JP3002366B2 - Roller manufacturing method and roller molding die - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a roller used in an electrophotographic copying machine, a laser printer, a facsimile, and the like, and a roller molding die.

[0002]

2. Description of the Related Art Usually, as shown in FIG. 2, when manufacturing a roller R composed of a cylindrical main body 42 and shaft portions 44 provided at both ends of the main body 42, a semi-cylindrical mold is used. Hole 4
The upper mold 48 and the lower mold 50, on which the mold 6 is formed, face each other, a molten resin is injected into a cylindrical cavity, and after cooling, the mold is divided and the roller R is taken out.

However, the roller R thus formed has a parting line P (joining surface) between the upper die 48 and the lower die 50, that is, a parting line in the axial direction on the circumferential surface of the roller R. L occurs.

Further, the parting surfaces P of the upper mold 48 and the lower mold 50 are severely worn by the flow of the resin, and the molten resin flows into the worn parts, and burrs B are generated along the axial direction of the roller R. However, the diameter of the roller R may not be within the tolerance.

[0005] For this reason, deburring is provided at the mating surface of the upper die 48 and the lower die 50 so that no burr is generated, and the diameter of the main body 42 and the shaft portion 44 is designed to be within the tolerance. There is also a mold.

However, if the burrs are provided, the cross-sectional shapes of the main body 42 and the shaft portion 44 do not become a perfect circle, and the surface finish in the mold hole of the mold provided with the burrs is very difficult. The surface accuracy of the is deteriorated.

[0007]

SUMMARY OF THE INVENTION In view of the above facts, an object of the present invention is to provide a roller manufacturing method and a roller molding die which do not generate a parting line and burrs on the roller shaft. I do.

[0008]

According to a first aspect of the present invention, there is provided a method of manufacturing a roller including a columnar main body and shafts provided at both ends of the main body. Into the cavity obtained by face-to-face contact between two molds having a mold hole for molding the main body, and a core having a mold hole for molding one of the shaft portions whose end faces are closed. It is characterized by injecting molten resin and taking out the roller after cooling.

According to a second aspect of the present invention, there is provided a column-shaped main body,
A cavity formed by shaping a roller constituted by shafts provided at both ends of the main body and two molds each having a mold hole for forming the semi-columnar shaft and the main body. In a roller molding die in which a molten resin is injected into the mold and taken out after cooling, a core having an end face closed into a cavity obtained by face-to-face formation and a mold hole for molding one of the shaft portions is moved. It is characterized by being arranged as possible.

[0010]

According to the first aspect of the present invention, two molds each have a mold hole for forming a semi-columnar main body and a shaft portion, and the mold is opened in a direction orthogonal to the axial direction of the roller. .
Then, the molten resin is injected into the cavity by arranging the core having the closed end surface and the mold hole for molding one of the shaft portions into the cavity obtained by arranging the two molds. After cooling, take out the roller.

The core is moved in the demolding direction after the molten resin is cooled, so that the roller can be easily taken out. Further, no burr is formed on the shaft formed by the core along the axial direction of the surface.

According to the second aspect of the present invention, the core moves in the cavity obtained by the face-to-face matching. In this core, a mold hole for closing one end surface and forming one of the shaft portions is formed. For this reason, the shaft formed by the core does not generate burrs along the axial direction of its surface,
After the molten resin has cooled, the core moves in the demolding direction, thereby facilitating removal of the roller.

[0013]

EXAMPLE A description will be given of a roller molding die according to this example.

As shown in FIG. 1, a roller forming mold 60 is provided.
Has a fixed mold 62 and a movable mold 64. The fixed mold 62 and the movable mold 64 have one shaft 6
8 and a stepped semi-cylindrical mold hole 74 for molding the main body 70. Above the mold hole 74, a concave portion 76 reaching one end of the mold hole 74 for molding the main body 70 is formed in the parting surface P. The recess 76 forms an opening into which the core 72, which is a rectangular block, can be inserted when the fixed mold 62 and the movable mold 64 are surface-matched.
The core 72 has a cylindrical axial hole 78 whose end is closed along the moving direction (the direction of arrow A).
The other shaft portion 80 is formed.

Next, a method of manufacturing the roller 66 will be described.
The core 72 is inserted until the distal end surface contacts the bottom surface 76A of the concave portion 76, and the fixed mold 62 and the movable mold 64 are clamped. Thus, the cavity of one shaft portion 80 of the roller 66 is formed by the shaft hole 78 in the core 72, and the cavity of the other shaft portion 68 and the body 70 is formed by the mold hole 74.

Here, after the molten resin is injected into the cavity and cooled, the mold is opened and the roller 66 is taken out. At this time, the core 72 is moved away from the mold hole 74 so that the roller 66 is removed. Easy to take out.
In addition, since the burrs are not formed in the axial direction of the surface of the shaft 80 formed by the shaft die hole 78, a shaft with excellent surface accuracy can be manufactured.

As described above, the need to improve the surface accuracy of one shaft of the roller arises when a groove is formed in the other shaft. That is, since the shaft portion in which the groove is formed cannot be die-cut in the axial direction, the shaft portion is formed by dividing the mold. At this time, by improving the surface accuracy of one of the shaft portions, the sealing characteristics of the fitting portion can be improved.

The roller molding die 1 according to the present embodiment.
When the roller 16 manufactured by using the roller 16 is used as a magnet roller disposed in, for example, a copying machine or the like, the following functions are exhibited.

The shaft portion of the roller is supported by the bearing portion. However, in order to reduce the backlash of the roller, it is necessary to fit the shaft portion and form the shaft within the tolerance. However, since the shaft portion of the roller according to the present embodiment has a perfect circular shape, the above-mentioned tolerance can be easily cleared.

The magnet roller is placed in the copying machine in a state of being covered with the developing sleeve, but oil seals are applied to both ends of the magnet roller and the developing sleeve to prevent toner powder for development from entering the developing sleeve. Is done.
Since the magnet roller does not have a parting line and burrs on the peripheral surface, the main body and the shaft are perfectly circular,
The sealing effect is improved.

The shaft is also provided with an oil seal so that the toner powder does not leak out of the toner hopper.
Since this shaft is a perfect circle and has excellent surface accuracy, the toner hopper can be completely shut off from the outside.

[0022]

As described above, according to the present invention, a parting line and burrs along the axial direction are not generated on the shaft portion of the roller. Further, since the core moves in the removing direction, the roller can be easily taken out.

[Brief description of the drawings]

FIG. 1 is an exploded perspective view of a roller molding die according to the present embodiment.

FIG. 2 is an exploded perspective view of a conventional roller molding die.

[Explanation of symbols]

 62 Fixed mold 64 Moving mold 72 Core 76 Recess 78 Shaft type hole

Claims (2)

(57) [Claims] 1. A method for manufacturing a roller comprising a columnar main body and shafts provided at both ends of the main body, wherein a mold hole for molding the half-columnar shaft and the main body is formed. Inject the molten resin into the cavity obtained by lining up the two molds and the core in which the end face is closed and the mold hole for molding one of the shaft portions is formed, and take out the roller after cooling. Characteristic method of manufacturing rollers. 2. A roller composed of a columnar main body and shafts provided at both ends of the main body, and two rollers formed with a mold hole for forming the shaft and the main body having a semi-columnar shape. Inject molten resin into the cavity obtained by face-to-face molding,
In a roller molding die to be taken out after cooling, a core having an end face closed in a cavity obtained by face-to-face formation and a mold hole for molding one of the shaft portions is movably disposed. Roller molding die.