JPH0139354B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to the use of sticky substances such as glue or printing inks that need to be applied in a defined amount onto a given surface in order to form a thin film thereon. Relating to a dispensing device.

The following description refers in particular to printing units used to form letters, borders and/or repeat characters on packaging paper and/or packaging tissue, etc., using concentrated inks such as paste-like inks. The present invention relates to, but is not limited to, an apparatus for dispensing printing ink on a machine.

Currently, known dispensing devices can be divided into two main categories based on the way the sticky substance is delivered to the outlet nozzle.

The first category includes a dispensing device in which the sticky substance is disposed within an open top pan. In such devices, one example of which is described in British Patent No. 1,476,376, the sticky substance is manually loaded into the pan, usually using a thin spatula. A thin layer of sticky material is then drawn from this pan by a partially immersed rotating roller and then transferred via a series of intermediate adjacent rollers to the actual printing unit.

The above manual operations often result in the spillage of sticky substances from the pan, and as an inevitable consequence, especially if the sticky substance is a highly concentrated ink.
This will lead to extremely unpleasant results.

The second category includes, for example, British patent no.
No. 1,117,235, it includes a dispensing device configured to squeeze a sticky substance from a prefilled container, particularly a prefilled syringe or barrel.

In this case, any manual labor is eliminated, but it gives rise to other drawbacks, the main one being due to the fact that the delivery of the sticky substance is accompanied by a non-negligible elastic deformation of the container. If delivery is prevented, the walls of the container will act more elastically on the adhesive material to be delivered, causing it to extract even the excess and unwanted portion.

Furthermore, both types of dispensing devices described above are adversely affected by the air bubbles that inevitably occur in most sticky substances, and these air bubbles cause irregular delivery of the sticky substance.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to overcome the above-mentioned drawbacks and to provide a simple and economical sticky substance dispensing device.

This purpose, according to the invention, consists of a pot-like container for the sticky substance, an outlet nozzle, a connecting channel between said container and the nozzle, and a device for forcing the sticky substance present in said container towards the nozzle. a screw conveyor rotatably mounted within the container and in contact with the inner surface of the container; a threaded shank rotatably inserted through a through hole provided in the bottom of the container and forming a spiral passage connecting the container to the nozzle; and a seal for sealing the container. This is achieved by means of a device for dispensing a sticky substance, characterized in that means are arranged and flow control means of the connecting conduit are provided for controlling the flow of the sticky substance towards the nozzle.

Further features and advantages of the invention will become apparent from the following description with reference to the accompanying drawings. Although several embodiments are shown in the accompanying drawings, the present invention is not limited thereto.

Next, the present invention will be described in detail based on embodiments shown in the accompanying drawings.

FIG. 1 shows a device 1 for dispensing sticky substances, which device 1 is particularly suitable for use as an ink supply device for conveying concentrated ink via nozzles 2 to an ink roller 3 of a printing unit 4. The ink is in the form of a paste and is contained in a chamber 5 of a container 6 preferably made of metal. The container 6 is essentially cup-shaped and consists of a bottom wall or base portion 7 and side walls. The first part 8 of the container 6 is formed on the inside by a frustoconical inner surface 9 and is arranged between the base part 7 and the cylindrical end part 10 of the second part. The cylindrical end portion 10 of the second part has a cylindrical inner surface 11 that connects with the frustoconical inner surface 9 via an annular shoulder 12 and, at its free end, a cover that is removably inserted into the container 6. It cooperates with the sealing means of the chamber 5 consisting of 13.

A through hole 14 coaxial with the truncated conical inner surface 9 and the cylindrical inner surface 11 is formed through the base part 7 and has an annular shoulder facing the chamber 5 at its outer end. A reduced diameter portion 15 forming a diameter 16 is provided. A cylindrical shaft 17 is rotatably mounted through the through hole 14 and the small diameter portion 15, and one end portion of the shaft 17 projects outward from the base portion 7. This protruding portion is axially fixed to the base portion 7 by a fixing member 18, and is formed so as to be connectable to drive means (not shown) for rotating the cylindrical shaft 17.

On the cylindrical axis 17 there is a disc 19 cooperating with the annular shoulder 16
is provided, and an externally threaded cylindrical shaft portion 20 is also provided. This externally threaded cylindrical shaft portion 20 cooperates with the cylindrical inner surface of the through hole 14 to form a spiral passage 21 that communicates with the bottom of the chamber 5 at one end and with the annular chamber 22 at the other end. are doing. The annular chamber 22 is formed in the through hole 14 by an annular groove provided on the externally threaded cylindrical shaft near the disk 19. Further, the annular chamber 22 is connected to the guide path 23.
It communicates with nozzle 2 via. The conduits 23 are provided substantially radially through the base portion 7 and are controlled by flow control means comprising a needle valve 24 operable from the outside.

The part of the cylindrical shaft 17 extending through the chamber 5 is provided on the outside with a screw conveyor 25 of constant or variable pitch, which screw conveyor is in substantial contact with the frustoconical inner surface 9. It is in.

When operating, remove the cover 13 and then
An operator fills the chamber 5 with paste-like ink (not shown), preferably using a thin spatula. Although not shown, this ink is usually taken out from a large container, and when the cylindrical shaft 17 is rotated (in FIG. 1, clockwise when looking at the device from above), the ink is removed. By means of an axial extrusion means consisting of a conveyor 25 and a funnel formed by a frustoconical inner surface 9, it is compressed towards the through-hole 14 and then enters the helical passage 21 and further into the annular chamber 22. It reaches the nozzle 2 via the conduit 23.

Since the above-mentioned pasty ink is generally of very high concentration and therefore only a very small amount of ink per unit time must be properly supplied to the roller 3, the free opening of the conduit 23 must be kept to a minimum. It is almost always necessary to adjust the needle valve 24 to limit the amount of water.

Due to the very slow rotation of the cylindrical shaft 17 and the associated screw conveyor 25, the ink contained in the bottom of the chamber 5 is not only compressed towards the entrance of the spiral channel 21, but also agitated. Continuously maintained in the state.

Due to the continuous motion that the ink undergoes and the temperature increase possible due to both the compression and friction against the screw conveyor 25, air bubbles are removed and the fluidity of the ink is improved through the helical passage 21 and the nozzle 2. advantageously increases so that it flows evenly.

In this connection, the cover 13 is attached to the chamber 5.
The pressure exerted on the ink by the screw conveyor 25 is immediately dissipated upon stopping the rotation of the cylindrical shaft 17. Therefore, in the above-mentioned distribution device 1, not only is it possible to prevent frequent clogging of the nozzle 2 due to the intervention of foreign matter in the ink, but also it is possible to prevent ink from continuously dripping from the nozzle 2 even when the roller 3 is at rest. The risk of falling is also removed.

The only disadvantage of the dispensing device 1 described above is that the ink has to be manually transferred from the large container to the chamber 5. However, this disadvantage is eliminated in the modified embodiment shown in FIG. Thus, in this embodiment, ink is supplied to chamber 5 from a commercially available can 26.

As shown in FIG. 2, the cover 13 of the dispensing device 1
has been removed, and a can 26 has been placed in its place. The can is first opened and then inserted upside down into the cylindrical part 10 until its open end contacts the annular shoulder 12.

Although not shown, in one modification, the cylindrical portion 10 may be replaced by another cylindrical or funnel-shaped portion of a different diameter in order to adapt the container 6 to cans of various sizes. The cylindrical portion 10
The remaining portion of the container 6 is formed to be removable.

Before inserting the can 26, the cylindrical shaft 17
It has been suitably modified by the addition of stirring means comprising a spatula 27 which extends in and substantially contacts the bottom 28 of the can.

The spatula 27 is constituted by a substantially rectangular ring 29 made of metal wire, the opposite ends 30 and 31 of which are located at right angles to each other, and the cylindrical axis 17
It is engaged with a groove 32 in a direction perpendicular to the axial direction provided at the end of the plate, and is fixed by a fixing screw 33 in a direction perpendicular to the axis.

Upper edge portion 34 and side edge portion 3 of rectangular ring 29
5 separates the ink by moving in contact with the inner surfaces of the bottom wall 26 and side wall 36 of the can 26, respectively, and lowers the ink into the funnel formed by the truncated conical inner surface 9. promote.

As shown in FIG. 3, if the container 37 is of such dimensions that it cannot be attached directly to the container 6 in the manner described with reference to FIG. 5 can be automatically transferred. This means, for example, that container 37
two holes are provided in the lid, through which two tubular connecting members 38 and 39 are fitted with sealing means, and the first connecting member, i.e. connecting member 38, is connected to a source of compressed air (not shown). This is possible by arranging the second connecting member or connecting member 39 to have a dip tube 40 extending inside the container 37 and extending to near the bottom of the container.

In FIG. 3, the cover 13 of the dispensing device 1 is provided with through holes 41 and 42 through which an externally threaded conduit 43 is fitted and fixed to the cover 13 by a ring nut 44. ing. The conduit 43 constitutes an outlet of a valve or valve means 45 comprising an inlet connection member 43 and a through hole 47, said through hole 47 being slidable in a seat 49 provided in the valve 45 across said through hole. controlled by a perforated plate 48. The inlet connection member 46 is connected to the connection member 39 via a conduit 50, and the perforated plate 48 comprises an axle 51 connected to a magnetic core 52 or piston. The magnetic core 52 is controlled by a solenoid 53 and is in a normal rest position (shown in dotted lines) in which the perforated plate 48 closes the through hole 47.
From there, the perforated plate 48 is moved against the thrust of the spring 54 to an operating position where the perforated plate 48 opens the through hole 47.

Activation of the solenoid 53 is controlled by a circuit sensitive to the level of ink in the container 6, which circuit is mounted in an adjustable position, e.g. A capacitive sensor 5 connected to a limit comparison circuit 56 comprising
5, and the solenoid 53 is connected to a power source 57 via the comparison circuit 56.

In use of this device, compressed air is supplied into the container 37 via the connecting member 38 and forces the ink contained therein up along the dip tube 40 and the conduit 50, so that the ink is 45
, and stops facing the perforated plate 48 which is in the normal position with the through hole 47 closed.

During operation of the device 1, the level of ink in the container 6 is determined by the capacitive sensor 55. That is,
The sensor 55 determines the energization of the solenoid 53 and moves the perforated plate 48 when the distance from the surface of the ink to the lower surface of the sensor 55 exceeds a certain limit indicated by an arrow 58 as shown. and move it to the open position as shown. Therefore, the ink arriving from conduit 50 passes through conduit 43 to container 6.
and the level of ink in the container 6 is
It rises until it reaches the minimum distance from sensor 55, which is indicated schematically by arrow 59. At this point of rise, the capacitive sensor 55 via the limit comparison circuit 56 stops the current supply to the solenoid 53, thus allowing the perforated plate 48 to return to its normal closed position by the thrust of the spring 54. let and,
The above cycle is repeated until all the ink contained in the container 37 is used.

Due to sticky substances it may be necessary to keep the dispensing device 1 at a strictly constant pressure. In order to satisfy this requirement, pressure is measured near the outlet of the nozzle 2, and the variable speed motor 61 is controlled by the action of this pressure.
A device 60 can be provided for controlling the rotational speed of the shaft 17 via.

Within the scope of the principles of the invention and without departing from the scope of the invention or being limited to the embodiments illustrated and described, the dispensing device of the invention may be modified in various ways. It is.

[Brief explanation of drawings]

1 is an axial sectional view of a dispensing device for adhesive substances, in particular printing inks, according to the invention; FIG. 2 is an axial sectional view of a first modification of the device shown in FIG. 1; FIG. 2 is a partially cutaway view of a second modification of the device shown in FIG. 1; FIG. 1... Adhesive substance dispensing device, 2... Nozzle,
5... Chamber, 6, 37... Container, 9... Frame-shaped inner surface, 13... Cover, 14... Through hole, 17
... Cylindrical shaft, 20 ... Cylindrical shaft portion with external thread, 21
... spiral passage, 22 ... annular chamber, 23 ... connection conduit, 24 ... needle valve, 25 ... screw conveyor, 26 ... can, 27 ... spatula, 29 ...
Rectangular ring, 45... Valve means (valve), 50...
Supply conduit, 60...Pressure measurement and control device, 61
...Variable speed motor.

Claims (1)

[Claims] 1. A pot-shaped container 6 for sticky substances, an outlet nozzle 2, and a connecting channel 23 between the container 6 and the nozzle 2.
and extrusion means 9, 25 for forcibly discharging the sticky substance present in the container 6 toward the nozzle 2.
A dispensing device for a sticky substance comprising: a screw conveyor 25 rotatably mounted in the container 6 and in contact with the inner surface of the container; The container 6 is rotatably mounted through a provided through hole 14 and
and a threaded shaft 20 forming a spiral passage 21 communicating with the nozzle, and further provided with sealing means for sealing the container and preventing the flow of the sticky substance toward the nozzle 2. A device for dispensing a sticky substance, characterized in that a flow rate control means 24 is disposed within the conduit 23 for controlling the flow rate. 2. The sticky substance dispensing device according to claim 1, wherein the inner surface of the container in contact with the screw conveyor has a truncated conical shape. 3 The above-mentioned threaded shaft portion 20 and screw conveyor 2
5 is supported on a shaft 17 which is rotatably mounted in an axially fixed position via said container 6. Device. 4 an annular chamber 2 surrounding the threaded shank 20 for connecting the helical passage 21 to the conduit 23;
Claims 1 to 3 in which 2 is provided.
A device for dispensing a sticky substance according to any of the items. 5. The adhesive substance dispensing device according to any one of claims 1 to 4, wherein said flow rate control means comprises an adjustable needle valve (24) mounted on said conduit (23). 6. The adhesive substance dispensing device according to any one of claims 1 to 5, wherein the sealing means is a cover 13 removably attached to the container. 7. The sealing means includes a can 26 containing the adhesive substance and mounted upside down on the container 6, and is supported by the screw conveyor 25 and extends outside the container 6 and inside the can. 6. A sticky substance dispensing device according to any one of claims 1 to 5, comprising a screw conveyor 25 and movable stirring means. 8. The adhesive substance dispensing device according to claim 7, wherein the stirring means comprises a spatula 27 constituted by an annular metal wire element. 9 The container 6 communicates via a supply conduit 50 with the external pressurized container 37 for the sticky substance, in which valve means 45 are arranged, the valve means 45 being connected to the container 6. 6. The supply conduit 50 is closed and opened in response to an increase and decrease, respectively, within a defined range of changes in the level of a sticky substance within the supply conduit 50. The adhesive substance dispensing device described in . 10 Patent comprising a device 60 for measuring the pressure of the sticky substance flowing through the nozzle 2 and thereby controlling the rotational speed of the motor 61 for driving the shaft 17 based on the action of the measured pressure An adhesive substance dispensing device according to any one of claims 1 to 9.