JP2001347562A - Manufacturing method for tubular film, and molding die - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for tubular film which can easily make uniform a gap between a tubular die member and a columnar member when the film is molded and can make uniform the thickness of the molded tubular film. SOLUTION: A sheetlike film 4 of a thermoplastic resin wound like a roll on the columnar member 2 is inserted into the tubular die member 3 having an inside diameter slightly larger than the outside diameter of the columnar member 2 and is molded by heating, so as to manufacture the tubular film. In this method of manufacturing the tubular film, a spacer 7 stipulating the gap between the outer peripheral surface of the columnar member 2 and the inner peripheral surface of the tubular die member 3 is provided in the end part of at least either the columnar member 2 or the tubular die member 3, and the sheetlike film is molded by using the columnar member 2 and the tubular die member 3 either of which is provided with the spacer 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer belt used for transferring a precision part to a predetermined position with a high degree of positional accuracy, and a closed package for storing and storing articles. The present invention relates to a method for producing a tubular, tubular, ring-shaped or belt-shaped film, and a mold, and is mainly used for producing a functional component of an image forming apparatus.

[0002] A tubular film manufactured by a tubular film manufacturing apparatus using the present invention is used as a transfer belt of a copying machine, a printer or the like.

[0003]

2. Description of the Related Art In a conventional method of manufacturing a tubular film, in a step of forming a seamless belt using a tubular mold member and a cylindrical member by utilizing a difference in thermal expansion between the tubular mold member and the cylindrical member, the tubular mold member and the cylindrical member are formed. By setting the sheet for molding in the gap of, and heating the whole above the melting temperature of the film, the gap between the tubular member having a small coefficient of thermal expansion and the cylindrical member having a large coefficient of thermal expansion was narrowed, and the gap was adapted. It was molded to a substantially uniform thickness (see FIGS. 3, 4, 6, and 7).

[0004]

However, the conventional method for producing a tubular film has the following problems.

(1) A conventional sheet-like film for molding is wound around a cylindrical member once or a plurality of times and inserted into a tubular mold member, and a sheet-like film is formed by utilizing a difference in thermal expansion between the tubular mold member and the cylindrical member. In the method of forming the seamless belt by crushing the overlapping portion at the end of the film, it has been difficult to form the overlapping portion to have substantially the same thickness as the portion other than the peripheral overlapping portion. In addition, it was difficult to crush and flow the thickness unevenness of the sheet-like film for molding so that the entire film was formed to have substantially the same thickness. (2) Extrusion of a conventional tubular film for molding,
Or by centrifugal molding, after covering the cylindrical member, inserted into the tubular mold member, in the method of forming a seamless belt using the difference in thermal expansion between the tubular mold member and the cylindrical member, the tubular film of the material Crush thickness unevenness and make it flow,
It was difficult to mold the whole to almost the same thickness. (3) In any of the above methods (1) and (2), when a molding sheet is set in the gap between the tubular mold member and the cylindrical member at room temperature, the gap between the tubular mold member and the cylindrical member is reduced. Since the gap is often not uniform, even when the film is heated to the melting temperature, the gap between the tubular mold member and the cylindrical member is not uniform, so that the whole can be formed to have substantially the same thickness. was difficult.

[0006] The tubular film produced by the above method is
When used as a transfer belt for copying machines, printers, and the like, unevenness in the thickness causes a distribution in the applied voltage of the belt and the distance to the transfer drum. I was

Accordingly, the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to easily uniform a gap between a tubular mold member and a cylindrical member at the time of film forming, and to form a tubular film after forming. It is an object of the present invention to provide a method for producing a tubular film and a molding die capable of making the thickness of the film uniform.

[0008]

Means for Solving the Problems The above-mentioned problems are solved,
In order to achieve the object, a method for producing a tubular film according to the present invention is to provide a sheet-shaped film of a thermoplastic resin wound in a roll shape on a cylindrical member having an inner diameter slightly larger than the outer diameter of the cylindrical member. A method for producing a tubular film for producing a tubular film by inserting into a tubular mold member and performing heat molding, wherein at least one end of the cylindrical member or the tubular mold member has a cylindrical member. A spacer defining a gap between an outer peripheral surface and an inner peripheral surface of the tubular mold member is provided, and the sheet-like film is formed using a cylindrical member or a tubular mold member provided with the spacer.

In the method of manufacturing a tubular film according to the present invention, the spacer is formed in one or a plurality of strips.

[0010] In the method of manufacturing a tubular film according to the present invention, the spacer comprises a step formed on the cylindrical member or the tubular mold member.

In the method for manufacturing a tubular film according to the present invention, a hole or a groove is formed in the step portion.

Further, a mold for forming a tubular film according to the present invention is a tubular member comprising: a cylindrical member for winding a sheet film of a thermoplastic resin; and a tubular member for inserting the cylindrical member wound with the sheet film. A film forming die, wherein at least one end of the cylindrical member or the tubular mold member is provided with a spacer that defines a gap between an outer peripheral surface of the cylindrical member and an inner peripheral surface of the tubular mold member. It is characterized by that.

[0013] In the mold for forming a tubular film according to the present invention, the spacer is formed in one or a plurality of strips.

Further, in the mold for forming a tubular film according to the present invention, the spacer comprises a step formed on the cylindrical member or the tubular mold member.

Further, in the mold for forming a tubular film according to the present invention, a hole or a groove is formed in the step portion.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described.

First, the outline of the present embodiment will be described. In the present embodiment, in order to make the thickness of the tubular film uniform, the gap between the tubular mold member and the cylindrical member at the time of heating to the molding temperature is kept constant. The thickness of the formed tubular film can be made uniform.

In addition, when heated to the molding temperature, a spacer that keeps the gap between the tubular mold member and the cylindrical member constant, and the heated air collects between the spacer and the molded film, and the end of the film deteriorates and deteriorates. In order to prevent this, holes or grooves for allowing air to escape are provided.

If it is difficult to insert a spacer as a means for making the thickness of the tubular film uniform when a sheet for molding is set in the gap between the tubular mold member and the cylindrical member, A step is provided on one or both of the and the cylindrical member.

Hereinafter, a specific description will be given with reference to the drawings.

FIG. 1 is a view showing a manufacturing process of a tubular film according to the present embodiment. 1 is a thermoplastic resin film wound in a roll shape, 2 is an inner mold, 3 is a tubular mold member, and 4 and 5 are A thermoplastic resin sheet film, 4 'and 5' are thermoplastic resin tubular films, and 6 is a cooling unit. Here, a coolant in which tap water is stored in a water tank is used, but other liquids may be used as long as they do not affect the cooling air, the inner mold, the tubular film, and the tubular mold member.

Next, a procedure for manufacturing a tubular film will be described.

The dimensions of the sheet film are selected according to the inner diameter of the tubular film to be manufactured, and the sizes of the inner mold 2 and the tubular mold member 3 are selected accordingly. First, in a (1) peeling step of FIG. 1, the thermoplastic resin film 1 wound into a roll is peeled off from the roll, and (2) a cutting step is performed to cut two kinds of sheet-like films 4 and 5. Create Next, in a winding step (3), the sheet-shaped film 4 prepared on the outer peripheral surface of the inner mold 2 is wound so that both ends thereof are overlapped. The width of the overlapping portion at both ends of the film 4 is about 4.0 mm.

Next, the sheet-like film 5 prepared on the outer peripheral surface of the inner mold 2 on which the film 4 is wound is placed so that both ends thereof are overlapped, and the overlapping portion is opposite to the overlapping portion of the film 4. And wrap it around. The width of the overlapping portion at both ends of the film 5 is also about 4.0 mm.

Next, (4) The films 4 and 5 wound around the inner mold 2 in the inserting step are inserted into the hollow portion of the tubular mold member 3 as shown in FIG. (5) In the heating step, the inner mold 2, the films 4, 5 and the tubular mold member 3 are placed in a heating furnace and heated. The heating time is determined in consideration of the melting temperature of the film material and the state of thermal degradation of the film. The inner mold 2, the films 4, 5 and the tubular mold member 3 are heated to increase the temperature of each member, and the inner mold 2 and the tubular mold member 3 expand according to their respective thermal expansion coefficients. Films 4 and 5 begin to soften with increasing temperature. Since the inner mold 2 has a larger thermal expansion coefficient than the tubular mold member 3, as the temperature rises, the dimensional gap between the outer diameter of the inner mold 2 and the inner diameter of the tubular mold member 3 becomes narrower than in the initial low temperature state.

With the narrowing of the gap between the inner mold and the tubular mold member, the films 4 and 5 sandwiched therebetween are further softened, and the overlapping portion is extended in the circumferential direction of the inner mold 2 due to the decrease in the gap, and the overlapping portion is formed. They are welded to each other to be joined. Note that the gap between the inner mold and the tubular mold member finally becomes substantially the same as the desired film thickness, and the step at the overlapped portion disappears apparently. Thereafter, the spread of the film thickness over the entire film is adjusted by reducing the gap between the inner mold 2 and the tubular mold member 3 due to the expansion of the inner mold 2 and the tubular mold member 3 by maintaining the heated state at a predetermined temperature. After the elapse of the above heating time, the heating is stopped, and the process proceeds to a cooling step.

In the cooling step, the inner mold 2, the tubular film 4 'and the inner mold 2 are cooled naturally after the heating in the heating step is stopped.
5 ′, the tubular mold member 3 may be cooled, but may be cooled rapidly to shorten the cooling time. In this embodiment, after heating,
(5) As in the cooling step, cool by immersing in tap water in a liquid tank. After cooling to a cooling temperature near room temperature,
(6) The inner mold 2 is removed from the tubular mold member 3 in the step of removing the inner mold. At this time, the film is stuck to the outside of the inner mold 2 or the inside of the tubular mold member 3 in a cylindrical shape, and the overlap portion of the first sheet-like film is also joined neatly.

Next, in the step (7) of peeling off from the tubular mold member and cutting off the end portions, the tubular films 4 'and 5' are peeled off from the inner mold 2 or the tubular mold member 3 and the end portions are cut off.

FIG. 3 is a state diagram showing a state in which a sheet-like film is wound around an inner mold at room temperature and inserted into a tubular mold member by a conventional method, and FIG.
FIG. 4 is a state diagram showing a state in which a molding film formed by extrusion molding is inserted into an inner mold at room temperature and inserted into a tubular mold member. It is inserted with a slant inside.

FIG. 5 is a diagram showing a state in which the film is wound inside at normal temperature and inserted into the tubular mold member according to the method of the present embodiment, and FIG. FIG. 7 is a state diagram showing a state inside the mold at a molding temperature when the mold is wound around and inserted into a tubular mold member.
Is a conventional method, centrifugal molding, or molding film formed by extrusion molding is inserted into the inner mold at room temperature,
FIG. 8 is a state diagram showing a state in a mold at a molding temperature when inserted into a tubular mold member, and FIG.
FIG. 4 is a state diagram showing a state in a mold at a molding temperature when a film is wound inside at normal temperature and inserted into a tubular mold member.

3, 4, 5, 6, 7 and 8, 2 is an inner mold, 3 is a tubular mold member, 4 is a sheet-like film wound around the inner mold, and 4 'is a molding temperature. Is a tubular film.

In the conventional method, the forming film set at room temperature as shown in FIG. 3 does not become a tubular film having a completely uniform thickness even at the forming temperature as shown in FIG. Unevenness is about 30 μm.

Next, the method for manufacturing the tubular film according to the present embodiment will be specifically described with reference to FIGS.

In FIG. 5, the material of the tubular mold member 3 is S
K material, linear expansion coefficient is 1.1 × 10 ^-Five(1 / K), inner mold
The linear expansion coefficient of the hollow cylinder 2 (made of PTFE) is 12.5 ×
10 ^-Five(1 / K). At room temperature (25 ° C), tubular mold
The inner diameter of the material 3 is 68.00 mm, and the outer diameter of the inner mold is 6
It is 6.63 mm. 7 is a spacer made of SK material
And the coefficient of linear expansion is 1.1 × 10^-Five(1 / K) and the thickness
The size is 0.15 mm.

This was heated in an electric furnace at a molding temperature of 165 (° C.).
When heated to the degree, the linear expansion calculation formula (diameter after heating) = (diameter before heating) + (diameter before heating) × linear expansion coefficient × (temperature after heating−temperature before heating) shows that the inner diameter of the tubular mold member 3 is 68. .00 + 68.00 × 1.1 × 10 ⁻⁵ × (165-2
5) = 68.10 mm

The outer diameter of the inner mold 2 is 66.63 + 66.63 × 12.5 × 10 ⁻⁵ × (165-2
5) = 67.80 mm

The thickness of the spacer 7 is 0.15 + 0.15 × 1.1 × 10 ⁻⁵ × (165-25) =
0.1502 mm ≒ 0.15 mm.

The state in which the sheet-like film 4 is wound around the inner mold 2 and inserted into the tubular mold member 3 is as shown in FIG. 5 and as shown in FIG. 7 at the molding temperature.
At the molding temperature, the gap between the tubular mold member 3 and the inner mold 2 is made uniform over the entire mold as shown in FIG. 8, and the film material spreads all over the uniformed gap. The difference between the inner diameter of the tubular mold member 3 and the outer diameter of the inner mold 2 during heating is 68.10-67.
80 = 0.3 mm, which is almost equal to twice the thickness of the spacer 7. Therefore, the thickness of the film at the time of molding,
0.3 / 2 = 0.15 mm.

When the tubular film was formed by the above-mentioned method, the thickness of the formed tubular film was 0.147 to 0.1 mm.
It was 153 mm, and a tubular film with extremely small thickness unevenness could be obtained.

Finally, the tubular film manufactured by the tubular film manufacturing apparatus using the present embodiment is used as a transfer belt of a copying machine, a printer, and the like.

In FIG. 2, 4 'and 5' are transfer belts,
51 is a charging drum, 52 is a transfer drum, 53 is a developing roller, 54 is a transfer and transport roller, 55 is copy paper, 5
Reference numeral 6 denotes a toner, and the transfer belts 4 ′ and 5 ′ are applied to a transfer / transport roller 54. First, the charging drum 51
As a result, an image voltage is applied to the transfer drum 52. Next, toner is supplied to the transfer drum 52 from the developing roller 53, and the toner is transferred in the form of an image. Here, the copy paper 55 is supplied by the transfer belts 4 ′ and 5 ′, and the toner is transferred from the transfer drum to the copy paper. Although the copy paper on which the toner has been transferred is not shown,
It is carried to the fixing section. When a transfer belt manufactured using the molding method of the present embodiment was used in the image forming process, an image with less unevenness could be formed than a transfer belt using a conventional molding method.

[Other Embodiments] (1) A tape-shaped SK material member 8 is used as a spacer, and the action of making the gap between the tubular mold member 3 and the inner mold 2 uniform at the molding temperature is performed. As a result, the number of spacers was reduced, and the labor for mounting the spacers was reduced (see FIG. 9). (2) Instead of the spacer, the inner peripheral end of the tubular mold member 3;
Steps 9 and 10 were provided at the outer peripheral end of the inner mold 2 to make the gap between the tubular mold member 3 and the inner mold 2 uniform at the molding temperature. At this time, grooves 11 and 10 were provided to prevent high-temperature air from accumulating between the film and the step portion and to prevent the end portion of the film from being deteriorated or deteriorated. This saves time and effort for mounting the spacer (see FIG. 10). (3) In place of the spacer, a step 9 is provided at the inner peripheral end of the tubular mold member 3 to make the gap between the tubular mold member 3 and the inner mold 2 uniform at the molding temperature. At this time, high-temperature air accumulates between the film and the step, deteriorating the film edge,
A groove 11 for preventing deterioration is provided in the step portion 9. Thereby, the thickness unevenness of the formed tubular film is improved to about ± 10 μm as compared with the case where the means for attaching the spacer is omitted and the means for equalizing the gap between the tubular mold member and the inner mold is not used (see FIG. 11). . (4) In place of the spacer, a step 10 is provided at the outer peripheral end of the inner mold 2 to make the gap between the tubular mold member 3 and the inner mold 2 uniform at the molding temperature. At this time, a groove 11 for preventing high-temperature air from accumulating between the film and the step portion and deteriorating and deteriorating the end portion of the film was provided in the step portion 10.
Thereby, the thickness unevenness of the formed tubular film is improved to about ± 10 μm as compared with the case where the means for attaching the spacer is omitted and the means for equalizing the gap between the tubular mold member and the inner mold is not used (see FIG. 12). . (5) Instead of the spacer, the inner peripheral end of the tubular mold member 3;
Steps 9 and 10 were provided at the outer peripheral end of the inner mold 2 to make the gap between the tubular mold member 3 and the inner mold 2 uniform at the molding temperature. At this time, holes 12 were provided in the steps 9 and 10 to prevent high-temperature air from accumulating between the film and the steps, and to prevent deterioration and deterioration of the film end. This saves time and effort for mounting the spacer (see FIG. 13).

[0043]

As described above, according to the present invention,
At the time of film forming, the gap between the tubular mold member and the cylindrical member can be easily made uniform, and the thickness of the formed tubular film can be made uniform.

[Brief description of the drawings]

FIG. 1 is a view showing a manufacturing process of a tubular film in one embodiment of the present invention.

FIG. 2 is a view showing a use form of a tubular film in one embodiment of the present invention.

FIG. 3 is a state diagram showing a state in which a sheet-like film is wound around an inner mold at room temperature and inserted into a tubular mold member according to a conventional method.

FIG. 4 is a state diagram showing a state in which a molding film molded by centrifugal molding or extrusion molding by a conventional method is fitted into an inner mold at room temperature and inserted into a tubular mold member.

FIG. 5 is a diagram showing a state in which a film is wound inside at normal temperature and inserted into a tubular mold member according to the method of one embodiment of the present invention.

FIG. 6 is a state diagram showing a state in a mold at a molding temperature when a sheet-like film is wound around an inner mold at room temperature and inserted into a tubular mold member according to a conventional method.

FIG. 7 is a state diagram showing a state in a mold at a molding temperature when a molding film molded by centrifugal molding or extrusion molding according to a conventional method is fitted into an inner mold at room temperature and inserted into a tubular mold member. It is.

FIG. 8 is a state diagram showing a state in a mold at a molding temperature when a film is wound inside at normal temperature and inserted into a tubular mold member according to the method of one embodiment of the present invention.

FIG. 9 is a diagram showing another embodiment 1.

FIG. 10 is a view showing another embodiment 2.

FIG. 11 is a view showing another embodiment 3.

FIG. 12 is a view showing another embodiment 4.

FIG. 13 is a view showing another embodiment 5.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 roll of thermoplastic resin film 2 inner mold 3 tubular mold member 4, 5 sheet film 4 ′, 5 ′ tubular film 6 cooling section 7 spacer 8 tape-shaped spacer 9 outer mold step 10 inside Mold step 11 Groove 12 Hole 51 Charging drum 52 Transfer drum 53 Developing roller 54 Transfer / transport roller 55 Copy paper 56 Toner

Claims (8)

[Claims] 1. A sheet-like film of a thermoplastic resin wound in a roll shape around a cylindrical member is inserted into a tubular mold member having an inner diameter slightly larger than the outer diameter of the cylindrical member, and is formed by heat molding. A method for producing a tubular film for producing a film, wherein at least one end of the cylindrical member or the tubular mold member has an outer peripheral surface of the cylindrical member and an inner peripheral surface of the tubular mold member. A method for manufacturing a tubular film, comprising: providing a spacer for defining a gap; and forming the sheet-like film using a cylindrical member or a tubular mold member provided with the spacer. 2. The method according to claim 1, wherein the spacer is formed in one or a plurality of strips. 3. The method according to claim 1, wherein the spacer comprises a step formed on the columnar member or the tubular mold member. 4. The method according to claim 3, wherein a hole or a groove is formed in the step. 5. A mold for forming a tubular film, comprising: a cylindrical member for winding a sheet-like film of a thermoplastic resin; and a tubular mold member into which the cylindrical member on which the sheet-like film is wound is inserted. Or a mold for forming a tubular film, wherein at least one end of the tubular mold member is provided with a spacer for defining a gap between an outer peripheral surface of the cylindrical member and an inner peripheral surface of the tubular mold member. . 6. The mold according to claim 5, wherein the spacer is formed in one or a plurality of strips. 7. The mold according to claim 5, wherein the spacer comprises a step formed on the cylindrical member or the tubular mold member. 8. The mold according to claim 7, wherein a hole or a groove is formed in the step.