JP2001180860A - Paper feed switching gate and manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the rigidity of a shaft part of a gate used to switch a paper feed in a business machine such as a copier. SOLUTION: When integrally molding a shaft part 2 and a claw part 3 using a thermoplastic resin, for example, by injection molding, a cross-sectional shape of the shaft part 2 is formed in a polygonal shape to improve rigidity.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a gate used for switching paper passing in a copying machine, a facsimile, a printer or the like.

[0002]

2. Description of the Related Art A gate of this type comprises a shaft portion and a claw portion extending from the shaft portion. Conventionally, a shaft portion made of metal is inserted into an injection mold and the claw portion is formed. It is manufactured by a method of molding with a thermoplastic resin. Since this method requires two steps of a step of inserting the shaft and a step of injection-molding the claw and is inferior in productivity, it has been proposed that the shaft is also integrally formed with the claw by resin. ing. In this case, a hollow portion is provided in the shaft portion by applying a gas injection molding method in order to prevent the warpage of the shaft portion (Japanese Patent Laid-Open No. 9-175708).

[0003]

In the above-mentioned conventional paper passage switching gate, even if a hollow portion is provided in the shaft portion, the rigidity is still insufficient, and it is easy to bend when switching the paper passage, which may cause malfunction. Was.

[0004]

According to the present invention, as a means for solving the above-mentioned conventional problems, a shaft portion (2) and a claw portion (3) are integrally formed of a thermoplastic resin. (2) provides a paper passage switching gate (1) having a polygonal cross section. The shaft (2) preferably has a triangular cross section, and the shaft (2) has a claw (3) at the vertex of the triangular cross section.
It is desirable that they are arranged in the sending direction. Further, when a fibrous filler is mixed in the thermoplastic resin, the rigidity is improved and the resin is hardly bent.

According to the present invention, a claw (3) is injected into the shaping portion of the cavity of the cavity of the injection mold from the side opposite to the side from which the resin is injected.
(3) There is provided a method for manufacturing a paper feed switching gate (1) for injecting gas from the side opposite to the sending side.

[0006]

In the present invention, the shaft and the claw are integrally formed of a thermoplastic resin, so that the manufacturing process is one step. In addition, since the shaft portion has a polygonal cross section, the rigidity of the shaft portion is improved by the rib effect of the corner portion of the shape.

If the shaft (2) is triangular in cross section, at least two corners become acute and the rib effect becomes large, and the number of corners is minimized. When the tabs are arranged in the direction in which the pawls (3) are inserted, that is, in the direction in which the paper is introduced, there is almost no interference of the corners with the sliding of the paper.

Further, when the hollow portion (4) is formed inside the shaft portion (2), the rigidity of the shaft portion (2) is further improved. The shaft portion (2) having the hollow portion (4) is manufactured by a gas injection molding method. In this case, gas pressure is applied to the hollow portion (4) to cause sinkage and warpage of the molded product. Is prevented. Even if a fibrous filler is mixed with the thermoplastic resin as the material of the gate (1), the rigidity of the shaft (2) is further improved.

When the gate (1) of the present invention is manufactured by an injection molding method or a gas injection molding method, a claw (3) is inserted into the shaft molding portion of the cavity of the injection molding die, that is, the paper is introduced. When the resin melt is introduced from the opposite side or gas is injected, the sliding of the paper is not interfered by the injection gate trace and the gas pressure entrance trace of the molded product.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described with reference to an embodiment shown in FIGS. 1 to 3. A paper feed switching gate (1) has a shaft portion (2A, 2A) having small-diameter shaft ends (2A, 2A) provided at both ends. The shaft portion (2) has a triangular cross section, and the apex of the triangular shape is arranged with the claw portion (3) inserted in the inserting direction. A pair of left and right hollow portions (4, 4) are formed in the shaft portion (2). The shaft portion (2) and the claw portion (3) are integrally manufactured by a gas injection molding method using a thermoplastic resin as a material.

The length (L) of the shaft (2) is, for example, 382 mm,
Length L of solid part (5) between empty parts (4,4) ₁Is 110m for example
m, the inscribed circle diameter is, for example, 6 mm, and the total length L of the claw portion (3)_TwoIs an example
For example, it is set to 33 mm.

As the thermoplastic resin used in the present invention, polyethylene, polypropylene, polystyrene, ABS
Resin, polyvinyl chloride, polyamide, polyacetal,
Polycarbonate, modified polyphenylene ether, polyethylene terephthalate, polybutylene terephthalate, polyphenylene sulfide, polyimide, polyamideimide, polyetherimide, polyarylate, polysulfone, polyethersulfone, polyetheretherketone, liquid crystal polymer, polytetrafluoroethylene, thermoplastic Elastomers and the like.

[0013] A fibrous filler may be added to the thermoplastic resin to improve rigidity. Examples of the fibrous filler include glass fiber, carbon fiber, metal fiber, ceramic fiber, asbestos, rock wool, whisker, and aramid fiber. The fibrous filler is usually added in an amount of 10 to 50% by weight based on the thermoplastic resin.

Further, the above thermoplastic resins include calcium carbonate, magnesium carbonate, barium sulfate, calcium sulfate, calcium sulfite, calcium phosphate, calcium hydroxide, magnesium hydroxide, aluminum hydroxide, magnesium oxide, titanium oxide, iron oxide, and iron oxide. Zinc, alumina, silica, diatomaceous earth, dolomite, gypsum, talc, clay, asbestos, mica, glass fiber, calcium silicate, bentonite, white carbon, carbon black, iron powder, aluminum powder, stone powder, blast furnace slag, fly ash Inorganic fillers such as cement, zirconia powder and the like may be added.

The paper feed switching gate (1) is manufactured by a gas injection molding method. A gas injection molding method is to inject a resin melt from a gate into a cavity of an injection mold, and simultaneously or after injection of the resin melt, inject a gas into the resin melt to form a hollow portion in the molded product. The resulting molded article prevents the occurrence of molding defects such as sink marks and warpage due to the gas pressure in the hollow portion. The gas used in this gas injection molding method is, for example, nitrogen, helium,
An inert gas such as neon or argon is desirable, but air or carbon dioxide gas is also used.

In the above gas injection molding method, as shown in FIG. 1, in the shaft molding portion of the cavity of the injection molding die, the injection gate (6) and the gas are placed on the side opposite to the claw (3) insertion side. Communicate with inlet (7). With these settings,
As shown in FIG. 3, the trace of the injection gate and the trace of the gas pressure inlet T on the shaft (2) of the gate (1) to be manufactured are opposite to the claws (3) on the side of the shaft (2). It is formed on the bottom side of the triangular shape, that is, on the side opposite to the paper introduction side. The parting line PL of the mold is a line connecting the vertex of the shaft portion (2) and the tip of the claw portion (3).

The paper feed switching gate (1) is connected to the shaft end (2A, 2A).
A), and is supported in the equipment through the claw part as shown in FIG.
In the state where the leading end of (3) is rotated below the base line BL, the paper is guided upward as shown by the arrow A.
The upper side of the triangular shape of the shaft (2) is along the arrow A, so that the sliding of the paper is not interfered by the triangular corners. As shown in FIG. 5, the paper is guided downward as indicated by the arrow B in a state where the tip of the claw portion (3) is rotated so as to be higher than the base line BL. The lower side of the triangular shape follows the arrow B, so that the sliding of the paper is not interfered by the triangular corners. Further, in both cases shown in FIGS. 4 and 5, the trace of the injection gate and the trace T of the gas pressure inlet are located at the triangular bottom of the shaft (2), so that the trace T interferes with the sliding of the paper. Never. The shape of the claw portion of the gate is appropriately changed according to the purpose of use of the gate. FIG. 6 shows a paper feed switching gate (11) in which a claw (13) of a modified shape is protruded from a shaft (12) having a triangular cross section and having a hollow portion (14) inside.

In addition to this embodiment, the shaft may be entirely solid, or the hollow may extend over the entire length of the shaft. Desired ratio of the length of the hollow section _{L 3 (= L 4 + L} 5) and the shaft portion and the length L is _{0.7 ≦ L 3 / L ≦ 1} , preferably hollow volume V ₁ and the shaft portion of the The ratio of volume V is 0.12 ≧ V
_{1 /} V ≧ 0.07.

The triangular cross section of the shaft portion may be any one of an equilateral triangle, an isosceles triangle, and a non-equilateral triangle.
As shown in FIG. Further, the cross-sectional shape of the shaft portion may be a polygon such as a square, a trapezoid, a pentagon, and a hexagon.

[Test] Using a polycarbonate as a thermoplastic resin, a gate sample having an equilateral triangle and a circular cross section was prepared by injection molding and gas injection molding.
The shape and dimensions of the gate sample having an equilateral triangular cross section are the same as those shown in FIG. 1, and the axis of the gate sample having a circular cross section is 6 mmφ.

The two samples were evaluated for "warpage" and "deflection" by the following method. Table 1 shows the results.

[0022]

[Table 1]

[Warp] Each sample left for 3 days after molding was placed on a glass plate with its warp direction aligned with the vertical direction, and the maximum value (mm) of the distance between the glass plate and the sample was measured. The results are shown in Table 1. The numerical values shown in Table 1 are the average values of five samples.

[Deflection] A load of 100 g was applied to the center of the shaft of each sample which had been left for 3 days after molding, and the amount of deflection (mm) was measured. The sample with a triangular cross section applied the load perpendicular to the base. Table 1 shows the results. The numerical values shown in Table 1 are the average values of five samples.

According to Table 1, in the case of the warp, the sample of the present invention having a triangular shaft section becomes 1 / 1.3 in the case of hollow compared to the comparative sample having a circular cross section in the shaft, but reverse in the case of solid. 1.72
/ 1. Further, in the case of bending, the sample of the present invention having a triangular shaft section is smaller than the comparative sample having a triangular shaft section by a factor of 1 / 3.3 in the case of hollow and 1 / in the case of a solid. 2.8, and the triangular cross-section greatly improves deflection or stiffness.

[0026]

According to the present invention, the rigidity of the shaft portion is extremely increased by the rib effect due to the polygonal cross section, and the paper passage switching gate which is less likely to be warped or bent is manufactured by integrally forming a thermoplastic resin.

[Brief description of the drawings]

 1 to 5 show one embodiment of the present invention.

FIG. 1 is a plan view

FIG. 2 is a cross-sectional view

FIG. 3 is a longitudinal sectional view

FIG. 4 is an explanatory diagram of an upper sheet passing state.

FIG. 5 is an explanatory diagram of a lower sheet passing state.

FIG. 6 is a longitudinal sectional view showing another shape of the claw portion.

FIG. 7 is a longitudinal sectional view showing another sectional shape of the shaft portion.

[Explanation of symbols]

 1 paper passage switching gate 2 shaft 3 claw 4 hollow

Continuation of the front page (72) Inventor Yoji Takano 1900, Ifuna-cho, Suzuka-shi, Mie Prefecture F-term in Suzuka Fuji Xerox Co., Ltd. 3F053 EA02 EA04 EA05 EC02 LA02 LA05 LA07 LB01

Claims (7)

[Claims] 1. A paper passage switching gate, wherein a shaft portion and a claw portion are integrally formed of a thermoplastic resin, and the shaft portion has a polygonal cross section. 2. The paper passage switching gate according to claim 1, wherein the shaft has a triangular cross section. 3. The paper feed switching gate according to claim 2, wherein the shaft portion is arranged with a vertex of a triangular cross section directed in a claw portion feeding direction. 4. The paper passage switching gate according to claim 1, wherein a hollow portion is formed inside the shaft portion. 5. The paper passage switching gate according to claim 1, wherein a fibrous filler is mixed with the thermoplastic resin. 6. A method for manufacturing the paper passage switching gate according to claim 1 by injection molding, wherein a resin melt is injected into a shaft molding portion of a cavity of an injection molding die from a side opposite to a claw portion feeding side. A method for manufacturing a paper passage switching gate, characterized in that: 7. In manufacturing the paper passage switching gate according to claim 4 by a gas injection molding method, a resin melt is formed on a shaft molding portion of a cavity of a gas injection molding die from a side opposite to a claw portion feeding side. And a press-fitting of a gas.