JP3621177B2 - Gear support mechanism - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an idler gear support mechanism that is disposed between a plurality of gears and controls the rotation direction and speed of the plurality of gears.
[0002]
[Prior art]
An idler gear, in which 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 as to mesh with the plurality of gears. These support mechanisms are generally well known. This support shaft was formed separately from the support plate.
[0003]
[Problems to be solved by the invention]
However, in the above-described idler gear support mechanism, the idler gear is directly supported by the support shaft, so that metal is used from the viewpoint of durability, which not only increases the weight and becomes expensive, but also supports the support plate and the support shaft. Since these are made of different materials, there is a problem that the recycling of the materials becomes troublesome. Further, since the support shaft is formed separately from the support plate, there is a problem that the number of parts increases. Further, since the support plate is formed by outsert molding, there is a problem that the mold becomes complicated.
[0004]
An object of the present invention is to provide a gear support mechanism that is lightweight, easy to recycle, and capable of reducing the number of parts.
[0005]
[Means for Solving the Problems]
The invention according to claim 1 is a support mechanism for an idler gear disposed between a plurality of gears, wherein the support pillar is integrally provided on a support plate on which the plurality of gears are supported, and the idler gear is rotated. It has a cylindrical portion which rotatably supports, and a bearing member having an arm engaging the leading end to the support plate, the support plate has a engaging piece having elasticity the arms are engaged, the post After the cylindrical portion of the bearing body is fitted, the arm is engaged with the tip of the engagement piece.
[0006]
According to a second aspect of the present invention, in the configuration of the first aspect, the bearing body is formed of a resin having high slidability and / or durability.
[0007]
The invention described in claim 3 employs a configuration in which a reinforcing member is inserted into the inside of the column in the configuration described in claim 1.
[0008]
According to a fourth aspect of the present invention, in the configuration according to the third aspect, the reinforcing member is a metal.
[0009]
【Example】
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 includes a photosensitive drum 4 and a developing device 6. Around the photosensitive drum 4, a charging charger 8, an eraser 10, a transfer device 12, and a cleaning device are provided. A blade 14 and a toner conveying coil 16 are provided.
[0010]
The developing device 6 is provided with a developing sleeve 18 for supplying toner to the photosensitive drum 4 and horizontally with the developing sleeve 18, and agitates, mixes and conveys the developer in the developing casing 24 in different directions 2. Two stirring screws 20 and 22, a hopper portion 26 formed integrally with the developing casing 24, and a toner bottle 28 attached to the hopper portion 26 and storing toner are provided.
[0011]
A magnetic permeability measuring sensor 34 for measuring the magnetic permeability of the developer is provided in the middle lower part of the stirring screw 22 near the hopper 26, and the toner concentration in the developing casing 24 is controlled based on this detection data. It has become.
[0012]
Next, an outline of the image forming process in the image forming apparatus 2 will be described.
First, the photosensitive drum 4 is neutralized by neutralizing light, and the surface potential is averaged to a reference potential of 0 to -150V. Next, it is charged by the charging charger 8 and the surface potential becomes around -900V. Next, exposure is performed at the exposure unit. Since the surface potential of the portion not irradiated with light (image portion) is maintained at −500 to −850 V, the toner on the developing sleeve 18 remains in the image portion even when a bias voltage of about −200 V is applied to the developing sleeve 18. Adhere to.
[0013]
The photosensitive drum 4 on which the toner image is formed rotates and moves, and a transfer sheet is fed from a sheet feeding unit (not shown) at a timing such that the leading end of the sheet and the leading end of the image coincide with each other at the transfer device 12. The toner image on the surface of the body drum 4 is transferred to the transfer paper. This 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.
[0014]
On the other hand, the residual toner remaining on the photosensitive drum 4 is scraped off by the cleaning blade 14. Thereafter, the charge remaining on the photosensitive drum 4 is removed by the charge-removing light, and an initial state without toner is obtained, and the process proceeds to the next image forming process again.
[0015]
The photosensitive drum 4, the charge eliminating device, the developing device 6, and the cleaning device described above are housed in an integral photosensitive member case (including the developing casing 24 as a part). In this case around the photosensitive member, the residual toner collected by the cleaning device is transported by the toner transport coil 16 and is sent to the stirring screw 22 near the hopper 26 through a transport path (not shown).
[0016]
Next, the developing device 6 will be described in detail.
The developing sleeve 18 has a fixed shaft in which a magnet is disposed, and the outer peripheral surface is covered with a non-magnetic pipe material. The developer moves on the developing sleeve 18 as the pipe material rotates. The developer is a two-component type composed of a small iron ball called a carrier and toner. The toner is charged by the circulating movement by the stirring screws 20 and 22 and adheres to the carrier and is carried to the surface of the photosensitive drum 4, so that it can adhere to the photosensitive drum 4 by the action of electrostatic force. Of the developer, the carrier circulates, but the toner is consumed because it adheres to the image portion of the photosensitive drum 4. Accordingly, replenishment is made as appropriate.
[0017]
The shafts 20a and 22a of the stirring screws 20 and 22 are rotatably supported by the side plates 36 of the image forming apparatus 2, and drive gears 30 and 32 are fixed to end portions of the shafts 20a and 22a, respectively. An idler gear 38 is disposed between the drive gears 30 and 32 so as to mesh with both gears. The idler gear 38 is supported by the bearing body 40 as shown in FIGS. The bearing body 40 includes a cylindrical portion 42 that rotatably supports the idler gear 38 and an arm 44 to which the cylindrical portion 42 is fixed. The bearing body 40 is formed of a resin having high slidability and durability, such as tetrafluoroethylene or polyacetal. One end of the arm 44 is provided with a protrusion 40 a that prevents the bearing body 40 from rotating as the idler gear 38 rotates. In this example, the cylindrical portion 42 and the arm 44 are configured separately, but may be configured integrally. In this case, the assembly man-hour can be reduced.
[0018]
On the other hand, the side plate 36 is provided with a column 46 that is provided integrally with the side plate 36 and into which the cylindrical portion 42 of the bearing body 40 is fitted. A hollow portion 46a is formed inside the column 46, and a metal reinforcing member 48 is inserted into the hollow portion 46a. The side plate 36 above the column 46 is provided with an engagement piece 50 having elasticity to engage with the protrusion 40a.
[0019]
As shown in FIG. 5, the bearing body 40 configured as described above has the cylindrical portion fitted to the column 46 while pushing the engaging piece 50 in the direction of the arrow with the protrusion 40 a, and the set shown in FIG. 4. Occupying the position, the idler gear 38 meshes with the drive gears 30 and 32. By applying this example to the agitation screws 20 and 22 of the image forming apparatus, the agitation of the toner becomes stable and a stable image free from jitter can be obtained.
[0020]
In this example, one idler gear 38 has been described. However, as shown in FIG. 6, a plurality of idler gears 38a, 38b are supported by the arm 44a as described above and meshed with the plurality of drive gears 52a, 52b, 52c. You may do it.
[0021]
【The invention's effect】
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 and the gear is supported, the number of parts can be reduced. Further, by forming the bearing body with a resin having high slidability and / or durability, the weight is reduced and recycling is facilitated. Since the reinforcing member is inserted into the support 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.
2 is a cross-sectional view taken along the line III-III in FIG.
FIG. 3 is a schematic cross-sectional view of an image forming apparatus to which the gear support mechanism of the present invention is applied.
4 is a cross-sectional view taken along the line IV-IV in FIG.
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 according to a modification 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 Tube portion 44 Arm 44a Arm 46 Strut 46a Hollow portion 48 Elastic member 50 Engagement piece 52a Drive gear 52b Drive gear 52c Drive gear

Claims (4)

An idler gear support mechanism disposed between a plurality of gears,
A bearing body having a column integrally provided on a support plate on which the plurality of gears are supported, a cylindrical portion that rotatably supports the idler gear, and an arm that engages a tip with the support plate. Have
The support plate has an engagement piece having elasticity with which the arm is engaged,
A gear support mechanism, wherein after the cylindrical portion of the bearing body is fitted to the support column, the arm is engaged with the tip of the engagement piece. 2. The gear support mechanism according to claim 1, wherein the bearing body is made of a resin having high slidability and / or durability. The gear support mechanism according to claim 1, wherein a reinforcing member is inserted into the support column. 4. The gear support mechanism according to claim 3, wherein the reinforcing member is made of metal.

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