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
  • B41J2/18—Ink recirculation systems
  • B41J2/185—Ink-collectors; Ink-catchers
• • 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
  • B41J2/07—Ink jet characterised by jet control
  • B41J2/075—Ink jet characterised by jet control for many-valued deflection
  • B41J2/08—Ink jet characterised by jet control for many-valued deflection charge-control type
  • B41J2/09—Deflection means
• • 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
  • B41J2/185—Ink-collectors; Ink-catchers
  • B41J2002/1853—Ink-collectors; Ink-catchers ink collectors for continuous Inkjet printers, e.g. gutters, mist suction means

Definitions

• the invention relates to an ink jet print head; it relates more particularly to its applications to industrial tracers.
• the latter come in various forms, but are all composed of a part supporting the sheets (supports) to be traced, of another part supporting one or more styli, these two parts being set in relative movement, either by displacement of the sheets, either by moving the styli, or by a combination of the two methods.
• the pens depositing the ink are often either ballpoint pens, or felt tips, or hollow tips with special inks of the Chinese ink type.
• a difficulty also arises in terms of the compatibility between the ink, the technology of the stylus, and the quality of the support to be printed which is not obvious, which has the consequence of greatly limiting the quality and duration of life of the track on its support.
• a different type of stylus should be used (ballpoint pens, felt tips, hollow tubes, etc.).
• the object of the invention makes it possible to avoid all of the drawbacks listed above, by proposing an alternative solution to existing styli, by a continuous inkjet print head, adapted to the needs of the industrial layout. .
• the invention relates more precisely to a continuous ink jet print head associated with an ink circulation system, comprising a recovery gutter, this head essentially consisting of a modulation system, a nozzle for ejection, of the drop charge electrodes, of a deflection system, characterized in that this deflection system comprises a set of deflection plates arranged and supplied by means of an electronic circuit so that the electric field ( E) of drop deflection is adjustable at an angle which can vary from 0 ° to 180 °.
• E electric field
• FIG. 2 is an illustration of variable line thicknesses which can be obtained by the inkjet technique
• FIG. 3a and Figure 3b schematically and respectively illustrate a print head according to the invention - front view, and the deflection plates of said head seen from above;
• FIG. 5 shows a plot on a support with orientations of the frame of different points
• - Figure 6 illustrates the corrected head-support relative trajectory, as a function of the radius of rotation of the dot grid
• - Figures 7a and 7b respectively illustrate a front view of a second alternative embodiment of a print head according to the invention and, seen from above, the combination of the set of deflection plates cooperating with a recovery gutter with configuration adapted;
• - Figure 8 illustrates the path of the drops in this second variant
• - Figures 9a, 9b, 9c and 9d illustrate the operation of the deflection plates of this second variant
• FIG. 11 illustrates a third alternative embodiment of a set of deflection plates according to the invention.
• FIG. 13 and 14 are diagrams illustrating the control parameters of these voltages.
• Figure 1 is a figure of the known art which illustrates the inkjet printing technique concerned.
• This consists of producing a continuous jet of calibrated drops (I) supplied by a modulation system (8) connected to an ink supply device (80). At the level of the break of the jet leaving the ejection nozzle (81), the drops are electrostatically charged by means of charging electrodes (7). Deflection plates (35) creating an electric field deflect them from their trajectory. All of these modulation, ejection, load and deflection means constitute the print head (T). If the support (S) on which one wishes to write and the print head (T) are in relative movement, one obtains the formation of a printing matrix. In the example described, it is an "M". All unused drops are collected in a gutter (1) before being recycled into the ink circulation system (2).
• Lines of thickness e 0.1; 0.2; 0.3; 0.4; 0.5 were represented. They are respectively composed of a number of drops (nb) varying from 1 to 5 creating on the support an impact of the order of lSO ⁇ ⁇ tm in diameter.
• This description therefore shows the advantage of replacing the marking members generally used in industrial marking machines with an ink jet print head; this is an application indisputably interesting from the inkjet technique to the field of industrial tracing.
• the present invention also relates to a new print head particularly suitable for this application as is now described. It turns out that, in the conventional inkjet technique, and as illustrated by means of FIG. 1, the jet prints columns of dots. On an industrial layout machine, the support can move in all directions relative to the stylus. However, in the known technique of the deflected continuous jet, printing columns of dots (screens), these are always located in the same plane which is, in general, perpendicular to the direction of movement of the object to be marked (see Figure 1 ).
• One of the important characteristics of the invention therefore resides in the fact that, thanks to a new arrangement of the deflection plates, an orientable electric field of deflection of the drops is obtained. Under these conditions, it becomes possible to maintain the column of points (1 to 5 points in the example of Figure 2), composed of a set of deflected drops (weft) in a plane always perpendicular to the direction of relative movement of the media to print and whatever it is.
• An electronic control circuit cooperates with this new set of deflection plates according to the invention, a circuit which will be described later.
• an adaptation of the shape of the gutter contributes to the success of the process.
• FIG. 3a A first alternative embodiment of a printing head according to the invention is shown, seen from above, in FIG. 3a while FIG. 3b illustrates the new set of deflection plates for this head, seen from above.
• modulation body (8) receiving the pressurized ink comprising an ink ejection nozzle forming the ink jet, a drop charge electrode associated with a detector (6) for passing the drops, a gutter (1) for recovering the ink drops not used for printing, associated with a recovery line (2) for the ink placed under vacuum (arrow f).
• this print head comprises a combination of three deflection plates (3,4,5) in order to create an electric field of deflection of the charged drops ?, or ientable from an angle which can vary from 0 ° 180 °.
• Two of these plates (3 ) and (5) are parallel to each other and the third (4) is located in a plane perpendicular to the previous ones.
• this set of three deflection electrodes (3,4,5) cooperates with a particular structure of recovery gutter (1), allowing the orientation of the deflected drops from 0 ° to 180 °.
• the drops fall into a circular orifice (la) made in a narrowed extension (lb) of the flat reservoir forming the gutter (1). This orifice is located in the axis of the head (T).
• Each deflection angle corresponds to an electric field (E) created by combining the high voltage supply from each of the three plates.
• the dot pattern does not fall in the same place.
• FIGS. 7a and 7b A second alternative embodiment of a print head according to the invention is illustrated by means of FIGS. 7a and 7b, of FIG. 8 and of FIGS. 9a, 9b, 9c and 9d.
• FIG. 7a schematically represents the print head seen from the front and FIG. 7b, the set of deflection plates seen from above with the recovery gutter (1) having an original shape and suitable for this application.
• the number of deflection plates is here again equal to three.
• the drops used for printing are, for their part, deflected so that the center of the screen of printed dots, whatever the number, is in the axis of the head, and therefore in the center of the chute.
• (111) semicircular of the gutter (1).
• the example is given in FIG. 8 with a grid of five points, a figure in which only appear the modulation system and the gutter (1) with its semicircular trough (111).
• FIGS. 9a, 9b, 9c and 9d are shown diagrammatically several orientations of the deflection field, respectively 0 °, 45 °, 90 ° and 180 °, with a grid of four points.
• the drops not used for printing are deflected and represented by the white spot (x) in the chute (111) of the recovery gutter (1).
• the advantage of this architecture is the possibility of making a line, with programmable line thickness, by playing on the number of drops, and this while retaining this line thickness whatever the relative trajectory of the head and of the printed medium, without having to use a correction of the relative trajectory of the head relative to the support as was the case in the previous variant ( Figure 6).
• Another advantage of this second variant is that the print head can withstand significant acceleration thanks to at the special disposal of the recovery gutter (1). Indeed, during a phase of acceleration (and deceleration) of the head in the direction of the vector (V solicit) represented in FIG. 10, that is to say perpendicular to the plane of deflection of the drops; these are slightly offset in the axis of the vector (V) ( Figure 10) during their trajectory.
• FIG. 11 illustrates a third alternative embodiment of a print head according to the invention.
• four deflection plates (3,4,5,9) are provided.
• the plate (9) is parallel to the plate
• a control circuit (C) for the high deflection voltages cooperates with a directional deflection printing head according to the invention.
• the control circuit (C) of the high deflection voltages therefore has the role of bringing to the adequate potentials the three electrodes (3), (4) and
• the angle ( fi) of the relative movement of the printed medium pnr with respect to the print head is transmitted to a control device (200).
• These measures control (200) searches at all times in a memory (30) the values of the voltages (Vg, V, V, V) which it is necessary to apply to the electrodes to obtain the orientation of the frame according to the angle û) desired.
• the same circuit (200) continuously controls the devices (201) d r supply voltage of the deflection electrodes. These voltages are characteristic of a given print head. An example of calculation of the values of these voltages is given below.
• the voltages of the deflection electrodes are adjusted so as to create at the level of the drops a resulting electric field (E), of a given intensity, and oriented in the plane perpendicular to the axis of the relative movement of the printed support with respect to the printhead.
• V., V, V, V The calculation of the voltages (V., V, V, V) depends on the geometry of the head considered and strictly requires the resolution of the physical problem of the distribution of the electrical potential in the print head, taking into account the details. geometric head. This resolution can be done by various methods, including digital computer resolution methods. When the position of the drops is centered relative to the electrodes and the size of the electrodes is large compared to that of the frame, one can obtain an approximate value of the deflection voltages necessary to obtain the electric field of value (E) oriented according to the angle ( ⁇ ) desired.
• the value of the resulting field is, under these conditions, equal to 0.25 MV / m. 2.5 Other voltage combinations can be envisaged to obtain this result. These combinations follow from the same equations.
• the ink ejection nozzle has an internal diameter of 25 microns, and the voltages applied to the charging electrode are of the order of 150 volts maximum to obtain the line widths 0 desired (0.1 to 0.4 mm).

Landscapes

• Particle Formation And Scattering Control In Inkjet Printers (AREA)

Applications Claiming Priority (2)

Publications (1)

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ID=9337692

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• 1986
  • 1986-07-21 FR FR8610727A patent/FR2601625B1/fr not_active Expired - Lifetime
• 1987
  • 1987-07-20 AU AU77073/87A patent/AU609410B2/en not_active Ceased
  • 1987-07-20 DE DE8787401856T patent/DE3782710T2/de not_active Expired - Fee Related
  • 1987-07-20 JP JP62504355A patent/JPH01500341A/ja active Pending
  • 1987-07-20 WO PCT/FR1987/000286 patent/WO1988000529A1/fr not_active Application Discontinuation
  • 1987-07-20 EP EP87904699A patent/EP0274507A1/fr active Pending
  • 1987-07-20 EP EP87401856A patent/EP0262004B1/fr not_active Expired - Lifetime
  • 1987-07-20 US US07/180,103 patent/US4905018A/en not_active Expired - Fee Related
  • 1987-07-20 ES ES198787401856T patent/ES2035097T3/es not_active Expired - Lifetime
  • 1987-07-21 CA CA000542580A patent/CA1284743C/fr not_active Expired - Lifetime
• 1992
  • 1992-12-14 GR GR920402897T patent/GR3006523T3/el unknown

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