JP4276738B2 - Drive unit gear retaining structure and image forming apparatus using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a gear retaining structure for a drive unit suitable for use in an image forming apparatus such as an electrophotographic copying machine, a printer, a facsimile, or a complex machine thereof.
[0002]
[Prior art]
In this type of conventional drive unit, a gear train composed of a plurality of gears rotatably mounted on a fixed shaft standing on a plate-like member (hereinafter referred to as a side plate) is provided, and an E-ring or the like is provided on the fixed shaft. Either a retaining ring was attached or another side plate was prepared, and the gear train was fixed between the two side plates. Examples of the latter include those disclosed in Japanese Patent Application Laid-Open No. 8-248717, which eliminates a retaining ring such as an E ring in order to improve recyclability (ease of disassembly), or a drive unit for cost reduction. One of the side plates forms the structure of the machine body and has a function of supporting one end of the fixed shaft.
[0003]
1 and 2 show a configuration similar to the drive unit disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 8-248717, and a plurality of fixed shafts 2... Are provided integrally with a housing 1 which is a resin side plate. Each of the fixed shafts 2 is mounted with a plurality of gears 3 constituting a gear train and attached to the machine body 4 in that state. On the machine body 4 side, a plurality of bosses 5... For immersing the tip of the fixed shaft 2 are provided.
[0004]
[Problems to be solved by the invention]
In such a drive unit, since the retaining ring such as the E-ring is eliminated as described above, when the fixed shaft 2 is leveled when the housing 1 to which the gear 3 is attached is assembled to the machine body 4, the gear 3 is The fixed shaft 2 may fall off. In order to prevent this, the assembling work must be performed while holding the gear 3 so that it does not fall off, so the workability is very poor.
[0005]
In particular, as shown in FIG. 3, in a drive unit in which a spring 6 is inserted between the housing 1 and the gear 3 in order to provide the torque limiter function of the paper discharge device (see, for example, Japanese Patent Laid-Open No. 7-315659), the gear It must be assembled while pressing 3 so that it does not jump out of the fixed shaft 2. In the case where the fixed shaft 2 and the housing 1 which is a side plate are integrally molded as shown in FIG. 3, it is possible to form a snap-fit groove on the fixed shaft 2 to prevent the gear from popping out. However, there is a problem that the mold structure is complicated and the cost is increased, and the processing accuracy of the fixed shaft portion is also adversely affected.
[0006]
Accordingly, an object of the present invention is to provide a drive unit gear retaining structure that eliminates these conventional problems and is inexpensive and excellent in recyclability.
[0007]
[Means for Solving the Problems]
In the drive unit gear retaining structure according to the first aspect of the present invention, in order to achieve the above object, a gear for transmitting a driving force to a fixed shaft standing on a plate-like member is rotatable. In the gear retaining structure of the drive unit for retaining the mounted gear from the fixed shaft , the gear has a flange on the outer periphery of the plate-like member in the axial direction of the fixed shaft , The plate-like member is provided with a lockable portion for locking the collar, and the collar is provided with a notch through which the lockable portion can pass, and the collar has a position other than the notch. In this embodiment, the gear is prevented from coming off from the fixed shaft by locking the lockable portion.
According to a second aspect of the present invention, there is provided a drive unit for rotatably mounting a gear for transmitting a driving force on a fixed shaft standing on a plate-like member and preventing the mounted gear from coming off from the fixed shaft . In the gear retaining structure, the gear has a collar on the outer periphery of the edge on the plate-shaped member side in the axial direction of the fixed shaft, and can be locked to lock the collar on the plate-shaped member. By providing a notch through which the lockable portion can pass and locking the lockable portion at a position other than the notch of the collar. and wherein to Rukoto the retaining from said fixed shaft.
Also pertaining to claim 3 is the gear retaining structure of the drive unit according to claim 1 or 2, the lockable portion includes a portion extending in the axial direction of the fixed shaft, at the site of the tip bending, characterized in that it consists of a part which can engaged with the collar.
Further, according to a fourth aspect of the present invention, in the drive unit gear retaining structure according to any one of the first to third aspects, a spring that pushes and urges the gear toward the distal end side of the fixed shaft is applied to the fixed shaft. It is characterized by being attached.
Further, according to a fifth aspect of the present invention, in the gear retaining structure of the drive unit according to the fourth aspect, the positions of the notch provided in the collar and the portion that can be locked to the collar of the lockable portion are provided. At the same time, the portion that can be locked to the collar is passed through the notch, the gear is rotated, and it can be prevented from coming off even when the gear is urged toward the distal end side of the fixed shaft by the urging force of the spring. The collar is locked at a portion that can be locked to the collar.
[0008]
According to a sixth aspect of the present invention, there is provided an image forming apparatus using the drive unit gear retaining structure according to any one of the first to fifth aspects .
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In the following description, common parts are denoted by common reference numerals.
[0010]
FIG. 4 is a cross-sectional view (A) and a plan view (B) showing an embodiment of a drive unit gear retaining structure according to the present invention. In FIG. 4, illustration of the machine body side is omitted. The housing 1 includes a vertical wall portion 10 that rises in a direction perpendicular to the fixed shaft 2 at the end portion on the side close to the fixed shaft 2 to which the spring 6 is attached among the plurality of fixed shafts 2. And a horizontal piece 11 that is bent horizontally inward. The horizontal piece portion 11 is a portion exhibiting a nail-like appearance. Note that the vertical wall portion 10 and the horizontal piece portion 11 may be either of an integral structure with the housing 1 or a separate structure. Further, in the present specification, vertical does not mean literally vertical, but in this embodiment, an oblique rising angle of the vertical wall portion 10 that is allowed to provide the horizontal piece portion 11 away from the surface of the housing 1. In addition, horizontal does not mean literally horizontal, but includes a range parallel to the surface of the housing 1 or a range that forms an appropriate angle with the horizontal.
[0011]
On the other hand, the gear 12 mounted on the fixed shaft 2 to which the spring 6 is attached includes a collar 13, and a notch 14 through which the horizontal piece 11 can pass is formed in the collar 13. Therefore, as can be seen from FIG. 4B, the gear 12 is mounted on the fixed shaft 2 so that the notch 14 of the collar 13 and the claw-shaped horizontal piece 11 are aligned, and then the gear 12 is rotated. The horizontal piece 11 presses the collar 13 of the gear 12 from above. In this way, even if the gear 12 is urged toward the distal end side of the fixed shaft 2 by the urging force of the spring 6, it can be prevented from coming off. The gear 12 and the collar 13 may be formed by integral molding of resin or the like.
[0012]
That is, since the gear 12 does not pop out even when urged by the spring 6, it can be assembled to the machine main body 4 side without holding the gear 12 by hand.
[0013]
【The invention's effect】
Since the gear retaining structure of the drive unit and the image forming apparatus using the same according to the present invention are as described above, the plate-like member is mounted after the gear is mounted on the fixed shaft standing on the plate-like member. Even if it is tilted, the gear does not come off the fixed shaft, and it can be easily attached to the machine or device, and the following operations can be performed easily. This has the effect of realizing a structure with excellent recyclability.
[0014]
The drive unit gear retaining structure and the image forming apparatus using the same according to the fifth aspect are as described above. Therefore, in order to provide a torque limiter function, the gear is detached from the fixed shaft with a spring. also it is energized, in addition to the effect of the upper Symbol Common uses a flange provided on the gear, attached to the fixed shaft pressing the each spring gear, and there is an effect that missing so that it is stopped .
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of a conventional gear mounting structure of a drive unit.
FIG. 2 is an exploded perspective view showing attachment to the machine body.
FIG. 3 is a schematic enlarged cross-sectional view of a main part in an attached state to the machine body of FIG.
4A and 4B are a cross-sectional view and a plan view showing an embodiment of a drive unit gear retaining structure according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Housing 2 Fixed shaft 3 Gear 4 Machine main body 5 Boss 6 Spring 10 Vertical wall part 11 of the housing 11 Horizontal piece part 12 Gear 13 Collar 14 Notch

Claims (6)

A gear for transmitting a driving force is rotatably mounted on a fixed shaft erected on a plate-like member,
In the drive unit gear retaining structure for retaining the mounted gear from the fixed shaft,
The gear has a flange on the outer periphery on the plate-like member side in the axial direction of the fixed shaft ,
The plate-like member is provided with a lockable portion for locking the collar,
The collar is provided with a notch through which the lockable portion can pass,
A gear retaining structure for a drive unit, wherein the gear is retained from the fixed shaft by retaining the anchorable portion at a position other than the notch of the collar. A gear for transmitting a driving force is rotatably mounted on a fixed shaft erected on a plate-like member,
In the drive unit gear retaining structure for retaining the mounted gear from the fixed shaft ,
The gear has a flange on the outer periphery of the edge on the plate-like member side in the axial direction of the fixed shaft,
The plate-like member is provided with a lockable portion for locking the collar ,
The collar is provided with a notch through which the lockable portion can pass,
By locking the lockable part at a position other than the notch of the collar,
Gear retaining structure of the drive unit, wherein to Rukoto the retaining from the fixed axis of the gear. In the drive unit gear retaining structure according to claim 1 or 2,
The lockable site, gear retaining structure of the drive unit, characterized in that it consists a part extending in the axial direction of the fixed shaft, a part which can engaged with the flange bend at the site of the tip. In the drive unit gear retaining structure according to any one of claims 1 to 3,
A drive unit gear retaining structure characterized in that a spring that pushes and urges the gear toward the distal end side of the fixed shaft is attached to the fixed shaft. In the drive unit gear retaining structure according to claim 4,
The position of the notch provided in the collar and the position of the lockable part that can be locked to the collar are aligned to pass the part that can be locked to the collar in the notch,
Rotate the gear,
The gear of the drive unit characterized in that the collar is locked at a portion that can be locked to the collar so that the gear can be prevented from coming off even if the gear is biased toward the distal end side of the fixed shaft by the biasing force of the spring. Retaining structure. 6. An image forming apparatus using the drive unit gear retaining structure according to claim 1.

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