JPH0455846B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an injection molding machine equipped with a colorant supply device, and particularly to an injection molding machine equipped with a cleaning agent supply device.

(Prior art) Conventionally, in an injection molding machine equipped with a colorant supply device, the colorant is dropped from the raw material hopper into the molding raw material, and in the case of liquid colorant, the colorant is dropped into the raw material hopper or the raw material input port of the raw material feed device. It is supplied by drip or spray. When changing the color, the heating cylinder and screw are cleaned by supplying the raw material of the liquid cleaning agent instead of this coloring agent. However, when the coloring agent is supplied at the same time as the raw material is supplied, the raw material in this part is not yet melted, so the coloring agent tends to adhere to the inner surface of the heating cylinder and the screw in this part, making them dirty. . Regarding the cleaning agent, if the cleaning agent is supplied at the same time as the raw material, the cleaning agent will adhere to the surface of the raw material, making the raw material slippery and making it difficult to feed the raw material uniformly inside the heating cylinder. However, since the raw material is unmelted and bulky, color stains adhering to the screw and the inner surface of the heating cylinder cannot be effectively removed, and as a result, the color cannot be changed efficiently. .

By the way, the applicant previously proposed in Japanese Patent Publication No. 59-1187 that when a coloring agent is supplied in the front part of the feed zone close to the compression zone of the screw in the heating cylinder, since the raw material is in a molten state, the inner surface of the heating cylinder is It has been disclosed that pigments are difficult to adhere to and can be effectively mixed with colorants.

However, if the cleaning agent is supplied by the same supply device as the colorant, the supply device itself must be cleaned.

(Problems to be Solved by the Invention) In the above situation, the present invention provides an independent cleaning agent supplying device in addition to the coloring agent supplying device to effectively supply the cleaning agent at the time of color change. An object of the present invention is to provide an injection molding machine equipped with a new colorant supply device, which prevents pigment from adhering to the inner surface of a heating cylinder or screw, has an excellent cleaning effect, and can quickly change colors. It is.

(Means for Solving the Problems) That is, the present invention provides a colorant supply method in which a liquid pigment is press-fitted into the heating cylinder of an injection molding machine at the front of the feed zone adjacent to the compression zone of the screw. The present invention relates to an injection molding machine with a colorant supply device, characterized in that it is provided with a cleaning agent supply device for press-fitting a device and a liquid cleaning agent.

(Function) By providing a colorant supply device for press-fitting a liquid pigment and a detergent supply device for press-fitting a liquid detergent at the front of the feed zone near the compression zone of the screw in the heating cylinder of the injection molding machine, the First, since the colorant is supplied close to the compression zone where the raw material is melting, the colorant is mixed into the molten raw material smoothly, and the colorant does not adhere to the inner surface of the heating cylinder or the surface of the screw. It is hard to clean and therefore hard to get dirty. Secondly, based on the same principle, the cleaning agent supplied close to the compression zone is easily mixed into the molten raw material, making it possible to clean the inner surface of the heating cylinder and the surface of the screw as the raw material advances. can.

(Example) An example will be described below according to the attached drawings. Figure 1 is a cutaway sectional view showing an example of an injection molding machine with a colorant supply device, and Figure 2 is a heating cylinder cut in the circumferential direction. FIG. 3 is an enlarged sectional view of the main parts showing an embodiment showing details of the raw material supply device.

Figure 1 shows an injection molding machine 10 with a colorant supply device.
is illustrated in its entirety. That is, in the figure, the heating cylinder 11 in which the screw 12 is installed is attached to the injection table 1 on the slide base 16 of the machine stand 15 at the rear thereof.
7 so that it can reciprocate. Reference numeral 13 represents an injection cylinder that advances the screw 12 and injects the molten raw material from the tip of the cylinder, and reference numeral 14 represents a motor that rotates the screw 12. Reference numeral 19 is a band heater wrapped around the heating tube 11, and 20 is a raw material hopper.

The screw 12 fitted into the heating cylinder 11 is composed of a metering zone M, a compression zone C, and a feeder zone F from its tip side.

In this invention, the coloring agent supply device and the cleaning agent supply device are provided in front of the feed zone F in the heating cylinder 11, which is close to the compression zone C of the screw 12. In FIG. 1, only the colorant supply device 30 is shown because of the cross-sectional view taken in the cylindrical direction of the heating cylinder 11. FIG. 2 is a sectional view taken in the circumferential direction of the heating cylinder 11 at the colorant supply device 30 portion, and as shown in this figure, in the embodiment, three colorant supply devices 30, 31, 3
2 and a cleaning agent supply device 40 are arranged radially around the outer periphery of the heating cylinder 11.

The colorant supply devices 30, 31, 32 and the cleaning agent supply device 40 of the embodiment all have a common press-fit valve structure. To explain the valve structure using the colorant supply device 30 as an example, a valve stem 52 that is always urged forward by a rear spring body 55 is inside a valve body 51 attached to the outer peripheral surface of the heating cylinder 11. It is inserted. When the liquid is forced into the valve from the inlet 58 at a pressure higher than the spring pressure of the spring body 55, the injection pressure moves the valve stem 51 backward, and the conical valve at the front end of the valve stem moves. The portion 53 opens and liquid is supplied into the heating cylinder 11 from the supply port 59. With a valve having such a check valve structure, it is possible to prevent the raw material from flowing back from inside the heating cylinder when the supply of liquid is stopped.
Note that the colorant supply devices 31, 32 and the cleaning agent supply device 40 have exactly the same valve structure, so in FIG. Instead of that explanation.

FIG. 3 shows a colorant supply device 30, (31, 32).
and a pumping device for the cleaning agent supply device 40 are shown. Needless to say, this pressure feeding device 60 is provided independently for each of the colorant supply devices 30, 31, 32 and the cleaning agent supply device 40. As shown, the liquid coloring agent or the liquid cleaning agent in the liquid tank 61 is pumped by a pressure pump 62 to a supply device, respectively. Each liquid is pumped at an arbitrary pressure (usually 10 to 150 kg/cm ² ) so as to overcome the resin pressure within the heating cylinder 11 . A control valve 64 which also serves as a stop valve is provided in the middle of the conduit 63 to control the flow rate of the liquid. Reference numeral 65 is a pressure gauge that monitors the pressure of liquid injection.

(Operation) Next, the operation of this invention device will be explained according to the diagram in FIG.

First, the feed screw 22 of the raw material feed device 21 rotates at the same time as the screw 12 rotates.
The raw material P in the raw material hopper 20 is fed into the heating cylinder 11 from the raw material input port 25. The feed amount of the raw material P changes and is adjusted depending on the rotational speed of the motor 23 of the feed screw 22.

At a position near the compression zone C in front of the feed zone F of the raw material input port 25,
Three colorant supply devices 3 as shown in FIG.
0, 31, 32 and a cleaning agent supply device 40 are arranged. In the embodiment, three colorant supply devices 30, 31, and 32 are provided with liquid colors of red, blue, and yellow, respectively, and are supplied selectively or in a mixed state as needed.

Note that the shade of the color tone can be appropriately controlled by the liquid injection pressure of the above-mentioned liquid pumping device and by the amount of raw material fed into the raw material feed device 21.

When changing the color, the supply of colorant by the colorant supply devices 30, 31, and 32 is stopped, and the liquid detergent is supplied into the heating cylinder 11 by the detergent supply device 40. The liquid cleaning agent supplied into the heating cylinder 11 is mixed with the raw material that is being melted and moves forward inside the cylinder while being kneaded, thereby cleaning the inner surface of the heating cylinder 11 and the screw 12.

In addition, in the apparatus of this invention, since the cleaning agent is pumped by the press-in device, a high viscosity liquid cleaning agent can be used, and fine particulate additives such as tankar can be mixed therein. By mixing fine particles and additives, it becomes possible to mechanically squeeze and forcibly discharge the resin remaining in the heating cylinder and screw.

(Effects) As shown and explained above, in the device of the present invention, the coloring agent supply device for press-fitting the liquid pigment and the cleaning agent supply device for press-fitting the liquid detergent are connected to the screw compressor in the heating cylinder of the injection molding machine. Since it is installed at the front of the feed zone near the tension zone, first of all, the coloring agent can be mixed into the molten raw material smoothly, and the coloring agent is less likely to adhere to the inner surface of the heating cylinder or the surface of the screw. Therefore, it is hard to get dirty. At the same time, based on the same principle, the cleaning agent supplied near the compression zone is easily mixed into the raw material, so that the inner surface of the heating cylinder and the surface of the screw can be thoroughly cleaned as the molten raw material moves. . In this way, the device of this invention has two functions: supplying a coloring agent that is hard to stain and supplying a cleaning agent that is easy to remove stains, so it is possible to perform this type of color change extremely efficiently. It became like that. In addition,
According to a comparative experiment conducted by the applicant, the conventional device required at least 20 shots to change the color, but the device of the present invention was able to completely change the color in half, 10 shots.

[Brief explanation of the drawing]

Figure 1 is a cutaway sectional view showing an example of an injection molding machine with a colorant supply device, Figure 2 is an enlarged sectional view of the main part of the heating cylinder cut in the circumferential direction, and Figure 3 shows details of the raw material supply device. FIG. 2 is an enlarged cross-sectional view of essential parts of the illustrated embodiment. 10... Injection molding machine, 11... Heating cylinder, 12...
...Screw, 20...Raw material hopper, 21...Raw material feed device, 25...Raw material input port, 30,3
1, 32...Coloring agent supply device, 40...Cleaning agent supply device, 51...Valve body, 52...Valve stem, 5
5... Spring body, 60... Pressure feeding device, 61... Tank, 62... Pump, M... Metering zone, C... Compression zone, F... Feed zone, P... Raw material.

Claims (1)

[Scope of Claims] 1. A colorant supply device that presses a liquid pigment into the heating cylinder of an injection molding machine and a cleaning device that presses a liquid detergent into the front part of the feed zone adjacent to the compression zone of the screw in the heating cylinder of the injection molding machine. An injection molding machine equipped with a colorant supply device, characterized in that it is provided with a colorant supply device. 2. An injection molding machine with a colorant supply device according to claim 1, wherein a plurality of colorant supply devices are installed. 3. An injection molding machine with a colorant supply device according to claim 1, wherein the colorant supply device and the cleaning agent supply device are installed radially with respect to the heating cylinder.