JP2837633B2 - Partingless roller manufacturing equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for manufacturing a partingless roller such as a developing roller or a transfer roller used in an electronic copying machine.

[0002]

2. Description of the Related Art In recent years, as electronic copiers and laser printers have become widespread, equipment has been reduced in size due to space-saving installations.
In response to the demand for weight reduction, various types of rubber rollers used in such devices are also required to be reduced in size, dimensional precision, and surface polishing precision for printing.

However, the electronic function rubber roller is provided with a part formed by a two-piece upper and lower mold, which is a conventional manufacturing method, that is, the parting between the upper and lower molds along the longitudinal direction on both sides of the outer peripheral surface of the rubber roller. However, even if the surface is polished with high precision, there is a technical limit, and a problem occurs in printing.

[0004] In view of the above, various apparatuses for manufacturing a parting-less roller as disclosed in Japanese Patent Application Laid-Open Nos. 1-135608 and 4-320213 have been proposed.

In this manufacturing apparatus, a seamless pipe 4 is mounted in a cavity 3 formed between upper and lower molds 1 and 2 as shown in FIG. The metal core 7 held by the metal core holding members 5 and 6 is inserted.

The lower die 2 is provided with a rubber injection hole 9 communicating with a circumferential groove 8 formed in the right-hand core metal holding member 5.

Then, a heat vulcanized unvulcanized silicone rubber is press-filled from the rubber injection hole 9 through the circumferential groove 8 into the gap 10 between the seamless pipe 4 and the metal core 7, and then heated to vulcanize. Molding. In this way, a non-polished single-layer silicone rubber roller is obtained.

[0008]

By the way, in order to manufacture the above-mentioned rubber roller, vulcanization molding must be performed, but in order to improve productivity, vulcanization molding at high temperature and for a short time is required. Has been requested.

However, in the prior art described in each of the above publications, the higher the vulcanization molding temperature, the higher the internal pressure of expansion of the cavity.
Or vulcanized rubber is pushed out from the rubber injection hole 9, and in some cases, the rubber in the vicinity of the injection hole 9 is scattered in powder form,
There is a possibility that the rubber of the roller body may be peeled off.

Furthermore, due to the high internal pressure of the cavity 3, the lower pipe 2 opens the seamless pipe 4 after the mold is opened.
When removing the seamless pipe 4, the seamless pipe 4 must be peeled off using a tool such as a bar. As a result, the taking-out work becomes complicated, and the outer periphery of the metal core holding members 5 and 6 at both ends of the seamless pipe 4 is easily damaged, so that the complicated replacement work of the metal core holding members 5 and 6 is inevitable. .

[0011]

SUMMARY OF THE INVENTION The present invention has been devised in view of the above-mentioned conventional problems, and the invention of claim 1 is mounted in a cavity between split molds for vulcanization molding. A seamless pipe; a spring absorbing means provided at one end of the seamless pipe for absorbing the internal pressure of expansion of the cavity at the time of vulcanization molding of the unvulcanized rubber filled in the seamless pipe; And a pressure reducing means provided on the other end side for gradually reducing an equalizing pressure between the internal pressure of expansion of the cavity and the spring force of the spring absorbing means when the split mold is opened.

The invention according to a second aspect is characterized in that a variable means for varying the spring force of the spring absorbing means is provided.

[0013]

According to the present invention, in order to form a rubber roller,
An unvulcanized rubber is filled in advance into a seamless pipe whose both ends are closed, and the seamless pipe is mounted in a cavity between split molds. Thereafter, the spring setting load of the spring absorbing means, that is, the initial load on the unvulcanized rubber in the seamless pipe is set by the variable means. Thereafter, when high-temperature vulcanization molding is performed, excessive expansion internal pressure of the cavity is suppressed by the spring absorbing means.

When the mold is opened after the vulcanization molding, the pressure between the cavity expansion internal pressure and the spring force of the spring absorbing means is gradually reduced by the pressure reducing means. Therefore, when the mold opening is completed, the seamless pipe is completely free from any pressure. Therefore, the seamless pipe can be easily removed from the mold.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows an embodiment of an apparatus for manufacturing a parting-less roller according to the present invention, wherein a seamless pipe 11 whose both sides are closed by core metal holding members 12 and 13 is shown.
During the vulcanization molding, the seamless pipe 11
Upper and lower split molds 14 and 15 for vulcanization molding mounted in 6
A spring absorbing means 17 provided at one end of a lower mold 15 on the right end side of the seamless pipe 11 in the drawing; a pressure reducing means 18 provided at the other end of the lower mold 15;
And the variable means 19 provided at the end of.

The seamless pipe 11 is made of a metal material having a predetermined length, as shown in FIG. 3, and has a rod-shaped metal core 20 having both ends held by metal core holding members 12 and 13 inside. It is inserted and arranged along the center direction. The two metal core holding members 12, 13 are opposed to the inner end portions 12a, 1
The outer periphery of 3a is cut out in an annular shape, and the inner peripheral portion 13a of the cored metal holding member 13 on the right side in the drawing has grooves 21a and 21b formed by turning air and rubber around the outer periphery and the outer periphery. On the other hand, the cored metal holding member 12 on the left side in the drawing has an injection groove 22a having a substantially trapezoidal cross section at the center position of the outer end face, and the inside of the seamless pipe 11 and the injection groove 2a in the inner axial direction.
Injection holes 22b, 22b communicating with 2a are formed through.

Further, inside the seamless pipe 11,
The unvulcanized rubber 24 is filled in advance by the injection machine 23 shown in FIG. That is, the injection machine 23 includes a fixed cylinder 25 for holding the outer periphery of the seamless pipe 11 and the fixed cylinder 25.
It comprises upper and lower lids 26 and 27 provided at the upper and lower ends, and an injection cylinder 28 for injecting the unvulcanized rubber 24 into the seamless pipe 11. The lower lid 27 is
An annular groove 27 communicating with the inverted groove 21b at the outer periphery of the outer end.
a is formed, and an annular groove 27a is formed in the inner axial direction.
An escape passage 27b is formed to communicate the outside with the outside. On the other hand, the upper lid 26 has a communication hole 26a for communicating the injection port 28a of the injection cylinder 28 with the injection groove 22a.
Are formed through. The injection cylinder 28 is provided with a piston 31 for slidably compressing and discharging the unvulcanized rubber 24 via a piston rod 30 inside a cylinder body 29.

As shown in FIG. 1, the upper and lower split dies 14, 15 are fixed to an upper press mounting plate 32 and a lower press mounting plate 33, respectively. A fitting groove 14a into which the upper part of the means 17 fits is formed, and an engaging groove 14b with which the upper part of the pressure reducing means 18 engages is formed at the other end. On the other hand, the lower mold 15
In one of the upper surfaces, a fitting fixing groove 15a in which the lower part of the spring absorbing means 17 is fitted and fixed, and an engaging fixing groove 15b in which the lower part of the pressure reducing means 18 is engaged and fixed are formed at the other end. ing.

As shown in FIGS. 1 and 2, the spring absorbing means 17 has a cylindrical portion 34 having a flange 34a at its front end.
, A push pin 35 is slidably provided. The push pin 35 has a stepped cylindrical shape, and a large-diameter portion 35a on the front end side, which protrudes and retracts from a front end opening 34b of the cylindrical portion 34, is disposed in contact with the rear surface of the right core metal holding member 13, and A coil spring 36 wound around the outer periphery of a small diameter portion 35b provided at the rear end of the diameter portion 35a and elastically mounted between a central flange portion 35c and an adjust nut 37 which will be described later and constitutes a part of the variable means 19. Has been biased forward.

The variable means 19 comprises the adjusting nut 37 screwed to the rear end of the cylindrical portion 34, and a hexagonal locking hole 38 formed at the center of the outer surface of the adjusting nut 37. . The adjusting nut 37 is
A male screw 37a screwed to a female screw formed on the inner periphery of the outer end portion of the cylindrical portion 34 is formed on the outer periphery, and advances and retreats with left and right turning to change the spring setting force of the coil spring 36. .

The pressure reducing means 18 is provided with the engagement fixing groove 15.
b, a slide core 39 slidable back and forth (in the direction of the arrow), and a guide member 4 for guiding the slide core 39
0. The slide core 39 is located on the upper outer end face 3.
9a is formed in a tapered shape having the same angle as the tapered surface 14c of the engagement groove 14b, and is pressed against the seamless pipe 11 while the tapered surface 14c is in sliding contact with the outer end surface 39a at the time of mold clamping. The seamless pipe 11 is pressed against the spring force of the coil spring 36 via the core holding member 12 on the right side.

Hereinafter, a basic method of manufacturing the rubber roller according to the present embodiment will be described.

First, in the first stage of the manufacturing, as shown in FIG.
The core metal 20 is inserted and held through the second and the second 13. In the second stage, the seamless pipe 11 is mounted on the injection machine 23 as shown in FIG.
Is extruded by the piston 31 and injected into the gap S between the seamless pipe 11 and the core metal 20 from the injection port 28a and the communication hole 26a via the injection groove 22a and the injection hole 22b. When the injection of the unvulcanized rubber 24 is completed, the unvulcanized rubber 24 in the seamless pipe 11 is turned upside down and the grooves 21a, 21
b and reversely flow out of the passage 27b.

As described above, the fact that the injection step can be separated does not mean that the unvulcanized rubber is injected into a high-temperature vulcanization mold as in other molding methods, for example, injection molding or transfer molding. Low temperature (40 ° C to 90 ° C)
Injection can be performed at a pressure suitable for the flow. This is also advantageous in terms of rubber material management. Also,
The fact that the temperature of the injected unvulcanized rubber is low means that the difference between the temperature of the vulcanization molds 14 and 15 is large, so that the temperature difference (Δ ° C.) of the rubber compound is also large, and the cavity 1
Since the internal pressure of 6 becomes higher, the quality accuracy of the molded product is improved.

Next, in a third stage, the seamless pipe 11 filled with the unvulcanized rubber 24 is filled with the cavities 16 of the upper and lower dies 14, 15 as vulcanization molds as shown in FIG.
Install inside. That is, the seamless pipe 11 is set in the semi-cylindrical groove-shaped cavity 16a of the lower mold 15 with the upper mold 14 opened as shown in FIG. That is, the slide pin 39 is set between the free state of the slide core 39 and the front end face of the large diameter portion 35a of the push pin 35 on the opposite side. When the upper mold 14 is lowered from the set state, the engaging grooves 14b and the fitting grooves 14a are fitted into the respective upper portions of the spring absorbing means 17 and the pressure reducing means 18. At this time, the engaging grooves 14b
The slide core 39 is advanced rightward in the figure by the tapered surface 14c.

Here, the upper mold 14 and the lower mold 15 are
The mold is clamped by a press. At this time, a heater is attached to a hot platen of the press or upper and lower dies 14, 15 to serve as a heat source.

Then, the unvulcanized rubber 24 in the seamless pipe 11 is vulcanized and formed for a specified time by the heat and pressure of the upper and lower dies 14, 15. The expansion internal pressure of the cavity 16 generated at this time is absorbed by the spring force of the coil spring 36, but the spring force is adjusted in advance by the adjustment nut 37,
Molding is performed while applying optimum pressure to the molded rubber.

Hereinafter, experimental examples 1 to 4 based on the above-described basic operation and comparative examples with the conventional example shown in FIG. 6 will be described.

In Experimental Examples 1 to 3, the spring constant of the coil spring 36 was set to 68 kgf / mm, and in Experimental Example 4, it was set to 90 kgf / mm. The rubber material used was a peroxide vulcanization system of EPDM, and the vulcanization time was set at 170 ° C. for 15 minutes. The opening speed of the upper and lower dies 14, 15 after vulcanization molding is as follows:
It was set to 10 mm / sec.

In the first experimental example, a hexagon wrench is inserted into the hexagon locking groove 38 so that the spring force of the coil spring 36 has the characteristic shown by the solid line in FIG.
7 was adjusted by turning. That is,
The initial load by the push pin 35 was set to zero.

In Experimental Example 2, the adjusting nut 37 was advanced by 1 mm by the above-described adjustment method, the spring characteristic was set as shown by the two-dot chain line in FIG. 5, and the initial load by the push pin 35 was set to 68 kgf. Therefore, an initial pressure of 21.7 kgf / cm ² in terms of the cylindrical cross-sectional area of the unvulcanized rubber 24 in the seamless pipe 11 was applied.

In Experimental Example 3, the adjusting nut 37 was advanced by 4.8 mm to set the spring characteristics as shown by the broken line in FIG. 5, and the initial load by the push pin 35 was set to 313 kgf. Therefore, an initial pressure of 100 kgf / cm ² in terms of the cylindrical cross-sectional area of the unvulcanized rubber 24 was applied.

In the experimental example 4, the initial load of the push pin 35 by the coil spring 36 having the spring constant of 90 kgf / mm was set to 900 kgf by adjusting the adjust nut 37, and the spring characteristic was set as shown by the one-dot chain line in FIG. did. Therefore,
290 kgf / cm ² in terms of cylindrical cross-sectional area of unvulcanized rubber 24
This means that the initial pressure was applied.

Further, an experiment was conducted under the same conditions as described above using the above-mentioned conventional apparatus.

The results of such an experiment will be described with reference to Table 1.

[0037]

[Table 1]

The rubber roller molded products obtained in Experimental Examples 2 and 3 in which the initial pressure was applied had no problem in appearance, the rubber near the injection hole 22b was also firmly attached to the roller body, and the end surface was finished. Was also good. On the other hand, in the rubber roller molded products of Experimental Examples 1 and 4, burrs were generated on the end surfaces, and there was a defect of the rubber near the injection hole 22b, which was slightly inferior. However, there was no problem in the quality of the molded products themselves. This is because the excessive internal pressure of the cavity 16 is
This is because the spring force of No. 6 effectively absorbed the water.

On the other hand, in the case of using the conventional apparatus, as is apparent from the comparative example in Table 1, as described above, the rubber near the injection hole is scattered and the roller body is not slid. Phenomena such as peeling of rubber occurred.

When opening the mold, first, the upper mold 1
4 is raised upward at the above-mentioned predetermined speed.
The slide core 39 pressed by c gradually moves to the left in FIG. 2 while being held by the spring force of the coil spring 36 via the inclined outer end surface 39a, and is held at the dashed line position. Therefore, when the mold opening is completed, the pressure of the seamless pipe 11 is reduced to a free state, and no pressure acts. Therefore, it was possible to easily take it out of the lower mold 15 without using a tool such as a crowbar as in the related art. In order to take out the rubber roller from the seamless pipe 11, the difference in the contraction rate of the rubber may be utilized by cooling the seamless pipe 11. Further, in the conventional apparatus, the seamless pipe has to be taken out with a bar or the like as described above.

Thus, as is apparent from each of the experimental examples, the initial load of the coil spring 36 is adjusted in the range of 0 to 900 kgf, that is, 0 to 29 kgf per roller cylinder cross-sectional area.
An excellent molded product can be formed by receiving the internal pressure of the cavity 16 of 0 kgf / cm ² . Desirably, if the initial load of the coil spring 36 is set to ²⁰ to 100 kgf / cm ² per roller cylindrical cross-sectional area, more excellent effects can be obtained.

The rubber volume of the rubber roller, the vulcanization temperature,
There is an optimum range between the cavity pressure behavior due to the rubber compound material, the accompanying mold structure, etc., and the spring force of the coil spring, which is not limited to the numerical value (kgf / cm ² ) in this experimental example. Absent.

The range of use is expanded by arbitrarily changing the spring force of the coil spring 36 with the adjustment nut 37. Furthermore, upper and lower molds 1 which are vulcanization molds
By incorporating the spring absorbing means 17 into the upper and lower dies 14, 15, it is understood that it is sufficient to provide a heat source to the two dies 14, 15 instead of applying pressure.
Can be sufficiently reduced in pressure as compared with the conventional press.

The spring absorbing means 17 is not limited to the coil spring 36 but may be changed to a disc spring or the like.

[0045]

As is apparent from the above description, according to the partingless roller manufacturing apparatus of the present invention, the productivity can be improved by the high-temperature vulcanization molding.
The spring absorbing means effectively absorbs the excessive expansion internal pressure of the cavity during vulcanization molding, thereby preventing the occurrence of defective products and reducing the pressure of the seamless pipe from the mold after release from the mold. It becomes extremely easy, and the work efficiency can be improved and the cost can be reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing one embodiment of a manufacturing apparatus of the present invention.

FIG. 2 is a longitudinal sectional view showing the operation of the present embodiment.

FIG. 3 is a longitudinal sectional view showing a seamless pipe provided in the present embodiment.

FIG. 4 is a sectional view of an essential part showing an injection machine for injecting unvulcanized rubber into the seamless pipe.

FIG. 5 is a characteristic diagram showing spring force and displacement of a coil spring in each embodiment.

FIG. 6 is a longitudinal sectional view showing a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 ... Seamless pipe 12, 13 ... Core metal holding member 14 ... Upper mold 15 ... Lower mold 16 ... Cavity 17 ... Spring absorption means 18 ... Decompression means 19 ... Variable means

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI G03G 15/10 112 G03G 15/10 112 15/16 103 15/16 103 15/20 103 15/20 103 // B29K 21:00 105: 20 105: 24 B29L 31:32. 330 oni Inugawa Rubber Industries Co., Ltd. (58) Field surveyed (Int.Cl. ⁶ , DB name) B29C 39/00-39/44 B29C 35/00-35/18 B65H 5/06 F16C 13/00 G03G 15/10 112 G03G 15/16 103 G03G 15/20 103

Claims (2)

(57) [Claims] 1. A seamless pipe mounted in a cavity between split molds for vulcanization molding, and vulcanization of unvulcanized rubber provided at one end of the seamless pipe and filled inside the seamless pipe. A spring absorbing means for absorbing the internal pressure of expansion of the cavity at the time of sulfur molding, and a spring absorbing means provided at the other end of the seamless pipe, the internal pressure of the cavity and the spring force of the spring absorbing means when the split mold is opened. A parting-less roller manufacturing apparatus, comprising: a pressure reducing means for gradually reducing a balance pressure. 2. The partingless roller manufacturing apparatus according to claim 1, further comprising a variable means for changing a spring force of said spring absorbing means.