WO1998017478A1 - Commande de pompe pour imprimante a jet d'encre continu - Google Patents

Commande de pompe pour imprimante a jet d'encre continu Download PDF

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Publication number
WO1998017478A1
WO1998017478A1 PCT/GB1997/002852 GB9702852W WO9817478A1 WO 1998017478 A1 WO1998017478 A1 WO 1998017478A1 GB 9702852 W GB9702852 W GB 9702852W WO 9817478 A1 WO9817478 A1 WO 9817478A1
Authority
WO
WIPO (PCT)
Prior art keywords
ink
print head
reservoir
restriction
orifice
Prior art date
Application number
PCT/GB1997/002852
Other languages
English (en)
Inventor
James P. Mckee
Original Assignee
Domino Printing Sciences Plc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Domino Printing Sciences Plc filed Critical Domino Printing Sciences Plc
Publication of WO1998017478A1 publication Critical patent/WO1998017478A1/fr

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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
    • 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
    • B41J2/18—Ink recirculation systems

Definitions

  • the present invention relates to continuous ink jet (CIJ) printers and, more particularly, to an apparatus for controlling ink flow within such printers.
  • CIJ continuous ink jet
  • ink is pumped continuously through one or more nozzles, the stream of ink passing through the or each nozzle being broken up into individual droplets under the action of a piezoelectric or similar oscillator and the droplets being selectively charged and deflected in an electric field for printing purposes, non- printable droplets passing into a gutter from which the ink is returned to a reservoir feeding the pump.
  • pumps may be used.
  • the motor drives the pumps therefore together and each of the pumps is optimised for its particular use.
  • a pressure regulator may be used to adjust the pressure of ink supplied to the print head or pump speed may be controlled.
  • the pumps are gear pumps, with different pump gears being used for the supply and gutter-return flows.
  • the flow rates of the supply and return will vary from application to application.
  • the flow of ink required at the print head is, for a given application, effectively, constant, but the return flow through the gutter may be variable or may require greater air flow.
  • the motor requires to be driven at a substantially constant speed to provide a uniform supply of ink to the print head whereas, on the other hand, there is, preferably, a requirement for variable speed depending upon operating variables such as print head elevation, ink supply conduit length, gutter return tube diameter, ink viscosity, ink surface tension, number of nozzles (in the case where a different print head containing a different number of nozzles may be installed or perhaps a different nozzle may be installed in the same print head) , etc.. These conditions appear to be mutually exclusive.
  • the motor can be operated at a speed which corresponds with the maximum required gutter flow rate for the printer. This, of course, is wasteful and may result in the entrainment of considerable volumes of air within the ink returned from the gutter, in turn causing additional problems such as high ink solvent consumption, increased power requirements, etc.
  • a continuous ink jet printer incorporating two pumps, one for ink supply and one for return vacuum, driven by a single variable speed motor, and a reservoir from which ink is drawn by the supply pump and to which ink is returned by the return pump; includes an orifice or restriction connected between the reservoir and the ink supply downstream of the supply pump.
  • the orifice or restriction which may be fixed or variable in size, is used to bleed ink flow from the supply pump side back to the reservoir. Since the print head flow requirement is substantially constant, establishing the bleed flow rate with the orifice or restriction permits speed adjustment to enable adjustment of the return pump flow for controlling gutter flow, without compromising the required supply flow to the print head.
  • the dual-circuit pump motor will normally be driven to the speed necessary to provide the required flow of ink to the print head nozzle or nozzles, and the orifice or restriction can be adjusted in size or else, if it is of fixed size, it can be selected based on the orifice or restriction size which will provide the required gutter flow.
  • the orifice or restriction is variable in size and the effective flow area is increased, or if a larger flow fixed orifice or restriction is installed, the increased size of the orifice or restriction provides a greater by- pass flow to the reservoir resulting in an increase in motor speed in order to maintain the print head flow, thereby resulting in an increase in gutter flow through the return pump. Conversely, if the orifice or restriction size is reduced or a smaller orifice or restriction installed, reduced by-pass flow results, in turn causing the motor to decrease in speed to maintain the print head flow and resulting in a decrease in the return flow from the gutter.
  • the orifice or restriction may be opened or closed, for example by means of a valve such as a solenoid valve, in order to achieve similar changes in speed of the pump motor in order to maintain the supply flow to the print head whilst changing the return flow from the gutter.
  • the orifice or restriction may be automatically adjusted using a rotary, spool, or similar valve or a rotary actuator on a needle or metering valve providing a variable restriction, to adjust the pump speed/gutter flow rate based on a gutter flow parameter (eg vacuum) , adjustment taking place while ink is being pumped to the print head to generate flow to the gutter, but during periods of non-printing.
  • a gutter flow parameter eg vacuum
  • Figure 1 is a diagram of an ink circuit for a multi- nozzle CIJ printer
  • Figure 2 is a diagram of an alternative ink circuit for a multi-nozzle CIJ printer, and;
  • Figure 3 is a diagram of another alternative ink circuit for a multi-nozzle CIJ printer.
  • an ink circuit has an ink reservoir R from which ink is pumped by means of a supply pump SP and to which ink is returned by a return vacuum pump RP, both of which are driven by the same variable speed motor M via a common drive shaft.
  • the supply pump SP supplies ink to the print head P through a supply line SL via filters Fl and F5, and a solenoid valve SV8 and filter F6 located in the print head P.
  • Diagrammatically illustrated in the print head P is an ink chamber C from which plural individual streams of ink IS are emitted in use through a corresponding plurality of nozzles (not shown) .
  • the ink streams are broken up into droplets by an ultrasonic vibrator (not shown) and droplets which are not required to be printed are directed into a gutter G from which ink is returned through a return line RL via a solenoid valve SV3 and filters F2 and F4 under the action of the vacuum return pump RP.
  • Solenoid operated valves SV1 and SV2 allow ink and solvent make-up respectively into the circuit as required during operation. This is conventional and, as it does not relate to the inventive aspect of the circuit, will not be further described.
  • Solvent can also be fed to the print head through solenoid valve SV7 for flushing at shut down of the printer.
  • the pressure of ink is monitored, in this example, at the print head P by a transducer T6 (or, alternatively ink jet velocity is monitored) and information from the transducer is fed back to the variable speed motor M in order to achieve a substantially fixed pressure supply of ink or fixed jet velocity to the print head P.
  • the required pressure will depend upon the ink being used which in turn will vary from application to application and, similarly, the amount of ink returned depends upon the application (eg. different nozzles and other parameters mentioned above) and therefore the ratios of the flows produced by the supply pump SP and the vacuum return pump RP will vary from application to application.
  • a flow control restriction FCl is provided between the supply line SL and the reservoir R in a by-pass line BL, the flow control restriction FCl being sized appropriately or adjustable in order to produce the desired flow ratio between the supply pump SP and the vacuum return pump RP for the given application.
  • the flow control restriction FCl is shown as fixed in size and is preferably readily changeable in order to enable the printer to operate under varying flow rate conditions, for example for use with different inks or different nozzles.
  • the flow control restriction FCl may be variable and capable of adjustment to accommodate different flow rates which may be required.
  • a temperature sensor T10 for measuring the temperature of the ink and, in parallel with the by-pass line BL and controlled through a solenoid valve SV13 , there is an ink sampling line ISL having a viscometer VM1 for measuring the viscosity of the ink.
  • a pressure release valve PRV1 is also provided to allow flow through the by-pass line BL to the reservoir R. Measurements of viscosity enable control of the addition of solvent to the ink, via the solenoid operated valve SV2 , to maintain the desired viscosity.
  • Control lines Cl and C2 are connected to the supply line SL via solenoid valves SV12 and SV5 respectively and to the by-pass line BL via solenoid valves SV11 and SV4 respectively to control ink actuated movement of the gutter G and charge electrodes (not shown) in the print head.
  • a further flow control orifice FC2 is provided in the print head bleed line PBL for limiting the return flow of ink from the print head during bleeding of air from the print head when the printer is shut down.
  • the return line RL is connected to the print head bleed line PBL via solenoid valve sv2 , sv7 & SV10. This allows flushing of the print head P with solvent or make-up fluid during shutdown in the manner described in our British Patent Application no. 9719705.7.
  • the circuit shown in figure 3 is similar to that shown in figure 2, but an additional supply pump SP ' and return pump RP' are provided, along with motor M 1 .
  • the supply pump SP • is connected to the reservoir R and via an additional supply line SL' to the supply line SL.
  • the return pump RP ' is connected to the reservoir R and via the return line RL' to the gutter G.
  • the pumps SP ' and RP ' operate in parallel in the ink circuit to the supply pump SP and return pump RP respectively. This arrangement increases the overall pumping power of the system, enabling the use of larger print heads.
  • the circuit shown in figure 2 further includes a reservoir bleed line RBL between the reservoir R and the bleed line BL.
  • the two pump circuit of figure 3 has two reservoir bleed lines RBL and RBL' .
  • the orifice FC3 (and FC4) allows control of the ink flow from the reservoir R to the return line RL (and RL') so that the return pump R (and R') can be "wetted" on start up.

Landscapes

  • Ink Jet (AREA)

Abstract

Cette invention a trait à une imprimante à jet d'encre continu dotée d'une réservoir à encre (R) et d'une tête d'impression (P). Un circuit d'encre qui permet au réservoir de communiquer avec la tête d'impression comprend deux pompes (SP et RP). La première, (SP), est une pompe d'alimentation en encre qui achemine l'encre depuis le réservoir jusqu'à la tête d'impression. La seconde, (RP), est une pompe de retour qui retourne l'encre non utilisé depuis la tête d'impression jusqu'au réservoir. Un seul moteur à vitesse variable (M) commande les deux pompes. Entre la pompe d'alimentation et la tête d'impression, un orifice ou un étranglement (FC1) communique d'un côté avec le réservoir (R) et de l'autre avec le conduit d'alimentation en encre (SL) de sorte que l'encre puisse revenir au réservoir pendant l'impression depuis le conduit d'alimentation en passant par l'orifice ou étranglement (FC1).
PCT/GB1997/002852 1996-10-23 1997-10-16 Commande de pompe pour imprimante a jet d'encre continu WO1998017478A1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US2884396P 1996-10-23 1996-10-23
US60/028,843 1996-10-23

Publications (1)

Publication Number Publication Date
WO1998017478A1 true WO1998017478A1 (fr) 1998-04-30

Family

ID=21845774

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/GB1997/002852 WO1998017478A1 (fr) 1996-10-23 1997-10-16 Commande de pompe pour imprimante a jet d'encre continu

Country Status (1)

Country Link
WO (1) WO1998017478A1 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999062717A1 (fr) * 1998-05-29 1999-12-09 Willett International Limited Imprimante a jet d'encre et procede de fonctionnement
GB2455775A (en) * 2007-12-21 2009-06-24 Linx Printing Tech Inkjet printer having flow restriction system
US20190283438A1 (en) * 2016-07-14 2019-09-19 Domino Uk Limited Improvements in or relating to continuous inkjet printers
EP3817923A4 (fr) * 2018-07-08 2022-02-23 Hewlett-Packard Development Company, L.P. Distribution de liquide dans un distributeur de type à jet d'encre

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2828998A1 (de) * 1978-07-01 1980-01-03 Staedtler Fa J S Verfahren und vorrichtung zur steuerung des schreibmittelzulaufs zur schreibeinrichtung mechanischer schreiber
WO1985001696A1 (fr) * 1983-10-13 1985-04-25 Imaje S.A. Circuit d'alimentation en encre d'une tete d'impression a jet d'encre
EP0142264A1 (fr) * 1983-10-19 1985-05-22 Domino Printing Sciences Limited Systèmes hydrauliques pour imprimantes à jet d'encre
US4614948A (en) * 1985-04-12 1986-09-30 Eastman Kodak Company Ink circulation system for continuous ink jet printing apparatus
US4714931A (en) * 1985-12-16 1987-12-22 Domino Printing Sciences Plc. Ink jet printing system

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2828998A1 (de) * 1978-07-01 1980-01-03 Staedtler Fa J S Verfahren und vorrichtung zur steuerung des schreibmittelzulaufs zur schreibeinrichtung mechanischer schreiber
WO1985001696A1 (fr) * 1983-10-13 1985-04-25 Imaje S.A. Circuit d'alimentation en encre d'une tete d'impression a jet d'encre
EP0142264A1 (fr) * 1983-10-19 1985-05-22 Domino Printing Sciences Limited Systèmes hydrauliques pour imprimantes à jet d'encre
US4614948A (en) * 1985-04-12 1986-09-30 Eastman Kodak Company Ink circulation system for continuous ink jet printing apparatus
US4714931A (en) * 1985-12-16 1987-12-22 Domino Printing Sciences Plc. Ink jet printing system

Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999062717A1 (fr) * 1998-05-29 1999-12-09 Willett International Limited Imprimante a jet d'encre et procede de fonctionnement
GB2455775A (en) * 2007-12-21 2009-06-24 Linx Printing Tech Inkjet printer having flow restriction system
GB2455775B (en) * 2007-12-21 2012-07-18 Linx Printing Tech Inkjet printer and flow restriction system therefor
US8517485B2 (en) 2007-12-21 2013-08-27 Linx Printing Technologies Ltd. Inkjet printer and flow restriction system therefor
US20190283438A1 (en) * 2016-07-14 2019-09-19 Domino Uk Limited Improvements in or relating to continuous inkjet printers
US10906324B2 (en) * 2016-07-14 2021-02-02 Domino Uk Limited Continuous inkjet printers
EP3817923A4 (fr) * 2018-07-08 2022-02-23 Hewlett-Packard Development Company, L.P. Distribution de liquide dans un distributeur de type à jet d'encre
US11440330B2 (en) 2018-07-08 2022-09-13 Hewlett-Packard Development Company, L.P. Liquid delivery in an inkjet type dispenser

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