FR2484289A1 - SEQUENTIAL DROPLET CHARGE SYSTEM APPLICABLE TO MULTI-BUTTON PRINTERS - Google Patents

Abstract

THE INVENTION RELATES TO A SYSTEM FOR SEQUENTIAL DROP LOADING. SUCH A SYSTEM CONTAINS AT LEAST ONE ROW OF NOZZLES 1 IN LINE ASSOCIATED WITH MEANS FOR SUCCESSIVE NOZZLES TO EMIT THEIR DROPS ONE AFTER ANOTHER, A SINGLE ELECTRODE 3 FOR THE SEQUENTIAL CHARGE OF THESE DROPS, A DEVIATION DEVICE 4 , 5 LOADED DROPS. THE INVENTION APPLIES IN PARTICULAR TO MULTI-NOZZLE INKJET PRINTERS.

Description

The present invention relates to a sequential charging system

  A number of droplets are applicable to multi-bus printers of the type in which the droplets that form are electrostatically charged or not and then pass into a device that deflects the droplets according to their electrical charge.

  In particular, drop-jet printers are known, in particular

  plates having a plate in which are arranged a plurality of nozzles arranged in at least one line, these nozzles being

supplied with liquid.

  Means for applying mechanical vibrations to the plate are provided so as to simultaneously cause the formation of drops for all liquid jets from the nozzles. Each nozzle is associated with a selective charging electrode of the drops 9, which then pass into a device for deflecting the charged drops. The deviated drops are intercepted and recovered while the non-deflected, that is, uncharged drops, continue to flow. way to reach the support to score. Such a device has the disadvantage of requiring a large number of electrodes

  load since one is needed per nozzle.

  The present invention makes it possible to produce a printer of this type that does not have this drawback. Indeed, only one

  electrode is required for the charge of the drops.

  According to the invention, the charging system comprises at least one row of nozzles in line associated with means for the successive nozzles to emit one after another their droplets, a single electrode for the successive charge of these droplets, a

  device for deflecting charged droplets.

  According to one embodiment of the invention, each nozzle may be associated with an excitation member capable of causing the formation of drops, the successive excitation members being controlled one after the other. These are, for example, pressure wave generators in the liquid supplying the nozzles (such as piezoelectric generators); the line of organs cPexcitation can

  be associated with a delay line (or shift register)

  to introduce a phase shift between the successive excitation

  sifs and so to submit Pune after another the nozzles to an excitation. An advantage of the system is that the basic device can be

combined in different ways.

  Thus the row of nozzles can be arranged parallel to the direction of travel of the medium to be marked and be associated with means to generally give it a transverse scanning movement. This movement can be perpendicular to the direction of travel of the support, with step advance thereof. This movement can also be 8-shaped, with uniform advance of

  support and marking with the forward scan and the reverse scan.

  The row of nozzles can also be arranged perpendicularly

  stretching in the direction of scrolling the support to be marked and associated with means to generally give it a transverse movement

  of amplitude scanning close to the pitch of the nozzles. As above

  this movement can be perpendicular to the sense of

  scrolling the support or shaped 8.

  The printer may also have several rows of nozzles associated in line or matrix. These various organizations can meet a threefold objective: the increase of the print rate performances, the ease of adaptation of the marking pitch with respect to the juxtaposition of the nozzles,

  minimizing the complexity of the control circuits.

  Thus, the printer may have several rows identi-

  of nozzles, arranged on the same line, this line being oriented transversely to the direction of travel of the medium to be marked. In the case where an electric droplet emission control is associated with each nozzle, the homologous systems can be controlled simultaneously and in parallel.

different rows.

  A matrix organization of the rows may also be provided. In this case, the printer comprises the side-by-side association of several lines with several rows, the different lines being chosen so as to artificially reduce the not apparent juxtaposition of the nozzles. As before, the electrical controls of the homogenous nozzles can be paralleled.

  logues for all rows.

  The description which follows, with reference to the attached drawings

  given as a non-restrictive example

  the invention can be realized.

  FIG. 1 is a schematic sectional view of a mode of

  production of a printer made according to a known technique.

  FIG. 2 is a sectional view taken along line IMI1 of FIG.

figure 1.

  FIG. 3 is a schematic sectional view of a mode of

  production of a printer made according to the invention.

  FIG. 4 is a sectional view, taken along line IV.IV of FIG.

Figure 3.

  FIG. 5 is a sectional view of an exemplary embodiment

  of a droplet generator according to the invention.

  FIG. 6 represents a variant embodiment of the line

  of piezoelectric excitation of the droplet generator.

  Figures 7, 8, 9, 11 are schematic views showing

  various arrangements of nozzle rows.

  FIG. 10 is an explanatory diagram concerning a variant

realization of the movement in 8.

  Figures 1 and 2 illustrate schematically a mode of

  production of a droplet jet printer (mentioned above).

  demment) performed according to a known technique.

  A plurality of nozzles 1 is formed in a line in a plate 2 bathed on one side by a pressurized liquid, ink E, by

example.

  Next to each nozzle is a charging electrode

  3 ensuring selective loading of drops from the nozzle.

  For the formation of drops of the means (not shown)

  to apply mechanical vibrations to the plate are provided.

  Thus, the ink comes out of the nozzles 1 in the form of jets 6 and the vibrations cause the simultaneous formation of droplets 7 of

  essentially uniform dimension by the jets 6.

  The drops are loaded or not by the charging electrodes 3a at the time of their formation and then pass between two

  deflection electrodes 4, 5 between which a difference is

  substantially constant potential.

  The charged drops are deflected by the electro-

  static and intercepted by the ink fountain 8 associated with the electrode 5.

  The recovered ink is returned to the ink tank.

  The uncharged drops pass between the two electrodes 4, and strike the support to mark 9, a sheet of paper

  or tissue for example, which moves with regard to the printer.

  In this embodiment there are as many electrode electrodes

load 3a there are nozzles 1.

  Figures 3 and 4 schematically illustrate an embodiment of a droplet jet printer using a

  sequential droplet charging system realized with the nven-

tion.

  We find the plate 2 provided with its nozzles 1 in line, the

  deflector electrodes 4, 5 with the ink fountain 8, the support to be marked 9.

  On the other hand, only one charging electrode 3 arranged opposite

  of the entire nozzle line 1 is provided.

  The successive nozzles emit one after the other their

  by means not shown in FIGS. 3 and 4. These means can be, for example, those illustrated

in Figures 5 and 6.

  The charging electrode 3 can be controlled to ensure succes-

  the selective loading of all droplets. This

  load can optionally be amplitude modulated.

  Such an embodiment has the advantage of not requiring

  only one charging electrode.

  Figures 5 and 6 illustrate an embodiment of a

  droplet generator requiring only one charging electrode.

age 3 associated.

  The plate 2 is part of a chamber or collector 21 fed with liquid E under pressure. Opposite each nozzle 1, the chamber has an opening into which is introduced a piezoelectric ceramic transducer 22 which can periodically generate pressure waves in the liquid. The line of the piezoelectric transducers 22 is associated with a delay line or electric shift register 23 providing a delay between the impulsions sent to the successive transducers 2 will send one after the other a pressure wave to the nozzle associated with them. Consequently, the successive nozzles 1 will generate one after another drop 7 and a single electrode) (as illustrated in FIGS. 3 and 4) can process all the drops separately. This embodiment can be used in the printer of FIGS.

Figures 3 and 4.

  Figure 6 illustrates an embodiment of the line

  of piezoelectric excitation by means of a ceramic strip 24.

  on which are deposited independent electrodes 25.

  Another way that the use of a delay line 23

  could be implemented to control the piezoelectric transducers

  22 without departing from the scope of the invention. Each transducer

  22 can be controlled individually.

  One advantage of the system is that the basic device described in the previous embodiments can be combined with

different ways.

  First of all this device can be associated with means for

  globally give it a transverse scanning movement.

  Thus, in FIGS. 7 and 8, it is possible to see a basic device with a row of nozzles arranged parallel to the direction of

  scrolling the support to be marked 41.

  This device 40 can be associated with means (not shown

  felt) to globally give him a movement perpendicular to the direction S (according to the arrows FI), with step advance of the support 41

(see Figure 7).

  The movement can also be in the form of 8 (according to F2, FIG. 8), with uniform advance of the support 41. In order to give the device 40 the desired movement, it is possible to use, in a known manner, cams synchronized with Flag of the support to mark. The base device 40 may also, as illustrated in FIG. 9, be arranged perpendicularly to the direction of movement S and animated by a transverse movement of amplitude close to the pitch of the nozzles. As before, the movement can be rectilinear with stepwise advance of the support 41 or in the form of 8 according to F3 and uniform advance of the

support 41.

  To achieve the movement in 8, we can combine a

  mechanical movement of the device 40 in a direction x perpendicular

  dicular in the direction of scroll S and electrostatic deflection of the drops in the y direction parallel to x (Figure 10). This variable deflection of the drops can be obtained by the modulation

  amplitude of the droplet charge (as indicated above).

ously).

  The printer may also have several rows of nozzles associated in line or matrix. Thus, in FIG. 11, on the left we can see two basic devices 40 with a row juxtaposed on the

  same line, this line being oriented perpendicular to the direction.

scrolling on the support 41.

  The droplet emission sequences are synchronous for the different rows of nozzles. This allows, in the case where an electrical control is associated with each transmission nozzle, simultaneously and in parallel control the peer systems

different rows.

  Each device 40 retains its elec-

  trostatic 3 clean. By way of example, an assembly consisting of 10 rows of each 10 nozzles supplied with droplets on demand by a piezoelectric system will require: - 10 different electrostatic controls (1 control per device 40), - 10 electrical excitations of piezoelectric elements, the first of these excitations acting on behalf of the first nozzle of each of the ten devices 40, etc. This system therefore comprises 20 control circuits for 100

controlled nozzles.

  On the right side of Figure 11, we can see an organization

  Matrix layout of the nozzle rows. This organization corresponds to

  to the association side by side of several rows of bars. Two devices 400 are shown, each comprising 4 rows of

  nozzles. The homologous rows of each device 400 are available

  on the same line. On the other hand, the rows of the same device 400 are arranged in quinconque so as to reduce the pitch

  1.5 apparent juxtaposition of nozzles. -

  For example, if one associates 4 rows of each 10 bars of 10 nozzles, one constitutes a set of 400 nozzles for which one can proceed as previously to the paralleling of the electric controls of the homologous nozzles for the whole rows, which leads to control all 400 nozzles with

only 80 control circuits.

Claims (7)

  1. Sequential charge system of droplets of the type in which the droplets that form are or are not charged   electrostatic and then go into a device that deflects   according to their electric charge, characterized in that it comprises: - at least one row of nozzles (1) in line associated with means for the successive nozzles to emit their droplets one after the other, - a single electrode (3) for the successive charging of these droplets,   - A deflection device (4, 5) charged droplets.   2. System according to claim 1, characterized in that each nozzle is associated with an excitation member adapted to cause the formation of drops, the successive excitation members being   ordered one after the other.   3. System according to claim 2, characterized in that the excitation members are pressure wave generators in the liquid supplying the nozzles.   4. System according to claim 2 or 3, characterized in that the line of excitation members is associated with a delay line (2, 3) for introducing a phase difference between the excitation members.   successive and so to submit Pune after another the nozzles to one. excitation. -   5. System according to any one of the preceding claims   characterized in that the row of nozzles (1) is arranged parallel or perpendicular to the running direction of the support to be marked (9) and is associated with means for giving it   overall a transverse movement of scanning.   6. System according to claim 5, characterized in that the transverse movement is perpendicular to the direction of travel of the support (9) and that it is associated with means of advance step by step. 7. System according to claim 5, characterized in that the transverse movement follows a path in the form of 8 while the support to be marked (9) is associated with means cdavance uniformo   System according to any one of claims i to 4e   characterized in that it comprises several identical rows of juxtaposed juxtaposed nozzles on a same line, this line being oriented transversely with respect to the direction of travel of the medium to be marked (9), said means for the successive nozzles of a row to emit one after the other, their droplets being comi   simultaneously and in parallel.   System according to claim 8, characterized in that it comprises the side-by-side association of several lines with several rows, the different lines being arranged in such a way as to artificially reduce the apparent pitch of association of the nozzles,   10. System according to any one of the preceding claims   dentes, characterized in that the charge of the droplets is amplitude modulated so as to obtain a variable deflection of the drops. 1. System according to claim 10, characterized in that a row is associated with moving means in one direction.   perpendicular to the direction of deflection of the drops.