JPH11300850A - Production of cylindrical rubber molded article - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a cylindrical rubber molded article by winding accurately and efficiently an unvulcanized rubber sheet on a mandril without requiring piling up. SOLUTION: Winding processing of an unvulcanized rubber sheet is performed by a method wherein a winding starting end is unwound out by holding it with the first suction pad 3 and is stuck on the outer peripheral face of a mandril 2 and an unvulcanized rubber sheet 1 is wound on the mandril by rotating the mandril 2 while the unvulcanized rubber sheet 1 is unwound out and on the midway of winding, the unvulcanized rubber sheet 1 is held by suction of the first suction pad 3 and the second suction pad 4 arranged in parallel and the unvulcanized rubber sheet 1 is cut between both pads and the next winding starting end is held by suction of the first suction pad 3 and at the same time, the winding terminal end is held by suction of the second suction pad 4 and the unvulcanized rubber sheet is wound on the mandril while the winding terminal end is held by the second suction pad 4 and the winding terminal end held by the second suction pad 4 is stuck on the outer peripheral face of the mandril 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a cylindrical rubber molded article such as an intermediate transfer belt of an electrophotographic apparatus such as a copying machine or a printer or an electrostatic recording apparatus.

[0002]

2. Description of the Related Art Conventionally, in an electrophotographic apparatus such as a copying machine or a printer or an electrostatic recording apparatus, toner is electrostatically attached to an electrostatic latent image formed on the surface of a photoconductor (image forming body). 2. Description of the Related Art An image is formed and transferred to a recording medium such as paper to obtain a printed image.

In recent years, various types of copiers and printers corresponding to color images have been proposed. To obtain a color image, toners of four colors, magenta, yellow, cyan, and black, are superposed at a predetermined ratio. A method of obtaining a color tone is used. In this case, an intermediate transfer belt for temporarily transferring and holding the toner image on the photoconductor is provided as a method for obtaining a predetermined color tone by superimposing the four color toners,
By sequentially transferring four color toner images of a magenta toner image, a yellow toner image, a cyan toner image, and a black toner image onto the intermediate transfer belt, a color image is formed on the intermediate transfer belt.
An intermediate transfer system for transferring this color image onto a recording medium such as paper has been proposed, and some of the intermediate transfer systems have already been implemented.

The intermediate transfer belt used for image formation of the intermediate transfer system is made of a soft and elastic material because it is in direct contact with a photoreceptor, a toner image, a recording medium, and the like. A belt-shaped elastic body is used. In this case, if necessary, the belt is reinforced with a woven fabric or a yarn wound in a spiral shape, or a rib fitted to the drive shaft is projected from the inner surface side of the belt to prevent blurring during rotational driving. Things have also been done.

Conventionally, such a cylindrical rubber molded product such as an intermediate transfer belt has been manufactured by winding an unvulcanized rubber sheet around a cylindrical mandrel and heating and vulcanizing the same to form a cylindrical shape. I have.

[0006]

However, in the conventional manufacturing method, it is difficult to accurately wind the unvulcanized rubber around the mandrel in the step of winding the unvulcanized rubber around the mandrel. Is leaving.

That is, in the step of winding a conventional unvulcanized rubber sheet around a mandrel, as shown in FIG. 4A, the unvulcanized rubber sheet 1 is unwound from a sheet roll r, measured and cut to a predetermined size. Then, as shown in FIG. 4B, the cutting is performed by winding the cut unvulcanized rubber sheet 1 around the outer periphery of the mandrel 2.

However, a single rubber sheet cut from a sheet roll is very difficult to handle because the sheet itself is relatively thin with the above-mentioned intermediate transfer belt or the like, so that it can be wound neatly even when it is wound around the mandrel 2 by hand. Requires considerable skill. In addition, when a winding operation is automatically performed using a winding device, a device having an extremely advanced control mechanism is required.

Further, since the rubber sheet 1 cut out from the sheet roll is in a free state without any tension, it may expand or contract due to the characteristics of raw rubber. When wound around the mandrel 2, the dimensions may change. In this case, when the dimensions are reduced, a gap is formed between the winding start end and the winding end of the mandrel, and it is no longer possible to obtain a cylindrical molded product. For this reason, conventionally, the rubber sheet 1 has been cut slightly larger in consideration of the dimensional change, and as shown by reference numeral b in FIG. The winding end is overlapped by about 2 to 3 mm and wound.

However, when the cylindrical rubber molded product thus obtained is used for an application requiring extremely high precision, such as an intermediate transfer belt, the overlapped portion may cause a defect. .

The present invention has been made in view of the above circumstances, and accurately and efficiently winds an unvulcanized rubber sheet around a mandrel without requiring superposition, thereby stably forming a highly accurate cylindrical rubber molded product. An object of the present invention is to provide a method for producing a cylindrical rubber molded product that can be produced efficiently.

[0012]

In order to achieve the above object, a method for producing a cylindrical rubber molded product according to the present invention is to wind an unvulcanized rubber sheet around the outer periphery of a mandrel and heat and vulcanize the rubber sheet to form a cylindrical rubber molded product. When obtaining the rubber molded product of (1), the winding start end of the unvulcanized rubber sheet is sucked and held by the first suction pad,
(2) The first suction pad is moved to a rotatably supported mandrel to unwind the unvulcanized rubber sheet from the sheet roll, and the first suction pad is used to move the winding start end of the unvulcanized rubber sheet to the mandrel. By pressing against the outer peripheral surface of the unvulcanized rubber sheet, the winding start end of the unvulcanized rubber sheet is attached to the outer peripheral surface of the mandrel, and (3) the unvulcanized rubber sheet is rotated by rotating the mandrel. (4)
At the time when the mandrel is rotated by a predetermined angle, at the position in front of the mandrel, the first suction pad and the second suction pad are adsorbed on an unvulcanized rubber sheet in a state of being arranged in parallel, and the unvulcanized rubber sheet is interposed between the two pads At the same time as forming the winding end and the next winding start end by suctioning, the winding start end is suction-held by the first suction pad, and the winding end is suction-held by the second suction pad. (5) The unvulcanized rubber sheet is wound around the mandrel by rotating the mandrel and moving the second suction pad to the mandrel, and when the mandrel has rotated one turn, the unvulcanized rubber sheet is applied by the second suction pad. The end of winding of the unvulcanized rubber sheet is pressed against the outer peripheral surface of the mandrel to release the suction holding state. Give it to perform.

As described above, according to the manufacturing method of the present invention,
From unwinding of the unvulcanized rubber sheet, pasting of the winding start end, winding of the unvulcanized rubber sheet by rotating the mandrel, cutting of the unvulcanized rubber sheet, and pasting of the winding end, The state where both ends in the winding direction are always held by any of the sheet roll, the first suction pad, the second suction pad, and the mandrel is maintained, and the unvulcanized rubber sheet does not become free until the winding is completed.

Therefore, by controlling the feeding resistance from the sheet roll, the moving speed and the moving force of the first and second suction pads, the rotating speed and the rotating force of the mandrel, etc., the unvulcanized rubber sheet is completely cut and wound. Until then, the winding operation can be performed with a constant tension applied. Thus, the unvulcanized rubber sheet can be accurately cut without considering expansion and contraction, and can be accurately wound around the mandrel without necessity of overlapping the ends.

In addition, since the winding operation is performed while tension is always applied to the unvulcanized rubber sheet, a clean winding finish can be obtained relatively easily, and the driving mechanism of the first and second suction pads and By controlling the rotation mechanism of the mandrel, the winding operation can be easily automated.

Therefore, according to the method for producing a cylindrical rubber formed article of the present invention, an unvulcanized rubber sheet can be accurately and efficiently wound around a mandrel without requiring superposition, and this is heated and vulcanized. By doing so, a highly accurate cylindrical rubber molded product can be stably and efficiently produced.

[0017]

Embodiments and examples of the present invention will be described below.
The present invention will be described more specifically. FIG. 1 shows a step of winding an unvulcanized rubber sheet in a method for producing a cylindrical rubber molded product according to one embodiment of the present invention, and unrolls an unvulcanized rubber sheet 1 from a sheet roll (not shown). Shows the operation of cutting the unvulcanized rubber sheet 1 to a predetermined length, winding it around a mandrel 2, and obtaining a mandrel 2 with the unvulcanized rubber sheet 1 wound around the outer peripheral surface. is there.

In the winding step in the manufacturing method of the present invention, as shown in FIG. 1 (A), first, the tip of the unvulcanized rubber sheet 1 unwound from the sheet roll is moved to the first position.
The mandrel 2 is rotatably supported while being suction-held by the suction pad 3. In this case, as shown in FIG. 1 (A), it is preferable that the leading end portion of the unvulcanized rubber sheet 1 is sucked and held on the first suction pad 3 via the feeding roller 5, and is separated from the feeding roller 5 by a predetermined distance. To support the mandrel 2. The leading end of the unvulcanized rubber sheet 1 sucked and held by the first suction pad 3 serves as a winding start end around the mandrel 2.

Next, the first suction pad 3 is moved to the mandrel 2 side, and the unvulcanized rubber sheet is unwound from a sheet roll (not shown), and as shown in FIG. By pressing the winding start end of the unvulcanized rubber sheet 1 with the first suction pad against the outer peripheral surface of the mandrel 2 coated with an adhesive as necessary, the suction holding state by the first suction pad 3 is released. The winding start end of the unvulcanized rubber sheet 1 is attached to the outer peripheral surface of the mandrel 2.

Then, as shown in FIG. 1 (C), the unvulcanized rubber sheet 1 is wound around a mandrel 2 while being unwound from a sheet roll (not shown) by rotating the mandrel. The rotation of the mandrel 2 is temporarily stopped at the time when the mandrel is rotated by a predetermined angle before the rotation.

After the rotation of the mandrel 2 has stopped, FIG.
As shown in (D), at the position before the mandrel 2, the first suction pad 3 and the second suction pad 4 are adsorbed to the unvulcanized rubber sheet 1 in a state where they are arranged side by side, and both pads 2 , 3 between the unvulcanized rubber sheet 1. As a result, the unvulcanized rubber sheet 1 fed out is cut into a predetermined length to form a winding end and a next winding start end, and at the same time, the winding end is held by the second suction pad 4. Along with
The next winding start end is suction-held by the first suction pad 3. The cutting of the unvulcanized rubber sheet is performed by stopping the rotation of the mandrel 2 by cutting while moving the first and second suction pads 3 and 4 and the cutter at the same speed as the winding speed. Alternatively, it can be performed in parallel with the winding operation.

In this case, the cutting of the unvulcanized rubber sheet 1
It can be performed using an appropriate cutter, and specifically, an electric heating knife or an ultrasonic knife is preferably used. Also,
At the time of cutting, it is preferable to incline the cutter obliquely to make the cut surface oblique. As described later, this makes it possible to securely join the winding start end and the winding end without overlapping the winding end. Further, the unvulcanized rubber sheet 1
The distance between the first suction pad 3 and the second suction pad 4 at the time of cutting is preferably narrow as long as the cutter for cutting can move smoothly and cut.

Next, as shown in FIG.
The unvulcanized rubber sheet 1 is wound around the mandrel 2 while rotating the mandrel 2 to move the second suction pad 4 toward the mandrel 2 again, and the rotation is stopped when the mandrel 2 makes one rotation. Then, the end of winding of the unvulcanized rubber sheet 1 is pressed against the outer peripheral surface of the mandrel 2 by the second suction pad 4 and the suction holding state by the second suction pad 4 is released. Attach the winding end to the outer surface of the mandrel. The end of the winding can be attached without stopping the rotation of the mandrel 2 by performing the attachment while moving the second suction pad 4 at the same speed as the winding speed.

As a result, as shown in FIG. 1 (F), a mandrel 2 having an unvulcanized rubber sheet 1 wrapped around its outer periphery is obtained, which is removed from the rotary drive shaft.
Attach the next mandrel to the rotary drive shaft,
By repeating the operations (A) to (E), the winding operation can be continuously performed while the unvulcanized rubber sheet 1 is unwound from a sheet roll (not shown).

Thus, according to the manufacturing method of the present invention,
From unwinding of the unvulcanized rubber sheet 1, pasting of the winding start end, winding of the unvulcanized rubber sheet 1 by rotation of the mandrel 2, cutting of the unvulcanized rubber sheet 1, and pasting of the winding end, The state where both ends in the winding direction of the vulcanized rubber sheet 1 are always held by any one of a sheet roll (not shown), the first suction pad 3, the second suction pad 4, and the mandrel 2 is maintained. 1 is not in a free state until the winding is completed.

Therefore, the resistance of the feeding from the sheet roll (in this embodiment of FIG. 1, it can be adjusted by the rotation resistance of the feeding roller), the moving speed and the moving force of the first and second suction pads 3 and 4, and the movement of the mandrel 2 By controlling the rotation speed and the rotation force, the winding operation can be performed with a constant tension applied from the cutting of the unvulcanized rubber sheet 1 to the completion of the winding. As a result, the unvulcanized rubber sheet 1 can be obtained without considering the expansion and contraction of the unvulcanized rubber sheet 1.
Can be accurately cut and wound around the mandrel accurately without necessity of overlapping the ends.

Specifically, according to the above method, the accuracy variation a (see FIG. 2) of the seam between the winding start end and the winding end of the unvulcanized rubber sheet 1 can be set to ± 0.1 mm or less. it can. In this case, this degree of variation can be absorbed by cutting the unvulcanized rubber sheet 1 by making the cutter oblique and making the cut surfaces at the winding start end and the winding end oblique. As shown in FIGS. 2A and 2B, the winding start end 6 and the winding end 7 of the unvulcanized rubber sheet 1 are formed.
Can be securely joined to each other, and the joining can be surely performed without the necessity of overlapping. Note that FIG.
FIG. 2B shows a case where the length is about 1 mm longer.
mm.

Further, according to the above-mentioned method, since the winding operation can be performed with the unvulcanized rubber sheet 1 always being tensioned, a clean winding finish can be easily obtained, and the first and second windings can be easily obtained. By controlling the drive mechanism of the suction pads 3 and 4 and the rotation mechanism of the mandrel 2, the winding operation can be easily automated.

In this case, the drive mechanism of the first and second suction pads 3 and 4 and the rotation mechanism of the mandrel 2 are not limited as long as the above-described operation can be reliably performed. Well, it can be designed appropriately. Also, the control means for controlling the driving mechanism and the rotating mechanism may be any means capable of accurately controlling the above-described operation, and may be controlled by a computer using, for example, a servomotor.

Further, the first and second suction pads 3, 4
Any material can be used as long as it can surely hold the rubber sheet by suction, and is not particularly limited. For example, the structure shown in FIG. 3 can be exemplified.

That is, in the suction pad of FIG. 3, a plate body 9 provided with a large number of through holes is attached to the lower end surface of a box-shaped main body 8 having an open lower end surface, and the lower end surface of the box-shaped main body 8 is closed. Further, a porous foam plate 10 is attached to the lower surface of the plate body 9, and the inside of the box-shaped main body 8 is vacuum-sucked, and the rubber sheet is suction-adsorbed to the lower surface of the foam plate 10. . According to this suction pad, by suctioning the inside of the box-shaped main body 8 by vacuum, the entire lower surface of the foam plate 10 is uniformly sucked by the action of the plate body 9 and the foam plate 10, so that the rubber sheet is 10
The rubber sheet can be stably held by uniformly sucking and adsorbing the entire lower surface of the rubber sheet.

In the production method of the present invention, the unvulcanized rubber sheet 1 wound around the mandrel 2 as described above is heated and vulcanized to obtain a cylindrical rubber molded product. There is no particular limitation, and a known method such as so-called bladder vulcanization may be used, for example, using a vulcanizing pot equipped with a rubber bladder. According to the production method of the present invention, by heating and vulcanizing the unvulcanized rubber sheet wound around the mandrel 2 as described above, a highly accurate cylindrical rubber molded product can be produced stably and efficiently. You can do it.

The method for producing a cylindrical rubber formed article of the present invention is not limited to the above-described embodiment, and various modifications may be made within the scope of the present invention. Further, the manufacturing method of the present invention is preferably employed when manufacturing an intermediate transfer belt used in an electrophotographic apparatus such as a copying machine or a printer or an electrostatic recording apparatus, but is not limited thereto. However, the present invention is also suitably used when manufacturing a cylindrical rubber molded product such as an air spring, a timing belt, and other small belts.

[0034]

As described above, according to the method for producing a cylindrical rubber formed article of the present invention, an unvulcanized rubber sheet can be accurately and efficiently wound around a mandrel without requiring superposition. By heating and vulcanizing this, a highly accurate cylindrical rubber molded product can be stably and efficiently produced.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram for sequentially explaining a procedure for winding an unvulcanized rubber sheet around a mandrel in the method for producing a cylindrical rubber molded product of the present invention.

FIG. 2 is a cross-sectional view showing a state in which a winding start end and a winding end of a rubber sheet wound around a mandrel by the same procedure are abutted.

FIG. 3 is a schematic exploded view showing an example of first and second suction pads used in the manufacturing method of the present invention.

FIG. 4 is a schematic perspective view illustrating a conventional procedure for winding an unvulcanized rubber sheet around a mandrel.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Unvulcanized rubber sheet 2 Mandrel 3 1st suction pad 4 2nd suction pad 5 Feeding roller 6 Winding start end 7 Winding end

Claims (2)

[Claims] 1. A method for producing a cylindrical rubber molded product, wherein an unvulcanized rubber sheet is wound around an outer periphery of a mandrel, and the rubber sheet is heated and vulcanized to obtain a cylindrical rubber molded product. The winding start end is sucked and held by the first suction pad, and the first suction pad is moved to a rotatably supported mandrel to feed out the unvulcanized rubber sheet from the sheet roll. By pressing the winding start end of the vulcanized rubber sheet against the outer peripheral surface of the mandrel to release the suction holding state, the winding start end of the unvulcanized rubber sheet is attached to the outer peripheral surface of the mandrel, and the mandrel is rotated. The vulcanized rubber sheet is wound around a mandrel while being fed out from a sheet roll, and when the mandrel is rotated by a predetermined angle, the first suction pad is positioned at a position before the mandrel. And the second suction pad are arranged side by side and adsorbed on an unvulcanized rubber sheet, and by cutting the unvulcanized rubber sheet between both pads, a winding end and a next winding start end are formed, The winding start end is sucked and held by the first suction pad, and the winding end is set to the second suction pad.
While holding the suction pad with a suction pad, rotating the mandrel again and moving the second suction pad to the mandrel, winding an unvulcanized rubber sheet, stopping the rotation when the mandrel makes one rotation, 2 By pressing the winding end of the unvulcanized rubber sheet against the outer peripheral surface of the mandrel with the suction pad to release the suction holding state, the winding end of the unvulcanized rubber sheet is attached to the outer peripheral surface of the mandrel, A method for producing a cylindrical rubber molded product, comprising winding a vulcanized rubber sheet. 2. The process from unwinding of an unvulcanized rubber sheet, pasting of a winding start end, winding of an unvulcanized rubber sheet by rotating a mandrel, cutting of an unvulcanized rubber sheet, and pasting of a winding end. 2. The method according to claim 1, wherein the vulcanized rubber sheet is held at a constant tension.