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
  • B41J2/17503—Ink cartridges
  • B41J2/17556—Means for regulating the pressure in the cartridge
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D16/00—Control of fluid pressure
  • G05D16/20—Control of fluid pressure characterised by the use of electric means
  • G05D16/2006—Control of fluid pressure characterised by the use of electric means with direct action of electric energy on controlling means
  • G05D16/2013—Control of fluid pressure characterised by the use of electric means with direct action of electric energy on controlling means using throttling means as controlling means
  • G05D16/2026—Control of fluid pressure characterised by the use of electric means with direct action of electric energy on controlling means using throttling means as controlling means with a plurality of throttling means
  • G05D16/2033—Control of fluid pressure characterised by the use of electric means with direct action of electric energy on controlling means using throttling means as controlling means with a plurality of throttling means the plurality of throttling means being arranged in series
• • G—PHYSICS
  • G05—CONTROLLING; REGULATING
  • G05D—SYSTEMS FOR CONTROLLING OR REGULATING NON-ELECTRIC VARIABLES
  • G05D16/00—Control of fluid pressure
  • G05D16/20—Control of fluid pressure characterised by the use of electric means
  • G05D16/2006—Control of fluid pressure characterised by the use of electric means with direct action of electric energy on controlling means
  • G05D16/208—Control of fluid pressure characterised by the use of electric means with direct action of electric energy on controlling means using a combination of controlling means as defined in G05D16/2013 and G05D16/2066
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T137/00—Fluid handling
  • Y10T137/2931—Diverse fluid containing pressure systems
  • Y10T137/3115—Gas pressure storage over or displacement of liquid
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T137/00—Fluid handling
  • Y10T137/2931—Diverse fluid containing pressure systems
  • Y10T137/3115—Gas pressure storage over or displacement of liquid
  • Y10T137/3127—With gas maintenance or application

Definitions

• the invention relates to methods and regulating devices intended in particular for vacuum devices applied to maintaining a liquid in an open reserve, the opening being situated below the level of the liquid, so as to block the flow of the liquid caused by gravity.
• the invention is particularly applicable to the heads of printing systems of the “inkjet” type.
• These printheads consist of an ink tank provided with an opening situated below the ink filling level and of means, in particular piezoelectric, for projecting a fine drop of ink through the opening, towards the medium to be printed. It is by projecting a multitude of these fine drops in the appropriate locations that we achieve the desired impression. Outside the projection phases, the ink must be kept in its reserve despite the gravity which encourages it to flow through the opening.
• An effective solution consists in maintaining the gas present in the reserve above the ink at a pressure below atmospheric pressure, with the use of a vacuum device.
• Maintaining the ink correctly inside an inkjet printhead requires very precise regulation of the vacuum to prevent the ink from flowing through the opening if the vacuum is too low. , or the air intake through this same opening if the vacuum is too strong.
• Such methods and devices for regulating depression are known in the prior art.
• US Pat. No. 5,189,438 describes a device in which a vacuum pump is connected to the ink reserve, above the ink level, and is permanently activated.
• the setting of the vacuum is obtained thanks to a calibrated leak orifice, also located above the ink level.
• the known devices do not have adjustment of the vacuum setpoint to be maintained in the ink reserve. Changing the setpoint amounts to physically changing the exhaust port with an opening of another caliber, which cannot be done dynamically during the operation of the print head.
• the object of the invention is to overcome these drawbacks of the prior art.
• the invention firstly relates to a method for regulating means for pressurizing negative or positive pressure of a reserve of liquid, for example ink, further containing a gas, for example intended for an ink jet type print head, characterized in that it comprises the steps providing for: a) defining a pressure setpoint around which the gas present in the reserve must be maintained; b) measure the instantaneous pressure of the gas present in the reserve; c) compare the measurement of the instantaneous pressure of the gas present in the reserve with the pressure setpoint; d) in the case where the measurement of the instantaneous pressure of the gas present in the reserve is greater than the pressure setpoint, create a calibrated volume of gas in depression then put it in communication with the reserve; e) in the case where the measurement of the instantaneous pressure of the gas present in the reserve is less than the pressure setpoint, create a calibrated volume of gas under pressure then put it in communication with the ink reserve.
• pressurized gas is meant a gas whose pressure is higher than the pressure setpoint.
• vacuum gas is meant a gas whose pressure is lower than the pressure setpoint.
• the process described therefore applies either to the regulation of a vacuum, if the pressure setpoint is lower than the atmospheric pressure, or to the regulation of an overpressure, if the pressure setpoint is higher than atmospheric pressure.
• the regulation of the vacuum is therefore established by injecting into the liquid reserve a gas at high pressure (greater than the pressure setpoint) when the vacuum is too strong or by evacuating from the liquid reserve a gas at high pressure (greater than the pressure setpoint) when the vacuum is too low.
• the resolution of the regulation depends above all on the calibrated volume of gas injected into or evacuated from the liquid reserve. It is therefore easy to obtain a resolution of less than 10 Pa (0.1 millibar) depending on the calibration of this volume of gas created, and independently of the control system used to implement the method according to the invention, whether for example a microcomputer, an automaton or a device with wired logic gates.
• the efficiency of the process is independent of the pressure level to be regulated; it is all the more justified for low-value depressions (very close to atmospheric pressure, while remaining lower) which are the most difficult to maintain.
• the steps of measurement (b), of comparison (c) and those of creation of volume then of communication (d or e) can be repeated successively at regular intervals. It is also possible to define a new pressure setpoint during the process, the steps of measurement (b), of comparison (c) and those of volume creation then of communication (d or e) being carried out successively by taking account of the new pressure setpoint if this setpoint is redefined.
• the method according to the invention then constitutes a control loop guaranteeing that each time the pressure setpoint is changed, the internal pressure of the liquid reserve will be regulated accordingly.
• the method according to the invention comprises, before the measurement step (b), a step providing for: ai) defining a minimum pressure threshold pressure value for rapid regulation and a maximum threshold pressure pressure value fast, these two values framing the pressure setpoint; and, before the comparison step (c), the steps providing for: b1) comparing the measurement of the instantaneous pressure of the gas present in the reserve with the minimum and maximum threshold pressure values for rapid regulation; b2) in the event that the instantaneous pressure of the gas present in the reserve is greater than the maximum rapid regulation threshold pressure, connect the reserve to a continuous source of vacuum gas until reaching in the reserve a pressure close to the setpoint pressure; b3) in the event that the instantaneous pressure of the gas present in the reserve is lower than the minimum threshold for rapid regulation, connect the reserve to a continuous source of gas under pressure until a pressure close to the pressure setpoint is reached in the reserve.
• the regulation is carried out in two successive phases:
• the pressure setpoint comprises a minimum setpoint pressure pressure value and a maximum setpoint pressure pressure value.
• the subject of the invention is also a regulating device intended for a negative or positive pressurizing device itself intended for a printing head in which a reserve of liquid additionally contains a gas, this device being intended for the implementation of the method described above and comprising:
• auxiliary gas reserve makes the device reliable and insensitive to the control system since it does not use the switching or control speeds of any actuators used, such as solenoid valves.
• This regulation device can also comprise means for selecting the pressure set point to be kept in the liquid reserve, said means also making it possible to modify the set point during the operation of the regulation device.
• the device may further comprise means for directly placing the loading means in contact with the liquid reserve.
• the transfer means comprise a first solenoid valve connecting the annex reserve with either the loading means or the liquid reserve.
• the means of direct connection of the loading means with the liquid reserve comprise a second solenoid valve connecting the loading means with either the auxiliary reserve or directly the liquid reserve.
• the subject of the invention is also a device for negative or positive pressurization intended for a printhead, for example of the inkjet type, in which a reserve of liquid to be printed additionally contains a gas, this device comprising a pressurized gas supply, a vacuum gas supply as well as a regulating device as described above.
• the loading means comprise a third solenoid valve receiving at the inlet the supply of gas under pressure and the supply of gas under vacuum and delivering at the outlet one or the other of these supplies.
• the subject of the invention is also a printing machine on a plastic support comprising a printing head provided with a reserve provided with an opening and intended to contain the liquid to be printed as well as a gas, and further comprising a device as described above.
• the invention finally relates to an installation for manufacturing intelligent portable objects, such as chip cards, CD or CD-ROM, comprising at least one graphic personalization station consisting of a printing machine as described below. above.
• FIG. 1 shows an ink supply of an ink jet type print head, side view in section
• - Figure 2 is a block diagram of a vacuum device according to the invention
• FIG. 3 schematically shows an installation according to the invention for manufacturing intelligent portable objects
• FIG. 4 is a diagram illustrating an example of operation of the invention.
• a liquid reserve 1 (FIG. 1) is used here in the ink jet type print heads. Its volume is of the order of 10 5 mm 3 (100 cm 3 ) and it contains an ink 3, a gas 4 and is provided with an opening 2 through which the drops of ink which eject on the support.
• a liquid other than ink can be used to fill the reserve (1) of liquid, such as a liquid having adhesive or electrical conduction properties.
• the volume of gas 4 is for example between 10 "mrrr
• the gas 4 is maintained at a pressure below atmospheric pressure thanks to a vacuum device connected to an orifice 5 in contact with the gas 4. It is a device for slaving to a desired working pressure.
• a vacuum device consisting of a supply 6 of pressurized gas, of a supply 7 of vacuum gas as well as a regulation device making the interface between these supplies and the reserve 1, the conduit 8 for output from the regulating device which is connected to the orifice 5 of the reserve 1.
• the regulating device is formed by three identical solenoid valves 9, 10, 11 here and of the monostable type with three channels and two positions, an auxiliary reserve 12, an industrial programmable controller 14, an input interface 15, as well as a vaccuostat 13 allowing a measurement of depression.
• the pressure to be maintained in reserve 1 has a negative value.
• the invention also applies to positive pressure regulations, for example to purge the reserve 1 of the liquid that it contains.
• the annex reserve is presented as a sealed enclosure of 5 mm 3 from which a conduit leaves.
• the automaton 14 receives the pressure measurement from the vaccuostat 13 as input and controls each of the three solenoid valves 9, 10, 11 as output.
• the input interface 15 is also connected to the input of the automatic device 14 and allows entry into the internal memory of the latter of threshold pressure values necessary for the operation of the device.
• the first solenoid valve 9 connects, in the rest state, the annex reserve 12 to an input of the second solenoid valve 10 and, in the actuated state, the annex reserve 12 to the conduit 8 connected to the ink reserve 1.
• the second solenoid valve 10 connects, in the idle state, an input of the third solenoid valve 11 to the conduit coming from the first solenoid valve 9 and, in the actuated state, the same input of the third solenoid valve 11 to the conduit 8 connected to the ink supply 1.
• the third solenoid valve 11 connects, in the idle state, the conduit issuing from the second solenoid valve 10 to the vacuum gas supply 7 and, in the actuated state, the conduit issuing from the second solenoid valve 10 to the supply in pressurized gas 6.
• the vacuum gas supply 7 is connected to the annex reserve 12, via the second 10 and third 11 solenoid valves;
• the conduit 8 connected to the ink reserve 1 is itself connected to the vaccuostat.
• the controller 14 has in its memory four pressure thresholds which have been communicated to it by means of the input interface 15: - a minimum threshold for rapid regulation
• the pressure values of the minimum and maximum setpoint thresholds very closely surround the value of the pressure that one wishes to maintain inside the liquid reserve 1 and thus define the low and high limits between which the regulation of the pressure will be achieved by the transfer of gas volumes between the annex 12 reserve and the liquid reserve 1.
• the pressure values of the minimum and maximum rapid regulation thresholds frame the setpoint thresholds and define the low and high limits beyond which the triggering of a direct connection of the ink reserve 1 to l will take place.
• the automaton 14 manages these four thresholds by regularly reading, thanks to the vaccuostat 13, the value of the pressure in the ink reserve 1 and by actuating the solenoid valves 9, 10, 11 according to the following principle:
• the first solenoid valve 9 makes it possible either to charge the annex reserve 12 with gas under pressure or under vacuum, or to put the reserve 12 in communication with the ink reserve 1, the second solenoid valve 10 being maintained in the rest state;
• the second solenoid valve 10 makes it possible to connect the pressurized gas 6 or vacuum 7 supplies either to the annex reserve 12 for loading, or directly to the ink reserve 1 for rapid regulation;
• the third solenoid valve 11 allows the selection between the supply of pressurized gas 6 and the supply of vacuum gas 7. According to the invention, the device whose structure has just been described operates in the manner indicated below.
• the user first enters the four threshold values into the memory of the controller 14 and puts it into service.
• the automaton 14 then creates a control loop by controlling the pressure of the gas present in the ink reserve 1 and by acting on the three solenoid valves 9, 10, 11 to maintain this pressure between the two set thresholds.
• a possible first phase of rapid regulation occurs in the case where the value of the pressure in the ink reserve 1 is outside the interval formed by the two rapid regulation thresholds.
• the ink reserve 1 When the value of the pressure in the ink reserve 1 is lower than the minimum value for rapid regulation threshold pressure, the ink reserve 1 is connected directly to the pressurized gas supply 6 so that its internal pressure quickly reaches the maximum threshold for rapid regulation.
• the first solenoid valve 9 is left in the rest position, the second solenoid valve 10 is activated and the third solenoid valve 11 is activated.
• the ink reserve 1 when the value of the pressure in the ink reserve 1 is greater than the maximum rapid regulation threshold pressure value, the ink reserve 1 is connected directly to the vacuum gas supply 7 so that its internal pressure quickly reaches the minimum threshold for rapid regulation.
• the first solenoid valve 9 is left in the rest position, the second solenoid valve 10 is activated and the third solenoid valve 11 is left in the rest position.
• the value of the pressure in the ink reserve 1 is between the two rapid regulation thresholds, but outside the interval formed by the two setpoint thresholds.
• the annex reserve 12 When the value of the pressure in the ink reserve 1 is less than the minimum threshold pressure pressure value, the annex reserve 12 is charged with gas under pressure and this volume is immediately transferred to the ink reserve, these operations being repeated as many times as necessary so that the value of the pressure in the ink reserve 1 becomes greater than the minimum set point pressure value.
• the second solenoid valve 10 is left in the rest position, the third solenoid valve 11 is activated, while the first solenoid valve 9 begins to crackle, that is to say that it activates and deactivates sequentially. , as long as the minimum set point is not reached. This crackling stops as soon as the minimum setpoint threshold is exceeded, and resumes as soon as the pressure in the ink reserve 1 falls below this same threshold. Likewise, when the value of the pressure in the ink reserve 1 is greater than the maximum set pressure threshold value, the crackling of the first solenoid valve 9 makes it possible to reduce and maintain the pressure in the ink reserve 1 below the maximum setpoint threshold, this time leaving the third solenoid valve 11 in the rest position so as to charge the annex reserve 12 with vacuum gas.
• the device is here applied to regulating a vacuum in the reserve 1 so as to keep the liquid 3 inside of it.
• a positive pressure is similarly regulated to allow the reserve 1 to be purged of the liquid that it contains. For example, by selecting a minimum setpoint pressure pressure value of 25,000 Pa (0.25 Bar) and a maximum setpoint pressure pressure value of 35,000 Pa (0.35 Bar).
• FIG. 3 shows an application of the vacuum device to the manufacture of intelligent portable objects such as smart cards, CDs, CD-ROMs.
• the manufacturing installation 17 comprises a conveyor 19 moving the intelligent portable objects 18 from one manufacturing station to another, along the production line.
• Station 16 is an inkjet type printing machine here providing graphic personalization of objects 18, this machine being provided with at least one head 20 in which the ink is maintained by a controlled vacuum using a device and a method according to the invention.

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• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• Automation & Control Theory (AREA)
• Ink Jet (AREA)
• Control Of Fluid Pressure (AREA)
• Nozzles (AREA)

Applications Claiming Priority (3)

Publications (1)

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ID=8865773

Family Applications (1)

Country Status (6)

Families Citing this family (260)

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• 2001
  • 2001-07-20 FR FR0109756A patent/FR2827682B1/fr not_active Expired - Fee Related
• 2002
  • 2002-07-19 US US10/484,310 patent/US7264327B2/en not_active Expired - Fee Related
  • 2002-07-19 WO PCT/FR2002/002580 patent/WO2003010615A2/fr not_active Ceased
  • 2002-07-19 EP EP02790202A patent/EP1425643A2/de not_active Withdrawn
  • 2002-07-19 CN CN02818418.1A patent/CN100511066C/zh not_active Expired - Fee Related
  • 2002-07-19 JP JP2003515926A patent/JP4830167B2/ja not_active Expired - Fee Related
• 2009
  • 2009-05-01 JP JP2009111906A patent/JP2009196369A/ja active Pending

Non-Patent Citations (1)

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