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
  • B41J2/195—Ink jet characterised by ink handling for monitoring ink quality

Definitions

• INK CIRCUIT IN PARTICULAR FOR PRESSURIZING A PIGMENT INK FOR AN INK JET PRINTER.
• the invention relates to an ink circuit in particular for the set pressure of a pigment ink printer for j 'and ink.
• the object of the invention is to overcome the drawbacks linked to the presence
• the invention relates more precisely to an ink circuit for a continuous ink jet printing device, in particular adapted to the implementation of an ink heavily loaded with pigments to make it opaque and white, circuit
• this viscometer (27) is connected on the one hand by two ink circuits, one (45) to the accumulator tank (6) via a solenoid valve (23), the other (44) to the bottom of the recovery tank (2) via a solenoid valve (21); on the other hand by two
• REPLACEMENT SHEET - Figure 1 is a general diagram illustrating the combination of means used in the ink supply circuit according to the invention
• FIG. 2 is an explanatory diagram of one of the constituent elements of the circuit of Figure 1. For clarity, the same elements have the same references in all the figures.
• the invention relates to a pigment ink circuit, suitable for supplying an ink jet print head, so that all the drawbacks linked to the presence of these pigments in the ink, be avoided.
• the architecture of this circuit and the combination of the means used make it possible, for this particular application, to achieve the three essential functions required for the proper functioning of an inkjet printer, namely:
• a circuit according to the invention a fourth which is a function of permanent agitation of the ink in order to avoid the sedimentation of the pigments in the bottom of the tanks.
• the pressurization of the ink to ensure the jet is carried out by means of an ink accumulator tank (6) which is put under air pressure.
• the generation of compressed air is ensured through a first pressurization circuit by a first head (9) of a compressor (7).
• the air passes through a first filter (8) associated with a silencer, then passes through a second filter, made of .. filter foam, located inside the first head (9) also called pressure.
• the air flow rate of this head is 1.6 m3 / hour at atmospheric pressure.
• a calibrated valve (10) at a threshold value for example 4.2 bars, limits the maximum operating pressure in the circuit.
• the air passing through the pipe (40) then passes through a regulator (11) capable of adjusting the pressure with precision before pressurizing the ink accumulator tank (6) which supplies the print head not shown because being part of known art.
• An arrow (f ⁇ ) diagrams the ink output from the accumulator (6) towards the umbilicus and its print head:
• the pressure setpoint of the regulator (11) is adjusted by adjustment means (111) which can be the combination of a screw and a handwheel for example.
• This pressure is controlled using a pressure gauge (12) mounted through a three-way connection (62) on the pressurization pipe (40).
• the pressurized air enters the storage tank (6) through its upper part.
• the latter consists of a cylinder in which a float (13) slides which has two functions:
• the first is to make a separation between the air (a) under pressure and the ink (e) in order to minimize the migration of air in the ink;
• the second is to allow the detection of the levels in the accumulator tank (6) by means of two proximity detectors (14h) for the high level and (14b) for the low level.
• the storage tank (6) must have a sufficiently large capacity so that the quantity of ink which it contains allows the necessary cooling of the ink contained in the tubes of the navel and in the print head.
• the unused drops are recovered in a gutter not shown as being part of the print head, itself known per se, as has been said previously.
• These recovered drops are brought back to a recovery tank (2) as shown by the arrow (f2), arranged on the recovery pipe (41).
• the recovery tank (2) is placed under vacuum by means of a second vacuum circuit consisting of a second head (15) of the compressor (7) operating as a vacuum pump.
• This vacuum head (15) is identical to the pressure head (9) and its flow / pressure characteristics are the same.
• a safety valve (16) calibrated to a limit value of the tolerable vacuum in the recovery tank (2) and at the outlet of the head (15) a filter associated with a silencer ( 17).
• depression is symbolized by the arrow (f 3).
• the means for pressurizing and vacuuming respectively constituted by the first circuit comprising the general pipe (40) and the second circuit comprising the pipe (42), are distinct from each other and connected to two heads (9) and (15) of a single compressor (7) whose operation ensures the pressurization of the accumulator tank (6) supplying the print head and the partial vacuum of the recovery tank (2), these two pipes (40) and (42) being, moreover, completely - 4bis -
• the ink is indeed highly volatile, so its viscosity must be constantly checked and corrected by adding either ink or solvent.
• a solvent tank (20) and an ink tank (1) are provided, connected to each other, via a filter (50s) and (50e), and through a solenoid valve (18th ) and (18s), at the top of the recovery tank (2) through the pipes (51s) and (51e).
• the two tanks of solvent (20) and ink (1) are at atmospheric pressure.
• the ink tank (1) is connected to the compressed air line (40) (pressurization circuit) through two solenoid valves (24) and (25). It is also connected to the transfer tank (27) by the pipe (47) via the solenoid valve (24).
• a viscometer (27) which is, for example, of the type described in French patent No. 2,353,441 filed by the Applicant. It is a tank in which the ink from the recovery tank (2) passes before being sent to the accumulator tank (6).
• This viscometer (27) is connected by a line (44), via a solenoid valve (21), to the base of said recovery tank (2) and by a line (45) via a solenoid valve (23) to the base of the accumulator tank (6).
• the pressure prevailing in the viscometer (27) depends on the pressure present in the two pipes (46) and (43) connected respectively, via a solenoid valve (22), to the top of the recovery tank (2) and to the pipe (43 ) between the two valves (24) and (25).
• the ink tank (1), the recovery tank (2), and the viscometer (27) are equipped with level detection means (28e), (28a), (28). These are electrodes immersed in the tank at heights corresponding for the ink tank (1) to the minimum level (V) of ink, for the recovery tank with three levels, low (Vji), medium ( V2) and high (V3), finally for the two-level viscometer (V4) and (V5).
• the difference in height between (V4) and (V5) constitutes one of the parameters allowing the measurement of the viscosity, as will now be explained.
• the level measuring means (28) attached to the viscometer (27) consist of. three plunging electrodes, two of which are at the same low level - 5 -
• the level measuring means (28e) attached to the ink tank (1) are constituted by two electrodes determining the level (V).
• the level measurement means (28r) attached to the recovery tank (2) consist of four plunging electrodes determining three levels (Vi), (V 2 ), (V 3 ).
• the solenoid valves (21) and (22) being open, the pressure of the viscometer (27) is in equilibrium with that of the recovery tank (2), the ink flows into the line (44) through a calibrated leak ( 26) and passes into the viscometer (27).
• the time taken for the level to pass from (V4) to (V5) is measured. If this time is greater than a set value, the viscosity of the ink is too high and an addition of solvent is carried out. If this time is less than or equal to this set value, the viscosity of the ink is low or good and nothing will be done. Natural evaporation of the solvent will increase it.
• volume of ink entering the latter escapes through the pressure regulator (11) .
• a volume of buffer ink (volum below the low level (V4) of the viscometer) remains in it, so as to guarantee that at no time can air be sent to the accumulator tank (6), this to give the solenoid valves (23) and (25) time to close after det ection of the low level of the viscometer (27).
• the solenoid valve (24) is then closed and the solenoid valves (21), (22) are again open for refilling the viscometer (27).
• the solvent (20), ink (1) and recovery (2) tanks have a drain opening (100).
• all the ink contained in the accumulator tank (6) is returned to the recovery tank (2), so that the ink is stirred as will be explained below.
• the solenoid valves (23) and (21) are open, and under the effect of the air pressure in the accumulator tank (6), the ink passes into the recovery tank (2).
• the solenoid valve (23) is closed and the solenoid valve (25) open to also empty the viscometer
• the ink in the viscometer pushes the ink towards the recovery tank (2) which is under vacuum.
• the compressor is stopped and the solenoid valves (25) and (24) are open to relax the air in the ink circuit so that the latter does not remain under pressure.
• the printer then stops.
• the solenoid valves (24) and (25) are open for a few seconds, this to put the pressure head (9) of the compressor ( 7) at atmospheric pressure.
• means are provided for continuously agitating the ink. Indeed, in order to maintain good homogeneity thereof, regardless of its duration of use, it is imperative to mix the ink constantly.
• the ink is mixed in the main new ink tank (1) and in the recovery tank (2).
• the means are identical in both cases. It is a magnetic bar (3) covered with polytetrafluoroethylene (PTFE) or polypropylene, cooperating with two magnets
• the turntable (144) consists of a metal plate on which are glued the two permanent magnets as shown in Figure 2. A particular shape shown in this figure has been chosen for the tanks. It is a frustoconical profile (P) which makes it possible to correctly position the bar (3) above the turntable (144).
• the printer remains disconnected from the electrical network for several days, the sedimentation of the ink in the bottom of the tank is inevitable, and, when the machine is switched on, the speed of rotation of the motors (5) is greatly reduced to avoid the magnetic uncoupling of the rod / turntable assembly.

Landscapes

• Engineering & Computer Science (AREA)
• Quality & Reliability (AREA)
• Ink Jet (AREA)
• Inks, Pencil-Leads, Or Crayons (AREA)
• Particle Formation And Scattering Control In Inkjet Printers (AREA)

Applications Claiming Priority (3)

Publications (2)

Family

ID=9386139

Family Applications (1)

Country Status (12)

Families Citing this family (38)

Family Cites Families (8)

• 1989
  • 1989-10-02 FR FR8913060A patent/FR2652540B1/fr not_active Expired - Lifetime
• 1990
  • 1990-09-28 AU AU65150/90A patent/AU635784B2/en not_active Ceased
  • 1990-09-28 AT AT90914741T patent/ATE138608T1/de not_active IP Right Cessation
  • 1990-09-28 ES ES90914741T patent/ES2089032T3/es not_active Expired - Lifetime
  • 1990-09-28 JP JP2513628A patent/JPH04501987A/ja active Pending
  • 1990-09-28 US US07/687,882 patent/US5451987A/en not_active Expired - Fee Related
  • 1990-09-28 KR KR1019910700555A patent/KR0183016B1/ko not_active Expired - Fee Related
  • 1990-09-28 EP EP90914741A patent/EP0447521B1/de not_active Expired - Lifetime
  • 1990-09-28 DK DK90914741.5T patent/DK0447521T3/da active
  • 1990-09-28 DE DE69027200T patent/DE69027200T2/de not_active Expired - Fee Related
  • 1990-09-28 WO PCT/FR1990/000696 patent/WO1991004862A1/fr not_active Ceased
  • 1990-10-01 CA CA002026656A patent/CA2026656C/fr not_active Expired - Fee Related

Non-Patent Citations (1)

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