Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
  • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
  • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
  • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
  • B41J2/01—Ink jet
  • B41J2/17—Ink jet characterised by ink handling
  • B41J2/175—Ink supply systems ; Circuit parts therefor

Definitions

• the invention relates to a coating device with a pump, a writing fluid container for receiving a writing liquid and a writing head, a first line and a second line being provided through which compressed air can be guided from the pump into the writing liquid container or the writing liquid to the writing head. Furthermore, the invention relates to an extrusion system with such a labeling device.
• DE 41 12 033 C2 discloses a device for writing and drawing, in particular for a plotter.
• the device described has a pump, a chamber which is divided into two sections by a movable piston and a writing head.
• the pump drives compressed air through a first line into the first section of the chamber so that pressure is applied to the piston.
• the second section of the chamber houses the ink, which is driven to the write head through a second line due to the pressure transferred by the piston.
• a pressure sensor is arranged in the first line and measures the pressure within the first line.
• the plunger When the ink is completely pushed out of the second section of the chamber, the plunger has come into a position in which the air from the first section, past the plunger, passes through the second section, the second line and the writing head, so that a pressure drop is caused in the first line.
• This pressure drop is detected by means of a pressure sensor in the first line in order to output a signal which indicates the exhausted ink supply.
• the known device for writing and drawing has the disadvantage that if the second line is damaged, such as. B. a burst of the same, the ink can flow freely. On the one hand, this leads to contamination of the product to be labeled and, on the other hand, to an increased risk of fire if flammable ink is used.
• a labeling device which has a monitoring device for measuring the pressure in a feed tube.
• the supply quantity and pressure are to be regulated here.
• the invention is therefore based on the object of providing a labeling device which prevents leakage of the writing fluid caused by leakage or the like. Furthermore, the invention has for its object to provide an extrusion system with such a labeling device.
• the invention provides a labeling device with a pump, a writing fluid container for holding a writing liquid and a writing head.
• a first line is arranged between the pump and the writing liquid container, through which the compressed air of the pump can be pressed into the writing liquid container.
• a second line is provided, through which the writing liquid can be pressed from the writing liquid container to the writing head.
• a monitoring device for measuring the pressure and for comparing the measured pressure with a predetermined pressure limit value is provided in the second line. The pressure within the second line is always above the predetermined pressure limit during operation of the labeling device and when the second line is intact. Should a hole, a crack or the like occur in the second line, the drop below the pressure limit value would be determined by the comparison carried out by the monitoring device, whereupon the writing fluid container is vented.
• a crack or hole in or bursting of the second line is determined. Due to the subsequent venting of the writing liquid container, the pressure within the writing liquid container is reduced, so that no more writing liquid is pressed into the second line, which would otherwise escape through the hole or the like.
• a shut-off device is provided in the first line, which can be transferred from a flow position into a shut-off position, in which the pump is locked and the container is vented.
• a shut-off device can be formed, for example, by a valve which is arranged within the first line and divides it into sub-lines. In the flow position, such a valve would connect the partial lines to one another, while in the shut-off position the partial line leading to the pump would be blocked and the partial line leading to the writing fluid container would be vented.
• the monitoring device in a preferred embodiment comprises a third line branching off the second line with a pressure switch connected to it.
• the pressure switch is connected to the shut-off device via a first control line, via which control signals for the shut-off device can be passed.
• Under a pressure switch is a mechanical one To understand switch, which is in a first position at a pressure above the predetermined pressure limit and changes to a second position when the pressure falls below the predetermined pressure limit, the switching point being variable. This represents a particularly simple measuring and comparison method.
• the second line is arranged above the writing fluid container in such a way that the writing fluid flows back into the vented writing fluid container. In this way it is ensured that the writing liquid present in the second line does not remain within the second line after the hole or the like has formed and thus runs out, but instead flows back into the writing fluid container due to its own weight. The prerequisite for this, however, is that the capillary action within the second line is low.
• a pressure reducing device is advantageously provided in the first line, so that pressure fluctuations can be largely prevented.
• At least one filter is provided in the second line, which filters out the impurities and particles present in the writing liquid.
• the write head has at least one nozzle which is controlled by a control unit.
• the control unit is connected to the monitoring device via a second control line, via which control signals for the monitoring device can be routed. If all the nozzles of the Are closed, the control unit sends a corresponding signal to the monitoring device via the second control line, which in turn specifies a higher predetermined pressure limit.
• This embodiment is advantageous in that the opening of the nozzles also causes a certain pressure drop within the second line. Since this pressure drop should not be regarded as damage to the line, the specified pressure limit is chosen to be correspondingly small.
• the control unit enables the predetermined pressure limit value to be adapted accordingly, so that even the smallest damage to the second line can be detected.
• the monitoring device is arranged in a preferred embodiment of the labeling device such that the pressure within the second line is measured directly in front of the write head.
• the extrusion system according to the invention has a labeling device of the type described above, the labeling device being used to label the extruded material.
• a secure or leak-proof labeling device is necessary, since often highly inflammable writing fluid is used. Leakage of the writing fluid would contaminate the extruded material, but more serious is that when protective films are applied to the extruded material, static charges can discharge, which ultimately cause the flammable writing fluid to ignite.
• a labeling device for the operator, the extruded material and the extrusion system represents a significant This danger is eliminated with the help of the labeling device described above.
• Fig. 1 is a schematic representation of the invention
• Labeling device Fig. 2, the labeling device of Fig. 1 with bursting second
• FIG. 3 shows the labeling device of FIG. 1 after the second line has burst
• FIG. 4 shows a time-pressure diagram for the labeling device according to FIGS. 1 to 3
• FIG. 5 shows a time-pressure diagram for the labeling device to
• Fig. 1 in a modified embodiment.
• Fig. 1 shows a schematic representation of the labeling device according to the invention.
• the labeling device according to the invention has a pump 2, which is connected to a writing fluid reservoir 6 via a first line 4.
• the first line 4 projects into an upper area of the writing liquid container 6, which is filled with a writing liquid 8.
• the writing liquid 8 can be an ink, such as. B. water-based, ethanol, isopropanol, ethyl acetate, MEK, high temperature or special ink.
• a second line 10 extends from the writing fluid container 6 to a writing head 12.
• the writing head 12 has a plurality of nozzles 14 which can be opened or closed by means of a control unit 16.
• a filter 18 for filtering the writing fluid 8 is also arranged in the second line 10, while a pressure reducing device 20 in the form of a valve is arranged in the first line 4.
• the pressure switch 24 is on in the illustrated embodiment mechanical switch which is in a first position at a pressure above a predetermined pressure limit value and changes to a second position when the pressure falls below the predetermined pressure limit value.
• the pressure switch 24 is connected to a shut-off device 28 via a first control line 26, and the pressure switch 24 is also connected to the pump 2 via a further control line 30, the control line 30 being optional.
• the shut-off element 28 is arranged within the first line 4 and can be transferred from a flow position (FIGS. 1 and 2) to a shut-off position (FIG. 3), in which the pump 2 is blocked and the writing fluid container 6 is vented.
• Fig. 1 shows the labeling device in normal undisturbed operation.
• the pump 2 presses air through the first line 4, via the pressure reducing device 20 and the shut-off element 28, which is located in the flow position, into the writing liquid container 6.
• an air bubble forms, which is due to the pump 2 generated pressure on the underlying writing fluid 8 presses.
• the writing liquid 8 is driven into the second line 10 up to the writing head 12 and into the third line 22 of the pressure switch 24, the writing liquid 8 being filtered by the filter 18.
• the pressure within the second or third line 10, 22 is above a predetermined pressure limit value 32 (FIG. 4) when the labeling device is in undisturbed operation.
• the nozzles 14 are now opened or closed by the control unit 16 depending on which character is to be written on the workpiece.
• 4 shows in section a of the diagram shown the course 34 of the pressure p in the second or third The line 10, 22 over time t for FIG. 1. The more nozzles 14 are opened, the more the pressure p drops, but does not drop below the predetermined pressure limit value 32, even if all nozzles 14 are open.
• FIG. 2 shows the labeling device when the second line 10 bursts at a point A at time ti.
• the pressure p within the second or third line 10, 22 drops, as is shown in section b of the diagram shown in FIG. 4.
• the pressure switch 24 changes from the first position to the second position described above, whereupon a corresponding signal is sent via the first control line 26 to the Shut-off device 28 is transmitted.
• the shut-off device 28 is transferred by the signal from the flow position into the shut-off position (FIG. 3).
• the part of the first line 4 which extends from the pump 2 to the shut-off device 28 is closed, whereas the part of the first line 4 which extends between the shut-off device 28 and the writing fluid container 6 is vented, so that the air can escape from the writing liquid container 6 through the first line 4 and the shut-off element 28 in the direction of the arrow 36.
• FIG. 4 also shows the case in which there is only one hole in the second line 10, which does not lead to a complete pressure loss (dash-dotted line). In this case too, the labeling device according to the invention reacts in the manner described above.
• a second control line 38 is provided between the control unit 16 and the pressure switch 24.
• a corresponding signal can be sent to the pressure switch 24 via the second control line 38, as a result of which the predetermined pressure limit value 40 (FIG. 5) is increased.
• the predetermined pressure limit value 40 FIG. 5
• pressure drops can now be registered which are caused by the smallest holes in the second line 10 and not by open nozzles 14.
• a new signal is emitted via the signal line 38, so that the predetermined pressure limit value 40 is reduced again to the original value.
• the operating pressure of the writing fluid in the second line was approximately 250 mbar, the predetermined pressure limit being approximately 180 mbar.

Landscapes

• Ink Jet (AREA)
• Coating Apparatus (AREA)
• Extrusion Moulding Of Plastics Or The Like (AREA)
• Package Frames And Binding Bands (AREA)
• Labeling Devices (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=7663389

Family Applications (1)

Country Status (5)

Families Citing this family (3)

Family Cites Families (7)

• 2000
  • 2000-11-15 DE DE10056602A patent/DE10056602C1/de not_active Expired - Fee Related
• 2001
  • 2001-10-23 WO PCT/EP2001/012200 patent/WO2002040274A1/fr active IP Right Grant
  • 2001-10-23 DE DE50108698T patent/DE50108698D1/de not_active Expired - Fee Related
  • 2001-10-23 AT AT01980507T patent/ATE315479T1/de not_active IP Right Cessation
  • 2001-10-23 AU AU2002212336A patent/AU2002212336A1/en not_active Abandoned
  • 2001-10-23 EP EP01980507A patent/EP1333983B1/fr not_active Expired - Lifetime

Non-Patent Citations (1)

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