JP7089738B2 - Bearing member - Google Patents

Description

In the present invention, for example, the screw used for stirring and transporting a developer containing toner contained in a housing can be rotated while the toner is prevented from leaking through its rotation shaft. The present invention relates to a bearing member of an electrophotographic apparatus supported by a housing.

In an electrophotographic apparatus such as an electrophotographic copying machine or a printer, a screw is provided in the housing of the toner cartridge in order to stir or convey the developer containing the toner inside (for example, Patent Document 1). reference) .
As shown in FIG. 16, the screw 200 is provided with, for example, a screw portion 211 spirally formed on the rotary shaft 210 so as to project in the circumferential direction of the rotary shaft 210, and both ends of the rotary shaft 210 are provided. It is rotatably supported by the housing 110 via the bearing member 300.

The bearing member 300 includes a member main body 310 made of a thermoplastic resin such as polypropylene, and a seal 320 made of a thermoplastic resin elastomer integrally provided with the member main body 310.
The screw 200 is supported by the shaft hole 311 in the member main body 310 in a state where the end of the rotary shaft 210 is rotatably sealed via the seal main body 321 of the seal 320.
Further, the member main body portion 310 is usually provided with a meat stealing recess 312 on the surface facing the outside of the housing 110 on the opposite side of the seal portion 320, as shown in FIG. 16, in order to prevent sink marks and the like.

Japanese Unexamined Patent Publication No. 8-190268

By the way, in recent years, due to the need for energy-saving driving, toner is being fixed at a low temperature, so it is necessary to dissipate heat so that the frictional heat generated between the screw and the bearing member does not affect the toner as much as possible. ing.

On the other hand, in the conventional electrophotographic apparatus, a large number of cooling means such as a fan are provided, but these are obstacles to the miniaturization and cost reduction of the electrophotographic apparatus.

In view of the above circumstances, it is an object of the present invention to provide a bearing member that easily dissipates frictional heat generated by friction with a rotating shaft of a screw to the outside of a housing.

The inventor of the present invention has repeated research in order to achieve the above object, and due to the presence of the meat stealing recess 312, the heat capacity of the portion that transfers the frictional heat generated in the seal portion of the bearing member to the peripheral wall side of the housing is increased. Since it is small, it is difficult for frictional heat to escape to the outside of the housing, and it is found that heat is trapped inside the housing, causing deterioration of the toner. As a result of diligent studies, the present invention has been completed.

That is, the bearing member according to the present invention (hereinafter referred to as "the bearing member of the present invention") is provided in the housing so as to rotatably receive the rotating shaft of the screw that stirs or conveys the toner in a sealed state. It is provided with a member main body made of a thermoplastic resin composition and a sealing part made of a thermoplastic resin elastomer, and the member main body has an opening on one side and the rotation on a bottom provided on the other side. A cylindrical portion having a through hole for a shaft is provided, the tubular portion has a recess for stealing meat at a position facing the opening at the bottom, and the sealing portion has a tubular portion inscribed in the tubular portion. The base cylinder is integrated with the base cylinder in a state of communicating with the through hole inside the base cylinder, and is concentric with the through hole from the bottom side of the cylinder toward the opening side. It has a seal body portion that is gradually reduced in diameter so that the rotating shaft can be rotatably fitted, and a part of the thermoplastic resin elastomer constituting the sealing portion is tightly fitted in the meat stealing recess. Along the outer wall surface of the bearing member of the electrophotographic apparatus, the sealing portion is parallel to the central axis of the base cylinder portion, and the cross-sectional shape increases toward the outside in the radial direction of the sealing portion. The member main body is provided with a rib fitting groove in which the rib extending from the opening end of the cylindrical portion toward the bottom is fitted to the inner wall of the tubular portion . ..

In the bearing member of the present invention, the recess for stealing meat is provided so as not to impair the molding accuracy of the member body due to sink marks during molding of the member body, and if the molding accuracy can be ensured, the depth and size thereof are particularly high. Not limited. Further, in consideration of heat dissipation, it is preferable that a plurality of places are uniformly provided around the through hole.
The thermoplastic resin composition constituting the main body of the member is not particularly limited, and for example, the main component is a styrene resin such as a polypropylene resin, an AS resin, or an ABS resin, a modified polyphenylene oxide resin, a polyamide resin, a polycarbonate resin, or a polyphenylene. Examples thereof include thermoplastic resins such as ether resins, polyphenylene sulfide resins, and polyester resins such as polyethylene terephthalate, which may be used alone or in combination.
Further, the above-mentioned thermoplastic resin composition may be blended with a filler for imparting thermal conductivity having high thermal conductivity for the purpose of imparting thermal conductivity, if necessary, or the heat of an injection-molded product has been conventionally used. A known additive added to the plastic resin composition may be added.
The filler for imparting thermal conductivity is not particularly limited, but is limited to metal oxides such as aluminum oxide, boron nitride, aluminum nitride, silicon nitride, magnesium oxide, zinc oxide, silicon carbide, quartz and aluminum hydroxide, and metal nitrides. , Metal carbide, metal hydroxide, graphite and the like, and graphite is preferable.
The thermoplastic resin elastomer constituting the seal portion is not particularly limited, and examples thereof include thermoplastic elastomers such as polyester-based elastomers, polyamide-based elastomers, and acrylic-based elastomers, and if necessary, thermal conductivity. A filler for imparting thermal conductivity having high thermal conductivity may be blended for the purpose of imparting.

The bearing member of the present invention is not particularly limited, but the member main body portion has a retaining hole that penetrates inside and outside the tubular portion in the vicinity of the bottom of the tubular portion, and the sealing portion is the outer periphery of the base tubular portion. A structure may be provided in which a retaining protrusion that protrudes from the surface and fits into the retaining hole is provided.
That is, by adopting such a structure, it is possible to prevent the seal portion from coming off from the tubular portion and to prevent the seal portion from rotating together with the rotation of the rotating shaft of the screw.

The bearing member of the present invention is not particularly limited, but the flange portion is provided on the bottom side of the retaining hole and is externally fitted to the member main body portion along the flange portion to prevent the retaining protrusion. A structure may be configured in which an annular packing portion integrally formed with the seal portion is provided via the portion.
That is, since the annular packing is fitted to the housing, the bearing member can be reliably set at a predetermined position of the housing regardless of the molding accuracy of the housing.

The bearing member of the present invention is not particularly limited, but the member main body portion has a substantially fan-shaped or irregular notch portion communicating with the inside of the tubular portion on the opening side of the tubular portion, and the sealing portion. However, there may be a configuration in which the fitting portion that protrudes outward from the opening side end portion of the seal portion main body portion and fits into the notch portion is integrally molded with the seal portion main body portion.
That is, with such a structure, it is possible to hold the seal portion main body portion and the tubular portion so as not to form a gap.

The material of the screw pivotally supported by the bearing member of the present invention is not particularly limited, but is preferably formed of a thermoplastic resin composition or a metal material having high thermal conductivity.

The bearing member of the present invention is not particularly limited, but can be manufactured by, for example, two-color molding in which the main body of the member is injection-molded and then the seal portion is injection-molded.

As described above, the bearing member according to the present invention is provided in the housing so as to rotatably receive the rotating shaft of the screw that agitates or conveys the toner in a sealed state, and is made of a thermoplastic resin composition. A cylindrical portion having a main body and a sealing portion made of a thermoplastic resin elastomer, the member main body having an opening on one side and a through hole for the rotating shaft on the bottom provided on the other side. The cylindrical portion has a recess for stealing meat at a position facing the opening at the bottom, and the sealing portion has a tubular base cylinder portion inscribed in the tubular portion and a base cylinder thereof. Inside the portion, it is integrated with the base cylinder portion in a state of communicating with the through hole, and the diameter is gradually reduced concentrically with the through hole from the bottom side of the tubular portion toward the opening side, and the rotation shaft. Is a bearing member of an electrophotographic apparatus that has a seal body portion that is rotatably fitted and a part of the thermoplastic resin elastomer constituting the seal portion is tightly fitted in the meat stealing recess. The seal portion is provided with a plurality of ribs that are parallel to the central axis of the base cylinder portion and whose cross-sectional shape increases toward the outside in the radial direction of the seal portion intermittently along the outer wall surface. However, the inner wall of the cylindrical portion is provided with a rib fitting groove into which the rib extending in the bottom direction from the opening end of the tubular portion is fitted .

That is, since the member main body portion is provided with the meat stealing recess, it is possible to prevent sink marks and the like during molding of the member main body portion, and the molding accuracy of the member main body portion is good.
Further, since a part of the thermoplastic resin elastomer constituting the seal portion is tightly fitted in the meat stealing recess, the member body is provided with the meat stealing recess on the opposite side to the seal portion. In comparison, the heat capacity of the bearing member is large.

Therefore, heat can easily escape to the outside of the housing as compared with the one provided with a recess for stealing meat on the opposite side of the seal portion of the member main body, and the toner is stored in the housing due to the friction between the rotating shaft of the screw and the bearing portion. Deterioration can be suppressed.
Moreover, it can be easily obtained by two-color molding in which the member main body portion is injection-molded and then the seal portion is injection-molded, and the productivity is good.
In addition, the ribs can reinforce the base cylinder and prevent the base cylinder from rotating.

It is a perspective view which shows the 1st Embodiment of the bearing member of this invention. It is a front view of the bearing member of FIG. It is a back surface of the bearing member of FIG. It is a plane surface of the bearing member of FIG. It is a right side view of the bearing member of FIG. FIG. 2 is a cross-sectional view taken along the line AA of FIG. FIG. 2 is a cross-sectional view taken along the line BB of FIG. FIG. 2 is a sectional view taken along the line CC of FIG. It is a front view of the member main body part of the bearing member of FIG. 9 is a cross-sectional view taken along the line DD of the member main body of FIG. It is sectional drawing which shows the state which the bearing member of FIG. 1 is set in a housing in the bearing state of a screw. It is a front view which shows the 2nd Embodiment of the bearing member of this invention. FIG. 12 is a cross-sectional view taken along the line EE of FIG. It is a figure which shows roughly the apparatus used for the verification experiment. It is a graph showing the result of the verification experiment. It is sectional drawing which shows the state which the conventional bearing member was set in the housing in the bearing state of a screw.

1 to 8 show the first embodiment of the bearing member of the present invention.
As shown in FIGS. 1 to 8, the bearing member 1a includes a member main body portion 2 and a seal portion 3a.

The member main body 2 is made of a polypropylene resin composition and includes a tubular portion 21 and a flange portion 22.
The tubular portion 21 has a bottomed tubular shape having an opening on one side, and as shown in FIGS. 9 and 10, the rotary shaft of the screw to be pivotally supported is a shaft hole into which the rotary shaft is rotatably fitted. A through hole 21a is bored in the center of the bottom 21b, and four arc-shaped recesses for stealing meat 21c are recessed so as to surround the through hole 21a.

Further, as shown in FIG. 9, the tubular portion 21 is provided with two stepped-down portions 21d, which are gate positions, symmetrically on the end surface on the opening side thereof with the central axis of the tubular portion 21 interposed therebetween. Three rib fitting grooves 21e having a substantially trapezoidal cross section are intermittently recessed on the inner wall surface extending from the end surface on the opening side to substantially the vicinity of the bottom between the drop portion 21d and the step drop portion 21d. ..
The flange portion 22 extends to the outside of the tubular portion 21 on the bottom 21b side of the tubular portion 21.
The tubular portion 21 is provided with four retaining holes 21f that penetrate the tubular portion 21 intermittently in the circumferential direction of the tubular portion 21 so as to be along the end surface of the flange portion 22 on the opening side of the tubular portion. ..

The seal portion 3a is made of a polyester resin-based elastomer, and includes a base cylinder portion 31, a seal portion main body 32, six ribs 33, two gate trace covering portions 34, and four fitting leg portions 35. It is provided with four retaining protrusions 36.
The outer peripheral surface of the base tubular portion 31 has a cylindrical shape along the inner peripheral surface of the tubular portion 21, one end surface thereof abuts on the bottom 21b of the tubular portion 21, and the other end surface thereof is the tubular portion 21. It almost coincides with the open end of.

The seal portion main body 32 is provided concentrically with the through hole 21a, and has a lip shape in which the diameter is gradually reduced from the bottom 21b side of the tubular portion 21 toward the opening side.
The six ribs 33 project from the outer wall surface of the base cylinder portion 31 and are closely fitted into the rib fitting grooves 21e.

The two gate trace covering portions 34 are projected from the outer wall surface of the base cylinder portion 31 and are fitted into the stepped-down portion 21d to cover the gate trace 21g shown in FIG. 7.
Each of the four fitting legs 35 is tightly fitted into the meat stealing recess 21c.

The four retaining protrusions 36 project from the outer wall surface of the base cylinder portion 31 and are closely fitted to the retaining holes 21f, respectively, and the tip surface substantially coincides with the outer wall surface of the tubular portion 21. There is.

Then, as shown in FIG. 9, this bearing member 1a is set in the housing 41 of the toner cartridge 4, and can pivotally support the rotating shaft 51 of the stirring screw 5a and the supply screw 5b.

Since the bearing member 1a is configured as described above, it has the following excellent effects.
(1) Since the fitting leg portion 35 constituting a part of the seal portion 3a is tightly fitted to the meat stealing recess 21c, the heat capacity of the outer wall side portion of the housing 41 of the bearing member 1a is the conventional bearing member. It will be larger than 300.
That is, the frictional heat generated by the rotating shaft 51 and the bearing member 1a can be easily dissipated to the outside of the housing 41 via the housing 41.
Therefore, it is possible to prevent the toner in the housing 41 from being altered without using a cooling device such as a fan.
(2) Since the member main body 2 is provided with the meat stealing recess 21c, the member main body 2 can be molded with high accuracy.
(3) Since the seal portion 3a is provided with the rib 33 and the rib 33 is in a state of being tightly fitted in the fitting concave groove, it is possible to prevent the seal portion 3a from rotating together and the rib 33. The seal portion main body 32 is firmly supported by the tubular portion 21 of the member main body portion 2 in a close contact state.
(4) Since a step-down portion 21d in which a gate is provided is provided on the opening end side of the cylindrical portion 21 of the member main body portion 2, the gate mark 21g of the step-down portion 21d is covered with the gate mark covering portion 34. The gate mark 21g is not visible from the outside, and the appearance is good, and the sealing portion 3a can be prevented from rotating together.
(5) The seal portion 3a is provided with a retaining protrusion 36, and the retaining protrusion 36 is in a state of being tightly fitted into the retaining hole 21f provided in the tubular portion 21 of the member main body portion 2. Therefore, it is possible to prevent the sealing portion 3a from rotating together.

12 and 13 show a second embodiment of the bearing member of the present invention.
As shown in FIGS. 12 and 13, the bearing member 1b includes the packing portion 37 in a state where the seal portion 3b is externally fitted to the tubular portion 21 along the flange portion 22. It is the same as the member 1a.

As shown in FIG. 13, the packing portion 37 is integrally molded with the retaining protrusion 36.
In FIGS. 12 and 13, the same components as the bearing member 1a are designated by the same reference numerals as those of the bearing member 1a.

Since the bearing member 1b includes the packing portion 37 as described above, the bearing member 1b has the same effect as the bearing member 1a of the first embodiment, and also has the same effect as the bearing member 1b of the housing 41. Even if the molding accuracy of the bearing is a little poor, it has the effect that it can be mounted on the housing 41 so that the toner does not leak out.

(Verification experiment)
A sample A made of acetal resin having an outer diameter of 16 mm, a thickness of 3 mm, and an inner diameter of a shaft hole of 6 mm as a bearing member sample, and a recess for meat stealing having a depth of 2 mm and a cross-sectional area of 8.5 mm ² on one surface in the thickness direction are used as shafts. Sample B having the same dimensions as sample A was prepared except that nine were provided around the holes.
Then, as shown in FIG. 14, the samples A and B are set in a bearing state on the sample S in which the shaft 62 made of polypropylene resin connected to the motor 61 is supported by the support portion 63, and then the sample is set on the shaft 62. While applying a load of 0.05 mm upward at the portion S, the shaft 62 was rotated at 500 rpm, and the temperature rise of the shaft 62 exposed from the sample S was measured with a thermograph, and the results are shown in FIG. ..

The sample B was set with the opening side of the meat stealing recess facing the open end side of the shaft 62.
Further, in FIG. 14, 64 is a bearing.
In FIG. 15, ◯ indicates the temperature on the motor 61 side of the sample A, ● indicates the temperature on the shaft open end side of the sample A, Δ indicates the temperature on the motor 61 side of the sample B, and ▲ represents the temperature on the shaft open end side of the sample A.

From FIG. 13, it can be seen that the temperature rise of the sample A having no recess for stealing meat is smaller than that of the sample B before and after the sample S.
That is, it is considered that the solid sample A has a larger heat capacity and can prevent the temperature from rising.

1a, 1b Bearing member 2 Member body 21 Cylindrical portion 22 Flange portion 21a Through hole (shaft hole)
21b Bottom 21c Meat stealing recess 21d Step-down part 21e Rib fitting groove 21f Retaining hole 21g Gate mark 3a, 3b Sealing part 31 Base cylinder 32 Sealing part main body 33 Rib 34 Gate mark covering part 35 Fitting leg part 36 Retaining Protrusion 37 Circular packing 4 Toner cartridge 41 Housing 5a Stirring screw 5b Supply screw 51 Rotating shaft

Claims (5)

It is provided in the housing so that the rotating shaft of the screw that agitates or conveys the toner is rotatably received in the sealed state.
A member main body made of a thermoplastic resin composition and a sealing part made of a thermoplastic resin elastomer are provided.
The member main body portion has a cylindrical portion having an opening on one side and a through hole for the rotating shaft on the bottom provided on the other side.
The tubular portion has a meat stealing recess at a position facing the opening at the bottom.
The seal portion is integrated into the base cylinder portion having a cylindrical shape inscribed in the tubular portion and the base cylinder portion in a state of communicating with the through hole inside the base cylinder portion, and the bottom of the tubular portion. A thermoplastic resin elastomer having a seal main body portion whose diameter is gradually reduced concentrically with the through hole from the side toward the opening side and in which the rotating shaft is rotatably fitted, and which constitutes the sealing portion. A part of the bearing member of the electrophotographic apparatus that is tightly fitted in the meat stealing recess.
The seal portion is parallel to the central axis of the base cylinder portion, and is provided with a plurality of ribs whose cross-sectional shape increases toward the radial outer side of the seal portion intermittently along the outer wall surface.
A bearing member , wherein the member main body portion is provided with a rib fitting groove into which the rib extending from the opening end of the tubular portion toward the bottom is fitted on the inner wall of the tubular portion . The bearing member according to claim 1 , wherein the member main body portion has a flange portion extending in the outer peripheral direction on the bottom side . The member main body portion has a retaining hole that penetrates inside and outside the tubular portion in the vicinity of the bottom of the tubular portion.
The bearing member according to claim 1 or 2, wherein the seal portion protrudes from the outer peripheral surface of the base cylinder portion and includes a retaining protrusion that fits into the retaining hole . The member main body portion has a flange portion extending in the outer peripheral direction on the bottom side thereof.
The flange portion is provided on the bottom side of the retaining hole, and the flange portion is provided on the bottom side thereof.
The bearing member according to claim 3, further comprising an annular packing portion that is externally fitted to the member main body portion along the flange portion and integrally formed with the seal portion via the retaining protrusion. The method for manufacturing a bearing member according to any one of claims 1 to 4, wherein the main body of the member is injection-molded and then the seal portion is injection-molded.

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