the same configuration. , The same components are denoted by the same reference numerals, and redundant description will be omitted.

That is, the resin helical gear 61 shown in FIGS. 9 and 10 is used for transmitting rotation in both the forward and reverse directions, and has a substantially V-shaped radial rib 62 in the circumferential direction. The web 55 is formed on the side surface of the web 55 between the rib 56 and the shaft support 52, and the ends of the substantially V-shaped radial ribs 62 are connected to the shaft support 55 and the circumferential rib 56, respectively.
Is improved in rigidity. That is, the radial rib 62
Is a first radial rib 62a formed to extend obliquely in a direction opposite to the normal rotation direction of the resin helical gear 61.
And a second radial rib 62b formed to extend obliquely in a direction opposite to the reverse rotation direction of the resin helical gear 61.

The resin helical gear 61 having the above-described structure is used.
Can smoothly and precisely transmit the rotation in both the forward and reverse directions to the shaft 59 fitted to the shaft hole 60 of the shaft support 52 so as to be integrally rotatable.

The resin helical gear 61 has a substantially V-shaped radial rib 62 as shown in FIGS.
If the arrangement is more dense than in the embodiment shown in FIG. 1 and the rigidity of the web 55 is further increased, the rotation can be transmitted more smoothly and with higher precision. (Image Forming Apparatus) [Fifth Embodiment] FIG. 13 shows a color copying machine (image forming apparatus) 70 in which the resin helical gears 1, 31, 51, 61 of the present invention are used. is there.

The image forming apparatus 70 shown in FIG.
And is sent between the photosensitive member 74 and the transfer roller 75 by
After transferring the color image formed on the photoreceptor 74 to the sheet material 72, the sheet material 72 is fed between the fixing rollers 77a and 77b of the fixing unit 76, and the color image formed on the surface of the sheet material 72 is fixed. The sheet material 72 after the completion of the fixing operation is discharged onto a discharge tray 80 by a pair of discharge rollers.

The photosensitive member 74 is adapted to be rotated clockwise in FIG. 13 (in the direction of the arrow), and has a cleaning unit 81, a neutralizing lamp 82, a charger 83,
An exposure unit 84 and a color developing unit 85 are arranged. As shown in FIG. 14, for example, the photoconductor 74 includes a photoconductor drive shaft 2 fixed to the center of rotation of a photoconductor drum 86 and a resin helical gear 1, 31, 31. A motor 87 as driving means connected to the shaft support portions 4, 36, 52 of the first and the second helical gears 1 (31, 51, 61) so as to be integrally rotatable. And the yellow (Y), magenta (M),
Four color images of cyan (C) and black (BK) are formed in an overlapping manner.

In the image forming apparatus 70 having such a configuration, the rotation of the motor 87 is controlled by the resin helical gear 1 (31, 51, 6).
1) is transmitted to the photoconductor 74 smoothly and with high precision, the fluctuation of the rotational angular velocity of the photoconductor 74 is suppressed, and the displacement of the color image of each color created on the photoconductor 74 is suppressed. A clear color image can be printed.

In the above embodiment, the photosensitive member 74
Although the photosensitive drum 86 is illustrated as an example, the present invention is not limited to this, and a photosensitive belt may be used as the photosensitive member 74. That is, as shown in FIG.
8, the resin helical gear 1 (31, 51, 61) according to each of the above embodiments is connected so as to be integrally rotatable, and this resin helical gear 1 (31, 51) is rotated. , 6
1) meshes with the gear (resin helical gear) 91 of the motor 87, and rotates the motor 87 through the gear 91 and the resin helical gear 1 (31, 51, 61) to form the driving roller 90.
To rotate the photosensitive belt 88 smoothly and with high precision. With such a configuration, the same effect as in the above embodiment can be obtained.

In the above embodiment, the resin helical gear 1 (3) for driving the photosensitive member 74 according to the above embodiments is used.
1, 51, 61), but the present invention is not limited to this, and the paper supply roller 71a of the paper supply unit 71, the registration roller 73a of the sheet conveyance unit 73, the color developing unit 8
5, developing rollers 85a to 85d, fixing rollers 77a, 7
7b and the like, and the resin helical gears 1 and 3 according to the above embodiments as a drive gear or an idle gear for transmitting rotation.
1, 51 and 61 can be used as appropriate. Further, the present invention is not limited to the above-described embodiment, and in the case of an image forming apparatus (not shown) having a configuration using an intermediate transfer member, the resin-made thin film according to each of the above-described embodiments is used for driving the intermediate transfer member. Gears 1, 3
1, 51, 61 can be used.

The resin helical gears 1, 31, 51, and 61 according to each of the above-described embodiments are, as described above,
Although the embodiment used for the image forming apparatus 70 such as a printer or a facsimile is illustrated, the invention is not limited to this, and can be widely applied to an ink jet printer, an automobile part, other precision machines, and the like. Will be possible.

In each of the above embodiments, the resin helical gears 1, 31, 51, 61 have been exemplified as the resin gears. However, the present invention is not limited to this, and spur gears, bevel gears, worm gears,
It can be widely applied to gears such as internal gears.

Further, the present invention is not limited to gears, but can be applied to a resin pulley as a rotation transmitting means having teeth meshing with a timing belt.

Further, the resin helical gears 1, 31, 51, and 61 according to the above embodiments are engaged with the shaft so as to be relatively rotatable, and the other resin helical gears are rotated by the other resin helical gears. Can be used to communicate.

[0058]

As described above, in the resin gear of the present invention, the radial rib is formed obliquely so as to receive a compressive force at the start of power transmission. Even if an attempt is made to displace in the rotational direction with respect to the support portion, a resistive force is generated in the radial rib to prevent the displacement, so that the tooth portion is displaced in a rotational direction with respect to the shaft support portion. Can be effectively suppressed, and variation in the rotational angular velocity between the tooth portion and the shaft support portion can be suppressed. Therefore, according to the resin gear of the present invention, smooth and high-precision rotation transmission is possible.

The resin gear of the present invention has a first radial rib formed so as to extend obliquely in a direction opposite to the rotation direction, and a slanted direction formed so as to extend obliquely in a direction opposite to the reverse rotation direction. Since the second radial rib is provided, the rotation in both the forward and reverse directions can be transmitted smoothly and with high precision.

Further, since the image forming apparatus of the present invention includes the resin gear according to the present invention which has excellent rotation transmission accuracy,
Since the rotation of the driving means is smoothly and accurately transmitted to the photoreceptor via the resin gear, fluctuations in the rotational angular velocity of the photoreceptor are suppressed, and color misregistration of each color image formed on the photoreceptor is performed. And a clear color image can be printed.

[Brief description of the drawings]

FIG. 1 is a front view of a resin gear according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the resin gear of FIG. 1 cut along line AA.

FIG. 3 is a rear view of the resin gear according to the first embodiment of the present invention.

FIG. 4 is a front view of a resin gear according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of the resin gear of FIG. 4 cut along line BB.

FIG. 6 is a rear view of a resin gear according to a second embodiment of the present invention.

FIG. 7 is a front view of a resin gear according to a third embodiment of the present invention.

FIG. 8 is a cross-sectional view of the resin gear of FIG. 7 cut along line CC.

FIG. 9 is a front view of a resin gear according to a fourth embodiment of the present invention.

FIG. 10 is a cross-sectional view of the resin gear of FIG. 9 cut along the line DD.

FIG. 11 is a view of a resin gear showing an application example of the fourth embodiment. FIG. 11 (a) is a front view of the resin gear, and FIG. 11 (b) is a partially enlarged view of FIG. 11 (a).

FIG. 12 is a cross-sectional view of the resin gear of FIG. 11A, taken along line EE.

FIG. 13 is a schematic configuration diagram of an image forming apparatus.

FIG. 14 is a diagram illustrating a drive mechanism of a photosensitive drum.

FIG. 15 is a diagram illustrating a drive mechanism of a photosensitive belt.

FIG. 16 is a front view of a conventional resin gear.

17 is a cross-sectional view of the resin gear of FIG. 16 cut along line FF.

FIG. 18 is a front view of a resin gear showing another conventional example.

FIG. 19 is a deformed state diagram showing a part of the resin gear shown in FIG. 17 in an enlarged manner.

[Explanation of symbols]

1, 31, 51, 61: resin helical gear (resin gear), 4, 36, 52: shaft support, 5, 37, 38,
55 ... web, 8, 42, 43, 58 ... tooth part, 1
0, 34 first circumferential rib, 11, 34 second circumferential rib, 12, 15, 45, 46, 57 radial rib, 56 circumferential rib, 62 radial Directional ribs, 62
a ... first radial rib, 62b ... second radial rib

Claims (7)

[Claims] 1. A substantially cylindrical tooth portion formed radially outward, a shaft support portion formed radially inward so as to be centered on the rotation center of the tooth portion, and a shaft support portion. And a thin plate-shaped web for connecting the teeth with the teeth. In the resin gear, a circumferential rib is formed on the web inside the teeth and at a position concentric with the teeth. A plurality of radial ribs connecting the direction rib and the shaft support portion along the side surface of the web are formed obliquely outward from the outer periphery of the shaft support portion so as to receive a compressive force at the start of power transmission. A resin gear, characterized in that: 2. A substantially cylindrical tooth formed radially outward, a shaft support formed radially inward so as to be centered on the rotation center of the tooth, and a shaft support. And a thin plate-shaped web for connecting the teeth with the teeth. In the resin gear, a circumferential rib is formed on the web inside the teeth and at a position concentric with the teeth. A first radial direction in which a plurality of radial ribs for connecting a direction rib and the shaft support portion along the side surface of the web are formed so as to extend obliquely from the outer periphery of the shaft support portion in a direction opposite to the normal rotation direction; A resin gear comprising: a rib; and a plurality of second radial ribs formed to extend obliquely from the outer periphery of the shaft support portion in a direction opposite to a reverse rotation direction. 3. A substantially cylindrical tooth portion formed radially outward, a shaft support portion formed radially inward so as to be centered on the rotation center of the tooth portion, and a shaft support portion. And a thin plate-shaped web connecting the tooth portion to the resin gear, wherein the web has a first circumferential rib formed inside the tooth portion and at a position concentric with the tooth portion. And the first
A second circumferential rib is formed inside and at a concentric position with respect to the circumferential rib, and a radial rib connecting the second circumferential rib and the first circumferential rib along a side surface of the web is formed. A plurality of resin gears are formed obliquely outward from the outer periphery of the second circumferential rib so as to receive a compressive force at the start of power transmission. 4. A substantially cylindrical tooth portion formed radially outward, a shaft support portion formed radially inward about the center of rotation of the tooth portion, and a shaft support portion. And a thin plate-shaped web connecting the tooth portion to the resin gear, wherein the web has a first circumferential rib formed inside the tooth portion and at a position concentric with the tooth portion. And the first
A second circumferential rib is formed inside and at a concentric position with respect to the circumferential rib, and a radial rib connecting the second circumferential rib and the first circumferential rib along a side surface of the web is formed. A plurality of first radial ribs extending obliquely from the outer periphery of the second circumferential rib in a direction opposite to the normal rotation direction;
A second radial rib formed so as to extend obliquely from the outer periphery of the circumferential rib in the reverse rotation direction to the reverse rotation direction. 5. A substantially cylindrical tooth portion formed radially outward, a shaft support portion formed radially inward so as to be centered on the rotation center of the tooth portion, and a shaft support portion. And a thin plate-shaped web that connects the tooth portion to the resin gear, wherein the web has a radial rib that connects the tooth portion and the shaft support portion along a side surface of the web, A plurality of resin gears are formed obliquely outward from the outer periphery of the shaft support portion so as to receive a compressive force at the start of power transmission. 6. An image forming apparatus comprising: the resin gear according to any one of claims 1 to 5; and a driving unit that rotationally drives a photoconductor via the resin gear. An image forming apparatus, wherein a rotation center of a resin gear and a rotation center of the rotating drum are coaxially located, and the resin gear and the rotating drum are connected so as to be able to rotate integrally. 7. A substantially cylindrical tooth formed radially outward, a shaft support formed radially inward so as to be centered on the rotation center of the tooth, and a shaft support. A resin-shaped rotation transmitting means, comprising: a thin plate-shaped web connecting the shaft and the tooth portion; and a radial rib radially formed on the web so as to extend from the shaft support portion toward the tooth portion. The resin-made rotation transmission means, wherein the radial rib is formed obliquely outward from the shaft support portion so as to receive a compressive force at the start of power transmission.