JPH09196146A - Gear supporting mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear supporting mechanism which is light, easy in recycling, and capable of reducing the number of parts. SOLUTION: A supporting mechanism of a gear 38 to be arranged between a plurality of gears is provided with a column 46 integrated with a supporting plate 36 by which a plurality of gears are supported, and a bearing body 40 having a cylindrical part 42 to rotatably support the gear 38, and the cylindrical part 42 of the bearing body 40 is fitted to the column 46.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support mechanism for an idler gear which is arranged between a plurality of gears and controls the rotation direction and speed of the plurality of gears.

[0002]

2. Description of the Related Art A metal support shaft is fixed to a resin support plate on which a plurality of gears are supported, and an idler gear is rotatably supported directly on the support shaft so that the idler gear is engaged with the plurality of gears. The support mechanism of the idler gear adapted to match is generally well known. This support shaft was formed separately from the support plate.

[0003]

However, in the above idler gear support mechanism, the idler gear is supported directly on the support shaft, so that metal is used from the viewpoint of durability, and the weight increases and the cost increases. Not only that, but since the supporting plate and the support shaft are made of different materials, recycling of the material becomes troublesome. Further, since the support shaft is formed separately from the support plate, there is a problem that the number of parts increases. Moreover, since the support plate is formed by outsert molding, there is a problem that the mold becomes complicated.

The present invention is lightweight, easy to recycle,
It is an object of the present invention to provide a gear support mechanism capable of reducing the number of parts.

[0005]

According to the first aspect of the present invention,
A support mechanism for a gear arranged between a plurality of gears,
A support column integrally provided on a support plate on which the plurality of gears are supported, and a bearing body having a tubular portion that rotatably supports the idler gear are provided, and the tubular portion of the bearing body is provided on the support column. It is characterized by being fitted.

According to a second aspect of the present invention, in the structure according to the first aspect, the bearing body is formed of a resin having high slidability and / or durability.

According to a third aspect of the present invention, in the structure according to the first aspect, a reinforcing member is inserted inside the pillar.

According to a fourth aspect of the present invention, in the structure according to the third aspect, the reinforcing member is made of metal.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the gear support mechanism of the present invention is applied to a developing device of an image forming apparatus will be described below with reference to FIGS. As shown in FIG. 3, the image forming apparatus 2 is provided with a photosensitive drum 4 and a developing device 6, and a charger 8 and an eraser 1 are provided around the photosensitive drum 4.
0, a transfer device 12, a cleaning blade 14, and a toner carrying coil 16 are provided respectively.

The developing device 6 is provided with a developing sleeve 18 for supplying toner to the photosensitive drum 4, and the developing sleeve 18 and the developing sleeve 18 are arranged horizontally and agitate, mix, and mix the developer in the developing casing 24 in different directions. The two stirring screws 20 and 22 to be conveyed, the hopper portion 26 integrally formed with the developing casing 24, and the hopper portion 26 mounted on the hopper portion 26,
A toner bottle 28 for storing toner is provided.

A magnetic permeability measuring sensor 34 for measuring the magnetic permeability of the developer is provided in the lower part of the stirring screw 22 near the hopper portion 26, and the toner concentration in the developing casing 24 is controlled based on the detected data. It is supposed to do.

Next, the outline of the image forming process in the image forming apparatus 2 will be described. First, the photoconductor drum 4 is neutralized by the neutralization light, and the surface potential is averaged to the reference potential of 0 to -150V. Next, it is charged by the charger 8 and the surface potential becomes about -900V. Next, it is exposed in the exposure section. The surface potential of the part not irradiated with light (image part) is -5.
Since it is maintained at 00 to -850V, the developing sleeve 18
Even if a bias voltage of about -200V is applied to
The toner on the developing sleeve 18 adheres to the image portion.

The photoconductor drum 4 on which the toner image is formed is rotated and moved, and the transfer paper is sent from a paper feeding unit (not shown) at such a timing that the front end of the paper and the front end of the image coincide with each other in the transfer device 12, and the transfer device At 12, the toner image on the surface of the photosensitive drum 4 is transferred to the transfer paper. The transfer paper is sent to a fixing unit (not shown), and the toner is fused to the transfer paper by heat and pressure and discharged as a copy.

On the other hand, the residual toner remaining on the photosensitive drum 4 is scraped off by the cleaning blade 14. After that, the residual charges on the photosensitive drum 4 are eliminated by the elimination light, and the toner-free initial state is obtained, and the process proceeds to the next image forming step again.

The photoconductor drum 4, the charge removing device, the developing device 6, and the cleaning device described above are housed in an integral photoconductor case (including the developing casing 24 as a part). In the case around the photoconductor, the residual toner collected by the cleaning device is carried by the toner carrying coil 16 and sent to the stirring screw 22 near the hopper section 26 through a carrying path (not shown).

Next, the developing device 6 will be described in detail. The developing sleeve 18 has a fixed shaft inside which a magnet is arranged, and its outer peripheral surface is covered with a non-magnetic pipe material. When the pipe material rotates, the developer moves on the developing sleeve 18. The developer is a two-component type composed of small iron balls called carrier and toner. The toner is charged by the circulation movement of the stirring screws 20 and 22, and is attached to the carrier to be carried to the surface of the photoconductor drum 4, and can be attached to the photoconductor drum 4 by the action of electrostatic force. Of the developer, the carrier circulates, but the toner adheres to the image portion of the photosensitive drum 4 and is consumed. Therefore, the supply is appropriately performed.

Shafts 20a, 2 of the stirring screws 20, 22
Each of the shafts 2a is rotatably supported by a side plate 36 of the image forming apparatus 2, and drive gears 30 and 32 are fixed to the ends of the shafts 20a and 22a, respectively. Drive gear 3
An idler gear 38 is arranged between 0 and 32 so as to mesh with both gears. The idler gear 38 is shown in FIG.
As shown in FIG. 2, it is supported by the bearing body 40. The bearing body 40 has a tubular portion 42 that rotatably supports the idler gear 38, and an arm 44 to which the tubular portion 42 is fixed. The bearing body 40 is made of a resin having high slidability and durability, for example,
It is made of tetrafluoroethylene, polyacetal, or the like. At one end of the arm 44, a protrusion 40a that prevents the bearing body 40 from rotating as the idler gear 38 rotates.
Is provided. In this example, the cylindrical portion 42 and the arm 44 are formed separately, but they may be formed integrally. In this case, the number of assembling steps can be reduced.

On the other hand, the side plate 36 is provided integrally with the side plate 36, and the support column 46 into which the cylindrical portion 42 of the bearing body 40 is fitted.
Is provided. A hollow portion 46a is formed inside the column 46, and a metallic reinforcing member 48 is inserted into the hollow portion 46a. Side plate 36 above the post 46
Is provided with an elastic engaging piece 50 that engages with the protrusion 40a.

The bearing body 40 constructed as described above is shown in FIG.
As shown in FIG. 4, the protrusion 40a pushes up the engaging piece 50 in the direction of the arrow while the tubular portion is fitted to the support column 46, and the idler gear 38 occupies the set position shown in FIG. Mesh with. By applying this example to the stirring screws 20 and 22 of the image forming apparatus, the stirring of the toner is stabilized, and a stable image without jitter can be obtained.

Although one idler gear 38 has been described in this embodiment, as shown in FIG. 6, the plurality of idler gears 38a and 38b are supported by the arm 44a as described above, and the plurality of drive gears 52a, 52b and 52c are supported. You may make it mesh with.

[0021]

According to the present invention, since the cylindrical portion of the bearing body is fitted to the support column integrally provided on the support plate to support the gear, the number of parts can be reduced. Further, by forming the bearing body with a resin having high slidability and / or durability, the weight becomes light and the recycling becomes easy. Since the reinforcing member is inserted inside the column, the strength is increased.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a gear support mechanism according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line III-III in FIG.

FIG. 3 is a schematic sectional view of an image forming apparatus to which a gear support mechanism of the present invention is applied.

FIG. 4 is a sectional view taken along line IV-IV of FIG. 1;

FIG. 5 is a cross-sectional view illustrating mounting of a bearing body.

FIG. 6 is a schematic sectional view showing a gear support mechanism of a modified example of the present invention.

[Explanation of symbols]

 30 drive gear 32 drive gear 36 side plate 38 idler gear 38a idler gear 38b idler gear 40 bearing body 40a protrusion 42 cylinder part 44 arm 44a arm 46 strut 46a hollow part 48 elastic member 50 engaging piece 52a drive gear 52b drive gear 52c drive gear

Claims (4)

[Claims] 1. A support mechanism for a gear arranged between a plurality of gears, wherein a pillar integrally provided on a support plate on which the plurality of gears are supported and the idler gear are rotatably supported. And a bearing body having a tubular portion, and the tubular portion of the bearing body is fitted to the support column. 2. The gear support mechanism according to claim 1, wherein the bearing body is made of a resin having high slidability and / or durability. 3. The gear supporting mechanism according to claim 1, wherein a reinforcing member is inserted inside the support column. 4. The gear supporting mechanism according to claim 3, wherein the reinforcing member is made of metal.