BE1013847A3 - PROCESS AND INSTALLATION FOR THE MANUFACTURE OF BRUSHES. - Google Patents

Abstract

Method and installation for the manufacture of brushes, in particular toothbrushes, in which brush bodies are produced by injection molding in an injection molding machine and are then or then fitted with bristle bundles, in which further , for the manufacture of optically different brush bodies or brushes, the injection material is transported from a storage tank through an injection assembly to the mold cavities and is supplied, in this path of transport, after the injection assembly in the direction of flow, by coloring, particles or similar additives which are optically active and / or in that additives are directly introduced into the molding cavities with the material to be injected .

Description

"Method and installation for manufacturing brushes" The invention relates to a method for manufacturing brushes, in particular toothbrushes, brush bodies being produced by injection molding in an injection molding machine and then being equipped or subsequently bundles of hair.

In addition, the invention relates to an installation for implementing the method.

Toothbrushes are produced in several colors, for example ten, with regard to the brush body. This could be done following the implementation of a corresponding number of injection molding machines; apart from the high cost, it is however also disadvantageous that due to the numbers of parts, which are different overall, of the brush bodies for the different colors, there would be no regular use of the machines. In practice, during the production of the brush body, color changes are made which are however minute and time consuming and which also cause a not insignificant drop in production.

Either the different dyes are dry mixed with the material, for the brush bodies, which is in the form of plastic granules, and this mixture is then heated in the screw and piston extruder or in a similar transport device , is fluidized and is then brought by distribution channels to the mold cavities or molding niches during the injection process, either however a fluid dye is used which is injected into the access chamber of the screw in the case a screw and piston extruder.

When changing color, any remaining dye should be flushed from the screw and piston extruder and the distribution channels. This is done; the new dye is introduced and brush bodies are injected therewith until the last remnants of the previous dye are rinsed. This can take up to an hour and the brush bodies produced then form unusable scraps because in addition to the new color, they also contain remnants of the old color. A control of the injection molding machine, which otherwise operates automatically, is also necessary for monitoring color change.

The cost for a color change is so high that it is carried out as little as possible in practice. Brush bodies of each color are produced in reserve for this reason. In the case of production of brush bodies of one color, which goes beyond the need, large quantities of brush bodies must however be temporarily stored so that brush bodies of all the intended colors are available in the desired color matching ratio then, for the next stuffing when producing brushes. For this purpose a need for space corresponding to a necessary. It is also problematic then that measures must be taken by which fouling of the brush bodies is avoided for a fairly long time. This is particularly true for hygienic reasons in the case of the production of toothbrush bodies.

In order to avoid temporary storage, the brush bodies produced could certainly be brought directly to the packing, but sorting by color, still expensive, would then be necessary after the packing or after packaging.

Regardless of whether brush bodies, or finished brushes, of different colors are temporarily stored, it is necessary to group brushes or brush bodies from different storage areas according to the desired color assortment. The positions of brushes or brush bodies transported, during supply, to further processing devices, in particular a tamping machine when supplying brush bodies, or to cutting, polishing and other devices further processing, must be checked and corrected in position if necessary, and this means a considerable additional expense. In particular in the case of brushes or brush bodies injected, made up of several components and which then have by area rubber-like sections on the external side, the position correction poses a problem and represents a significant source of failure.

The problem of the present invention is to provide a process by which production is possible corresponding to the number of pieces associated with the forecasts from the point of view of at least the color and of each color. The expense for a color change to be undertaken as needed must be significantly reduced. In addition, an installation for implementing the method must be carried out.

For the solution with regard to the method, it is proposed according to the invention that, for the manufacture of brush bodies or optically different brushes, the material to be injected is transported from a storage container, via 'an injection set, up to the mold cavities and, in this transport path after the injection set in the flow direction ^ is provided with dye, particles or additives of this kind optically active ingredients and / or additives are introduced directly into the molding cavities with the material to be injected.

If the additive is directly introduced into the molding cavity, is in particular injected, it is possible practically to change from injection cycle to injection cycle a color change or change to another embodiment of the brushes or brush body without being necessary there between flushing processes.

Without additional measures for the mixture of dye or other similar elements and of the material to be injected, targeted optical embodiments can also be undertaken in the case of a direct injection or of an injection of the additive near the respective mold cavity, the brush bodies possibly having no continuous color on a regular basis but a color sampling. The colored production can also vary simultaneously by adding several colors or other additives. Even when one does not inject directly into the mold cavities, the zone crossed by the previous color is appreciably smaller when a color change is necessary and thus a faster change is possible. At least the screw and piston extruder or similar conveying device is then separated from the area which has particular color, so that the material to be injected therein should not be rinsed out during a change of color. With each movement more towards the molding cavities of the place of supply of dye or of a similar element in the transport path of the material to be injected, the area crossed by the additive is reduced and thus the expense for the rinsing when changing color or otherwise changing the embodiment.

In the case of a tool usually having a plurality of molding cavities, brush bodies which are also different in color can be injected simultaneously, so that absolutely according to the need and the assortment of colors requested, the latter can already be properly composed in the injection molding machine.

The manufacture of optically different brushes or brush bodies is linked, by the manufacture according to the invention in an injection molding machine, to a comparatively low expense which corresponds approximately to that for the injection of identical brushes or brush bodies. If the assortment of colors or the color has to be changed when only one color is injected, this can be done in a very short time.

A development of the invention, for which independent protection is claimed, provides that, during injection molding, brush bodies or brushes are produced simultaneously in different embodiments, at least as regards color or color. optical appearance of this kind and / or shape and / or by covers by extrusion and in that the brush bodies or brushes are removed from the injection molding machine in a predetermined order and are brought, sorted in this order, to a tamping device and / or to a further processing or finishing device.

The brushes or brush bodies of different embodiments are thus available directly after injection and are transported further from the injection molding machine in a sorted shape that is correct in position. In order to be able to close the mold as quickly as possible after an injection process, removal of the finished brushes or brush bodies must be carried out quickly. In most cases, all brush bodies or brushes should be removed from the mold at once for this reason. If the color order is already taken into account in the injection molding machine, the brushes or brush bodies removed at once can be transported directly further, depending on the assortment removed.

However, there is also the possibility of removing brushes or brush bodies separately or in groups from the injection mold, this can be done one after the other in time or simultaneously, and then to assemble a desired series. of brushes or brush body for subsequent transport. Particularly economical manufacturing, for a simultaneously increased flow rate, is possible in connection with the sorted and correct subsequent transport in position of the brushes or brush body to a tamping machine or to subsequent processing machines.

It should also be mentioned that as an additive it is possible to add, on one side, the dye, in particular fluid dye, but where appropriate also additives in the form of granules or paste or, however, others, by example in the form of particles, in order to obtain optically different effects. For example, synthetic material or metallic flakes which cause a flickering effect can be added as an additive in combination with colorant or even separately.

In the case of a plurality of molding cavities provided in an injection tool, these are connected in groups by a main channel distributor or by several auxiliary channel distributors, to the device for transporting material to be injected. Then, according to one embodiment of the invention, there is the possibility of introducing dye or an additive of the same kind at least both in an auxiliary channel distributor and also in a main channel distributor of an arrangement. distribution channels.

If the additive is brought to the main distributor, all the mold cavities of the connected tool are supplied with, for example, material to be injected of the same color. When the dye or the like is supplied to one or more auxiliary distributors, optically different brush bodies can be produced in the injection molding tool in groups.

In addition, there is the possibility of introducing dye or a similar element into a nozzle connected to a molding cavity.

If the dye or an additive of this kind is supplied directly to one or more auxiliary distributors, to one or more nozzles or to the mold cavities, depending on the number of mold cavities or groups of mold cavities present, and also in function of the number of optically different embodiments desired, for example colors, a color change is still only necessary for very large variations in time and even, under certain circumstances, after all, no color change is no longer necessary, so that the problems which are connected with it no longer appear either only or only to an absolutely reduced extent.

According to a development of the invention, it is provided that additive, for example dye, is added in a metered manner to the material to be injected. By adding different amounts of the additive, the mixing ratio with, for example, white material for injection can be changed and different shades in one color can also be obtained.

Appropriately, the supply of the additive is blocked during the pressure maintenance phase, during the injection process. As a result, the additive supply system can operate with a comparatively reduced pressure, which should be barely higher than the pressure in the transport path of the material to be injected during feeding to the molding cavities and before the pressure maintenance phase.

The invention also relates to an installation for implementing the method according to the invention. This installation is characterized by the fact that, for optically different injected objects, the injection molding machine which has an injection molding tool comprising an injection molding mold and an injection assembly comprises distribution channels which lead from the injection assembly to the separate molding cavities, one or more lines for dye, particles or additives of this type acting optically being connected to said channels and / or to the cavities.

The significant advantages obtained with this installation are already described previously by means of the method according to the invention. In a particular way, by these measures, particular color changes are linked to a significantly lower cost and can be carried out more quickly. In the case of injection molding tools, comprising several groups of molding cavities, as is usual in the case of the manufacture of small brush bodies or brushes, in particular toothbrush bodies, brush bodies different, for example different colors, can be made simultaneously and a color change is even superfluous in the case of a number of mold cavities or groups of mold cavities corresponding to the desired colors or the like of the brush bodies .

It is advantageous that the supply channel has, behind the outlet orifice, in the direction of flow, of a pipe for additives at least one mixing device, preferably a mixing chamber formed by an enlargement of cross section.

For a good mixture of the colorant and / or other additives and of the basic material to be injected, it is certainly generally sufficient that there is a path between the additive supply location and the molding cavity. specified transport in which mixing takes place during transport. However, a good mixture can be obtained by the use of one or more mixing devices, also in the case of additions of the additive near the molding cavity. A mixing chamber formed by an enlargement of the cross section has the advantage that there is a simple construction and that no disturbance can occur.

In order to improve the mixing of the additive and the material to be injected, the orifice of the additive pipe can be made in the form of an annular nozzle near the supply channel. Therefore, the additive simultaneously penetrates several places distributed peripherally in the supply channel with the material to be injected, so that in this case there is already an intense mixture. In particular in combination with one or more successive mixing devices, for example a mixing chamber, a good mixture of material to be injected and additives can be obtained.

A development of the invention for which independent protection is claimed, provides that an injection molding machine is produced for the simultaneous injection of objects to be injected in different embodiments, at least as regards color. and / or the shape and / or covers by extrusion and to the injection molding machine is added a removal device which can be programmed for the removal of brush body or toothbrushes in a predetermined order.

The injected objects are thus available, in a directly sorted manner after the injection according to a determined order and can be supplied according to this order to processing machines. Even for further processing, for example stuffing, cutting, polishing, packaging, the order is kept, so that no additional device for recognizing the embodiment and position of the objects injected is no longer necessary.

The withdrawal device is made, or can be programmed, suitably with withdrawal pliers for the selective simultaneous entry of all the injected objects or for the entry in groups or separately of the finished injected objects.

If the position of the brushes or brush body in the mold already corresponds to the order provided for further processing, all the objects injected can be removed simultaneously in this position and be transported further. The planned order can however also be composed during the withdrawal; the pliers deposit in the appropriate place, in the order to be produced, the objects injected each time seized. In this case, it is necessary that the removal device has several removal clips which can be positioned independently of one another.

These are then preferably part of a handling device or a handling robot.

According to a development, it is intended that the removal device is installed after the transport device which preferably has a conveyor belt and that the removal device can be programmed for depositing brush bodies or toothbrushes on the belt conveyor or the like, sorted in a predetermined order.

The brushes or brush bodies deposited in a sorted manner are brought using the transport device to a tamping machine and / or to subsequent treatment or finishing devices, the predetermined order of the brush bodies or toothbrushes being kept during this treatment.

Other details and particularities of the invention will emerge from the secondary claims and from the description of the drawings which are annexed to the present specification and which illustrate, by way of non-limiting examples, the process and particular embodiments of the installation. according to the invention.

It is shown somewhat schematically: in FIG. 1, a side view, presented in section, of an injection molding tool comprising an injection assembly, in FIG. 2, an injection assembly comprising an arrangement of distribution channels connected as well as dye lines connected in the area of the auxiliary distributors, in Figure 3, an arrangement somewhat comparable to that shown in Figure 2 but with a dye line near the nozzles in this case, to FIG. 4, an arrangement of distribution channels with a dye line in the case of a main distributor, in FIG. 5, an arrangement of distribution channels comprising a dye line in the orifice area of a connected nozzle to a molding cavity, and in FIG. 6, an injection molding machine comprising a withdrawal device for injected objects, a transport device as well as a bour machine rage.

In the various figures, the same reference notations designate identical or analogous elements.

From an injection molding machine, we can see in Figure 1 the injection molding tool 1 and the injection assembly 2 which is connected to it. With the aid of the injection assembly which has a transport device, preferably in the form of a screw and piston extruder, as well as a line of material to be injected 3, fluidized material to be injected is brought by an arrangement of distribution channels 4 to molding cavities 5. The supply is made, in the present case according to FIG. 1, via a main distributor 6 from which nozzles 7 lead to the cavities 5 separate molding. Usually, for the manufacture of toothbrush bodies, there are provided tools with heating channels for which the mass to be injected contained in the supply or distribution channels is kept at an injection temperature. The nozzles 7 are also then produced in the form of so-called heating channel nozzles and they are provided with a heating means.

In the case of the embodiment shown in FIG. 1, it is brought into the main distributor 6 of the dye 8 by means of which the material to be injected which comes from the injection assembly 2 is colored for the manufacture of bodies. of colorful brush. As already mentioned previously, the addition of dye to the main distributor 6 and there into the main feed channel 9 is carried out before branching to the separate nozzles 7. The material to be injected transported in the direction of the arrow Pf1 from the injection assembly 2 mixes with the dye which, coming from the dye line 10, enters the main supply channel 9, a sufficient mixture material to be injected being made in the additional transport path to the mold cavities. It is of considerable importance for this purpose that the dye is not already brought into the area of the injection assembly, so that, when a color change is necessary, only the section of channel which is connected in downstream behind the dye arrivals 10 contains colored masses to be injected which must be injected and rinsed when the color changes. As the supply of the dye is carried out only in the main supply channel 9, the volume of channel to be rinsed is substantially reduced. The dye line 10 which opens near one of the channels of a distribution channel arrangement 4 comprises a supply line 11, a pump 12 and a storage container 13 for the dye. The pump 12 is preferably made in the form of a feed and metering pump, so that predetermined mixtures of dye can be mixed with the material to be injected.

At the outlet of the dye line 10 in a channel of the distribution channel arrangement 4, for example the main supply channel 9, a stop slide 15 can be provided (see FIG. 4 ) which is not shown in FIG. 1 or a similar valve so that the supply of dye can be cut off during the pressure maintenance phase which operates at high pressure. Therefore, an entry of material to be injected, from the arrangement of distribution channels 4, into the dye line 10 is avoided. In the simplest case, a check valve can be provided for this purpose so that, in the case of a higher pressure in the arrangement of distribution channels compared to that in the dye line 10 , the dye supply is closed. The stop slide or similar element can also be produced in the form of a metering valve by means of which a metered distribution of fluid dye is possible.

In addition to continuous dosing, the dye can also be added intermittently, so that brush bodies can be produced with corresponding color sampling.

It should also be mentioned that the dye is brought to a temperature approximately equal to that of the material to be injected, so that adverse reciprocal influences of the two materials are avoided. For this purpose, a separate temperature balancing device can be provided for the dye, or however the heating device for the heating channel supply is also used simultaneously in order to bring the dye to a corresponding temperature.

FIG. 2 shows an arrangement of distribution channels 4a for which the main distributor 6 is connected to an auxiliary channel distributor 14. In FIG. 2, two auxiliary distributors 14 are connected to the main distributor 6 but, offset in parallel in the drawing plane, even more auxiliary distributors, for example in four planes with each two auxiliary distributors, could also be connected to sixteen mold cavities 5. As can be seen in FIG. 2, the dye lines 10 in this embodiment is connected, for each auxiliary distributor 14, to the channel 16 coming from the main distributor 6, so that each time two brush bodies of the same color can be injected. In an embodiment carrying a total of sixteen molding cavities 5, this would mean that, by injection blow, sixteen brush bodies of eight different colors can be produced simultaneously.

The supply of dye to the arrangement of distribution channels 4 is carried out in FIG. 4, in the case of the main distributor 6, at the same location as that shown in FIG. 1, in the main supply channel 9. A For this purpose, however, two dye supply lines 10 are provided through which alternately different dye can be supplied. For this purpose, the outlet orifices of the dye supply lines 10 can be closed and opened alternately using a stop slide 15.

For intimate mixing of the dye, it is appropriate to provide one or more mixing devices in the supply path, in particular when the dye line 10 is located near the molding cavity 5.

Figure 4 shows mixing chambers 17 which are arranged in the secondary channels 16 derived from the main supply channel 9 and which are formed by cross-sectional enlargements. Such cross-sectional enlargements result in the flowing material to be injected and is thus better mixed with the added dye.

Instead of these particularly simple but effective mixing devices, other mixing devices, for example a gear pump, if necessary without drive, or the like could be provided.

As another measure for a good mixture of the material to be injected and the supplied dye, the orifice of the dye line 10 can be produced in the form of an annular nozzle near the distribution or supply channel. An annular nozzle of this kind may also have, in a distributed manner around the periphery, several outlet orifices, so that, during the supply, the dye is already introduced, in the flow of material to be injected, in a distributed manner over the cross section of it, so that there is already a good mixture on a very short path.

Figure 3 shows an arrangement of distribution channels 4a corresponding approximately to that of Figure 2, the dye lines 10 leading to each heating channel nozzle 7. Therefore, in each molding cavity 5 (see Figure 1) associated with a nozzle 7, a brush body can be injected with the possibility of choice i as regards the color. In this case also measures for a better mixture of the material to be injected and the dye can be provided still in the remaining path to the molding cavities 5.

In the case of the arrangement shown in FIG. 5, the supply of dye is carried out near the end, on the side of the molding cavity, of the heating channel nozzle 7, and thus directly in the molding cavity 5. In this exemplary embodiment, the supply of dye is carried out coaxially in the nozzle channel and in this case a needle-closing nozzle 18 is provided in this case for a metered supply of dye. Admittedly, in the case of a direct injection of dye into the cavity 5, no homogeneous mixture of dye is possible; brush bodies can however be colored in this way, with mixed colors or striated areas occurring. Brush bodies with several colored areas can also be produced by intermittent supply.

A colored shaping of this kind can also be carried out, in the case of a dye line distant from the inlet of material to be injected near the molding cavities 5, when the distance from the outlet orifice of a colorant line with respect to the molding cavity which is connected to it is tuned to the volume of the element to be injected and the range of colors provided. Areas of colored areas in a brush body can also be produced in this way by intermittent supply of dye.

It should also be mentioned that the material to be injected itself, supplied through the injection assembly 2, may already have a basic color, for example white, so that mixed colors can also be produced with the dyes, preferably fluids, introduced as a supplement. Usually, for the base material to be injected, however, it is a colorless, mainly transparent material.

The dye can be brought in a different shape, depending on the position of the dye line in the transport path of the material to be injected. In particular, in the case of direct addition to a molding cavity, it is appropriate to add the dye in the form of a fluid dye while in the case of addition of the dye at a distance from a molding cavity, there is also the possibility of bringing dye or other additive in another form, for example, in another pasty form or as a granule because, in the subsequent transport path, then there remains still sufficient time for a good mixture or for a fusion of the additive.

In the embodiment according to FIGS. 1 to 5, the invention has been described in connection with dye as an additive, in order to be able to make brushes or brush bodies different in color. However, there is also the possibility of providing as additives, instead of or in combination with different dyes, other substances by which the optical appearance can be modified. There is thus the possibility of adding as an additive particles by which a flickering effect can be produced. An additive of this kind can be formed for example by fine flakes of synthetic material or metal. Even powder additives can be added to achieve specific effects.

In addition, there is the possibility of developing the injection molding tool 1 so that brushes or brush bodies which differ in shape and / or with respect to injection covers can be produced. also simultaneously in the mold. Thus, both brushes or brush bodies shaped optically differently than also injected objects different from the point of view of their external appearance can be produced in an injection molding machine.

FIG. 6 shows a plan view of a "complete installation" which, in the embodiment example, includes an injection molding machine 19, an injection casting mold 20, a withdrawal robot 21, a transport device 23 formed by a conveyor belt 22 and a tamping machine 24. If necessary, a packaging machine not shown in this case, belonging to the complete installation, can be connected to the tamping machine 24.

The injection molding machine 19 is produced, as described with the aid of FIGS. 1 to 5, for the manufacture of optically different injected objects, in particular by color, of the brush bodies 25 in the present embodiment.

The finished brush bodies are gripped in the open injection mold 20 using at least one removal gripper 26, they are transported by the removal robot 21 to the conveyor belt 22 and they are deposited there in a predetermined order. On a gantry 27, of the withdrawal robot 21, which can be moved along a double arrow Pf2, the withdrawal clamp is arranged so as to be able to rotate and pivot as well as, preferably, also so as to be transversely movable relative to the direction for moving the gantry 27. Either the withdrawal clamp 26 can be made for the simultaneous entry of all the injected objects; on the other hand, several withdrawal clips which can be positioned independently of one another can also be provided.

If the order of the brush bodies 25 to be deposited on the conveyor belt 22 also corresponds to the position in the injection mold 20, when removing from the injection mold 20 open the brush bodies 25 can be taken up maintaining their relative position with respect to each other and being deposited on the conveyor belt 22. If this is not so, the finished brush bodies 25 can also be removed by group from the mold, one after the other the other by a withdrawal clamp 26 or simultaneously by several withdrawal clamps and be deposited on the conveyor belt 22 in accordance with the intended sorting.

With the aid of the removal robot 21, the removed brush bodies 25 can also be deposited at intervals, offset from one another, on the conveyor belt and, during the following removal process, the intervals are then filled with brush bodies of other colors, in accordance with the color assortment provided, so that the order provided for the brush bodies different by color is finally obtained.

According to the predetermined or compound sorting, the brush bodies 25 are brought to the tamping machine 24. He mentioned for this purpose that the brush bodies 25, during the transfer from the injection mold 20 to transport device, are deposited on the conveyor belt 22, both in a sorted manner with regard to the predetermined order and also in the same position, that is to say in the correct position for further processing, so that '' no position control and position correction are necessary in the subsequent course of transport.

The order of the colors on the conveyor belt 22 is also retained after the bundling of the bristle bundles 28 and the brushes are then brought in this order to subsequent treatment or finishing devices and finally also to a packaging machine. If there are rejects in the complete treatment, the corresponding brush bodies or the brushes can be replaced without problem, so that the planned order is kept.

It should also be mentioned that, when using an injection molding machine for the manufacture of brushes with injected bristles, the tamping machine 24 would be eliminated, so that, if necessary, further processing and a packaging machine can be connected to the transport device 23. In the case of an injection molding machine of this kind for the so-called INMOLD process, combinations of colors, bristles and of the brush body can be taken into consideration when matching colors. Thus, brushes and brush bodies can be produced either in the same color or, where appropriate, also in a manner which differs by color.

It should be understood that the invention is in no way limited to the embodiments described and that many modifications can be made to these without departing from the scope of the claims.

Thus, the injection molding machine can be made in the form of a one-component injection molding machine or also in the form of a multi-component; in the latter case, first a base body and then injections of the base body are injected.

In total, the present invention provides a highly flexible installation from the point of view of the most different embodiments of brushes and which allows, with low cost and also very quickly to switch to different data with regard to the assortment of brushes and also the separate embodiments.

Claims (28)

1. Method for the manufacture of brushes, in particular toothbrushes, in which brush bodies (25) are produced by injection molding in an injection molding machine (19) and are then or then fitted with beams bristles (28), characterized in that, for the production of optically different brush bodies (25) or brushes, injection material is transported from a storage tank (3) through a set of injection (2) to the mold cavities (5) and is supplied, in this transport path, after the injection assembly (2) according to the direction of flow, by dye (8), in particles or in similar additives which are optically active and / or in which additives are directly introduced into the molding cavities (5) with the material to be injected. 2. Method according to claim 1, characterized in that, during injection molding, brush bodies (25) or brushes of different embodiments, at least as regards color or such an optical appearance and / or the shape and / or by injection covers, are produced simultaneously and in that the brush bodies (25) or brushes are removed from the injection molding machine (19) in a predetermined order and are brought , sorted in this order to a tamping device and / or to a further processing or finishing device. 3. Method according to claim 1 or 2, characterized in that the brush bodies (25) or brushes removed from the injection mold (20) in the predetermined order are deposited in this predetermined order and in the same position on a transport device (23). 4. Method according to one of claims 1 to 3, characterized in that additive (8) is introduced into at least one auxiliary channel distributor (14) and / or a main channel distributor of an arrangement of distribution channels (4). 5. Method according to one of claims 1 to 4, characterized in that additive (8) is introduced at several places in the arrangement of distribution channels (4). 6. Method according to one of claims 1 to 5, characterized in that additive (8) is introduced into a nozzle (7) connected to a mold cavity (5). 7. Method according to one of claims 1 to 6, characterized in that the additive (8) is added in a metered manner to the material to be injected. 8. Method according to one of claims 1 to 7, characterized in that the supply of the additive (8) is blocked during the pressure maintenance phase during the injection process. 9. Method according to one of claims 1 to 8, characterized in that the additive (8) is added to the material to be injected at a temperature approximately equal to that of the material to be injected. 10. Installation for the manufacture of brushes, in particular toothbrushes or of injected objects of this kind, which has an injection molding machine (19), a transport device (23) for brush bodies (25 ) or toothbrushes, if necessary a tamping machine (24) as well as subsequent treatment or finishing devices, for implementing the method according to one of claims 1 to 9, characterized in that, for optically different objects, the injection molding machine (19), which has an injection molding tool (1) comprising an injection casting mold (20) and an injection assembly (2), comprises distribution channels which lead from the injection assembly (2) to the separate mold cavities (5) and in that one or more lines for dye (8), particles or additives of this kind optically active are connected to these channels and / or molding cavities (5). 11. Installation, in particular according to claim 10, characterized in that an injection molding machine (19) is produced for the simultaneous injection of injected objects, of different embodiments at least as regards color and / or the shape and / or covers by injection and in that the injection molding machine (19) is added a removal device which can be programmed for the removal of brush body (25) or toothbrushes according to a predetermined order. 12. Installation according to claim 10 or 11, characterized in that the withdrawal device comprises a withdrawal clamp (26) which is produced or which can be programmed for the simultaneous selective entry of all the objects injected or for the entry of injected objects completed by group or separately. 13. Installation according to one of claims 10 to 12, characterized in that the withdrawal device has several withdrawal clamps (26) which can be positioned independently of one another. 14. Installation according to one of claims 10 to 13, characterized in that after the removal device is installed the transport device (23) which preferably has a conveyor belt (22) and in that the removal device can be programmed to deposit, in a sorted manner in a predetermined order, brush bodies (25) or toothbrushes on the conveyor belt (22) or on a similar element. 15. Installation according to one of claims 10 to 14, characterized in that after the transport device (23) are installed the tamping machine (24) and / or the devices for further processing or finishing and in that the predetermined order of the brush bodies (25) or toothbrushes is retained during this treatment. 16. Installation according to one of claims 10 to 15, characterized in that pipes for additive (8) are connected to an auxiliary channel distributor (14) and / or to a main channel distributor (6) . 17. Installation according to one of claims 10 to 16, characterized in that an additive pipe (10) is provided near the outlet of a nozzle (7) which opens into a molding cavity and in that 'For this purpose, the pipe is preferably brought coaxially into the nozzle channel and opens at the outlet end of the nozzle. 18. Installation according to one of claims 10 to 17, characterized in that the lines (10) for additive (8) can be closed, preferably by means of stop slides (15). 19. Installation according to one of claims 10 to 18, characterized in that the stop slide (15) is produced in the form of a metering valve for the additive (8). 20. Installation according to one of claims 10 to 19, characterized in that the supply channel has behind the outlet orifice, in the direction of flow, of an additive pipe (10) at least one mixing device, preferably a mixing chamber (17) formed by an enlargement of cross section. 21. Installation according to one of claims 10 to 20, characterized in that, in a distribution channel, the distance between the outlet orifice of an additive pipe (10) and the mold cavity which s connection is granted to the volume of the object to be injected and to the optically modified zone provided, in particular a colored zone in a brush body (25). 22. Installation according to one of claims 10 to 21, characterized in that there is provided for the additive (8) a temperature setting device, preferably by means of a heating element arranged near the pipe. additive (10). 23. Installation according to one of claims 10 to 22, characterized in that one or more branches of distribution channels each have one or more additive pipes (10). 24. Installation according to one of claims 10 to 23, characterized in that several additive pipes (10) open into a channel leading to a molding cavity (5), if necessary in the same zone in the direction of flow, and in that these additive lines (10) can be selectively closed. 25. Installation according to one of claims 10 to 24, characterized in that the outlet orifice of the additive line (10) is produced in the form of an annular nozzle near the distribution channel. 26. Installation according to one of claims 10 to 25, characterized in that the additive line (10) has a supply line (11), a discharge device preferably formed by a pump (12), as well an additive storage tank (13). 27. Installation according to one of claims 10 to 26, characterized in that it is provided as an additive, dye, preferably fluid dye, granules, powder, metallic flakes or the like. . 28. Installation according to one of claims 10 to 27, characterized in that it forms an assembly operating in combination and comprising at least one injection molding machine (19), a withdrawal device (21), if necessary. a tamping device (24) and a further processing or finishing device and, if necessary, a packaging machine.