Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
  • G01F23/14—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measurement of pressure
  • G01F23/16—Indicating, recording, or alarm devices being actuated by mechanical or fluid means, e.g. using gas, mercury, or a diaphragm as transmitting element, or by a column of liquid
  • G01F23/162—Indicating, recording, or alarm devices being actuated by mechanical or fluid means, e.g. using gas, mercury, or a diaphragm as transmitting element, or by a column of liquid by a liquid column
• • 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
  • B41J2/17566—Ink level or ink residue control
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01F—MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME
  • G01F23/00—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm
  • G01F23/14—Indicating or measuring liquid level or level of fluent solid material, e.g. indicating in terms of volume or indicating by means of an alarm by measurement of pressure
  • G01F23/16—Indicating, recording, or alarm devices being actuated by mechanical or fluid means, e.g. using gas, mercury, or a diaphragm as transmitting element, or by a column of liquid
  • G01F23/161—Indicating, recording, or alarm devices being actuated by mechanical or fluid means, e.g. using gas, mercury, or a diaphragm as transmitting element, or by a column of liquid for discrete levels
• • 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
  • B41J2/17566—Ink level or ink residue control
  • B41J2002/17576—Ink level or ink residue control using a floater for ink level indication

Definitions

• the present invention relates to a device for indicating a 10 certain liquid level in a container according to the preamble of claim 1.
• the invention further relates to the use of such a device in an ink-jet printer apparatus.
• the object of the present invention is to provide a device for indicating when the level of liquid in a container drops below a predetermined value, which device
• Fig. 1 is a schematic representation of an embodiment of the device according to the invention attached to a container of liquid before any liquid is drawn from the container;
• Fig. 2 is a schematic representation of a preferred embodiment of the present invention connected to a printhead unit of a printing device.
• Fig. 3 is a schematic sketch showing the principle of operation of an ejector assembly used in the present invention
• Fig. 4 shows the device according to Fig. 1 in a steady- state operating mode
• Fig. 5 shows the same device when the liquid level drops below that which is to be indicated.
• a container of liquid is indicated by reference numeral 1.
• a connector head 2 is attached to the top of the container by an operator in a conventional manner, e.g. via a screw fit, push fit, etc.
• the connector head 2 is provided with a plurality of through-bores to which a corresponding number of conduits 3, 4, 5, 6, 7 are connected at either end of said through- bores.
• the through-bores may allow conduits to pass therethrough, as schematically represented in the drawings.
• the conduits which extend into the container 1 are surrounded by a section of tube 20 which seals against a ring-seal 21 in the upper surface of the container 1 .
• this section of tube 20 is pushed through the ring-seal 21 in the upper surface of the container, thereby ensuring a rapid yet secure attachment of the connector head.
• any risk of damage to the conduits 3,4,5,6,7 during insertion is greatly reduced.
• section of tube can replace the function of one of the conduits, for example the conduit 5, as shown in Fig. 2. Accordingly, the section of tube 20 is provided with a through hole 22 positioned above the level of liquid in the container.
• Conduits 3 and 4 pass from the container 1 substantially vertically through the connector head 2 as shown in the drawings and terminate within an indicator bowl 8 sealingly affixed to an upper surface of the connector head 2.
• the indicator bowl 8 is made from a suitable, transparent or semi-transparent material such as glass or plexiglass so that any liquid contents therein are easily visible.
• conduit 3 has its lower opening at the height above the base of the container which corresponds to the selected indication level of the liquid.
• Conduit 4 meanwhile has its lower opening somewhat closer of the base of the container 1.
• Conduit 5 is optional and in the shown embodiment it provides a connection between the space in the container above the liquid surface and atmosphere. The purpose of this is to equalize the pressure in the container and, as such, any gaseous medium can be used.
• Conduit 6 has its lower opening at approximately the same level as that of conduit 4. Conduit 6 serves as a withdrawal pipe for withdrawing the liquid from the container and is thus connected to the suction side of a liquid pump unit 9 mounted exteriorally of the container.
• a delivery pipe 10 runs from the pressure side of the pump unit to a T-connector 11.
• One conduit 12 from the T- connector forms a part of a recirculation circuit, whilst the other conduit 13 leads to a place of consumption, in this case the print-head 23 of an ink-jet printer.
• the pumping pressure of the pump unit 9 may be varied, as schematically indicated in the drawings.
• the return conduit 12 terminates with a nozzle 15 of an ejector assembly 16 mounted in the connector head 2.
• the ejector assembly 16 further comprises a cavity 17 from which a suction tube 18 extends into the indicator bowl 8 to a level almost corresponding to the height of said bowl.
• a passage forming a second nozzle 19, coaxial with, and of larger diameter than, the first nozzle 15, is provided in the end of conduit 7.
• Conduit 7 is of larger diameter than the second nozzle 19 and passes through the connector head 2 to emerge into the container to terminate with an opening at approximately the same level as the openings to conduits 4 and 6. This assures that liquid flowing into the container 1 via the conduit 7 is discharged below the level of the liquid already in the container, thereby preventing undesireable frothing of the contents of the container.
• Fig. 1 the connector head 2 is shown immediately after having being attaching to the container 1 for the appropriate liquid.
• the space above the surface of the liquid in the container is occupied with air at atmospheric pressure.
• the indicator bowl 8 also contains air at substantially atmospheric pressure.
• the pump 9 is now actuated and liquid is drawn up the withdrawal pipe 6 and through the pump 9 , the delivery tube 10 to the T-connector 11. A major quantity of liquid then flows into the return conduit 12, and the remainder flows under pressure through conduit 13 to its place of consumption.
• the liquid in the return conduit 12 reaches the ejector assembly 16 in the connector head 2 it is forced at high velocity through the nozzle 15, thereby forming a jet of liquid directed towards the second nozzle 19 in the conduit 7.
• a partial vacuum, or region of lower pressure is created in the vicinity of the jet of liquid emerging from said nozzle 15.
• This low pressure region draws the air from the indicator bowl 8 via suction tube 18 into the cavity 17. The air is then removed in the flow of liquid along conduit 7 to the container 1.
• a float 24 may be included in the indicator bowl to help identify when there is liquid in the bowl.
• the float may be provided with an electrical contact on its surface facing the upper sur ace of the indicator bowl for cooperation with a corresponding contact positioned thereon, the purpose of which will be explained in the following.
• the volume of the indicator bowl is chosen to be very much smaller than the volume of the container 1, then the whole indicator bowl 8 is emptied of liquid in a matter of moments. This rapid emptying of the indicator bowl is clearly visible to the operator who is thus informed that the liquid in the container has reached a level at which the container must be replenished or exchanged.
• a plurality of containers may be selectively connectable to the pump unit 9 so that when one container is emptied, another may be connected to the system at the throw of a switch. If a float is employed as described above, then the electrical contacts thereon can form the switch for connecting another container when this contact is broken. Such an arrangement is not shown in the drawings. The emptied container can then be decoupled from the connector head and replaced by a full container.
• a pressure differential sensing means can also be arranged in the indicator bowl which measures the difference in pressure between the indicator bowl and the container 1. Since the difference in pressure is directly proportional to the difference in liquid levels, the depth of remaining liquid in the container 1 can be easily determined.
• the invention is not restricted to the embodiments described above, but may be varied within the scope of the appended claims.
• the device may also function with just one conduit 3 whose lower opening is at the height above the base of the container 1 which corresponds to the selected indicaton level of the liquid. Whether the device will work satisfactorily with one conduit depends upon the viscocity of the liquid in the container 1 and the capillary force generated in the conduit 3 when the level of liquid drops below the lower opening of the conduit 3.
• the outlet from the pump unit 9 may be directly connected to the nozzle 15 of the ejector assembly 16, with liquid being drawn from the container for use at its place of consumption via, for example, an opening in the base of the container.
• the pump unit 9 may be used solely to operate the ejector assembly 16.
• the T-connector 11 and/or the pump unit 9 can be incorporated in/on the connector head 2.
• the indicator bowl need not be mounted on the connector head 2, but may be positioned at closer proximity to the operator.

Landscapes

• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• General Physics & Mathematics (AREA)
• Ink Jet (AREA)
• Measurement Of Levels Of Liquids Or Fluent Solid Materials (AREA)
• Devices For Dispensing Beverages (AREA)

Priority Applications (1)

Applications Claiming Priority (4)

Publications (1)

Family

ID=26660945

Family Applications (1)

Country Status (5)

Cited By (3)

Citations (6)

• 1991
  • 1991-04-22 SE SE9101201A patent/SE9101201D0/sv unknown
  • 1991-12-16 AU AU91089/91A patent/AU9108991A/en not_active Abandoned
  • 1991-12-16 EP EP19920901936 patent/EP0563207A1/en not_active Ceased
  • 1991-12-16 WO PCT/SE1991/000862 patent/WO1992011513A1/en not_active Application Discontinuation
  • 1991-12-16 JP JP4501792A patent/JPH06504618A/ja active Pending

Patent Citations (6)

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