DE2227056A1 - Inkjet pens - Google Patents

Description

DlPL-INQ. DIETER JANDER

8 MONKS SO (BÖGENHAUSEN) KOLBERGER STRASSE 21 Telephone: 0811/9827 04

PATENT LAWYERS

DR.-INQ. MANFRED BÖNINQ

Delivery address: reply to:

1 BERLIN 33 (DAHLEM) HUTTENWEG 15 Phone: 0311/8324006 Telegrams: Consideration Berlin

b / i ^; >:>; ö de

June 1, 1972

Patent application

of the company
PAILLARD SA
O, Vaud, Suisse

"Inkjet printer"

The invention relates to an inkjet printer with a write head which moves across a recording medium is at which the ink jet under the effect; a hydrostatic pressure, which forms its own convex ink meniscus at the beginning of a nozzle, and an electrical pressure Field is generated which exerts an attraction on the meniscus in the direction of the recording medium.

209851/0882

Postal check account Berlin West 1743 84 Borlinef Bank AC, üepO4it © nka $ se 1

DIPL.-INQ. DIETER JANDEK DK.-INQ. MANFRED BONINQ PATENT LAWYERS

When driving a writing curve, which is described, for example, in the .Gchv.'eir.oi '· Patents ¹ I ¹ XI ; 559 and 451 2Λ2 , the best Ke suit ate are obtained when the pressure in the' l 'inte is stable during the vocal organres and has a'.'erb which shows the formation of a convex meniscus nm tension; de :? Dune 'Tested. ... ¹ The outflow of the l'inte in l'Oru eir.e ^ a very thin stream occurs only when the ei-ieniscus fails to pass an electric field of a certain magnitude.

At the beginning of a writing period, this pressure rises to this V / ert in a very short time from a V / ert which is very small in order to avoid premature discharge. At the end of a writing period, the pressure drops quickly to the rest value so that the nozzle and the Ab1eπkel electrode are not soiled. Experiments have been successful, (ir .: dirtying while the pressure is being created and falling, and that scattering of the ink jet can occur Patent specification; 39'7 729 is described, enables the rapid change of the pressure from the regular pressure to a target pressure and also the rapid decrease of the latter to the resting pressure There are various constructive solutions that make this result possible.

On the other hand, it has been established that the rit; i :: o der Defamation; the nozzle and the deflecting electrociae during this can be reduced over ^ anpsüusbände, v / hen us electrical li'eld in jU: tionist, since then all l'inteiipax'tikei, die leave the nozzle, ground ν / through the electrical ji'eld bundled.

The invention relates to a typewriter in which

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DIPL.-INQ. DIETER JANDER DR.-INQ. MANFRED BONINQ PATENT LAWYERS

The writing head "carries out a valuation in relation to the recording surface. Such a typewriter is described, for example, in the Swiss patents ^ ö4 2.73 and;" V \ ^l 5 QiI'f ' .

nan has l'estfrestellt that trots the Meßnahmen described i'ivitenpartikel can reach the deflection electrodes, and there cause an accumulation of ink, which disturbs the proper JJ ¹ UhTUiIg of the ink jet. The experiment - ^r: ezeißt that the dispersion has its origins in the acceleration periods of the write head, bearing in mind that the accelerations can become very hot in typewriters quickly eg hundred characters per second, write.

The inventive measure, it is possible to solve the problem without reducing the write speed to nuts.

The invention consists in that control elements are provided which act on the elements which cause the formation of the ink jet in such a way that the formation of the jet is prevented at least during the acceleration period of the writing I: o; pf it.

./ Further details of the invention emerge from the drawing. 1 schematically shows an embodiment Sem. '..., of the invention. Fig. 2 is an electrical circuit diagram of a control device for the ink jet, and Fig. ~ J> a diagram from which the different functions during a Schreibz ^ klus yield.

The writing device according to FIG. 1 has a writing head 1, the construction of which corresponds to that of the Swiss patents

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BATH

DIPL..INQ. DIETER JANDER DR.-INQ. MANFRED BONINQ PATENT LAWYERS

451 212, 451 971 or 452 559. He owns a housing 2 which is designed to be rotationally symmetrical and in which the following parts are installed: a nozzle 3 from which an ink jet 4 emerges, an accelerating electrode 5 with a hole for the ink jet and four deflection electrodes. The ink jet 4 is directed onto a paper tape 7. The latter moves in the direction of arrow f1, with the drive from two cylinders 8 and 9, between which the Paper tape 7 is pressed in.

The writing head 1 is parallel to the surface of the paper tape 7 and movable perpendicular to the direction of movement of the tape, the movement of the head being carried out by an assembly which e.g. corresponds to that of the Swiss patent 364. This unit is shown schematically in FIG. 1 shown: It has two wheels 10 and 11 which are connected to one another via a control cable 12 which is attached to the head 1 at 13 and 14 is attached. During the writing process the head is driven in the direction of arrow f2 by a motor moves, which acts on the wheel. 10 with the interposition of an electrical control clutch 16. At the end of a line the clutch 16 releases the wheel 10, and the writing head moves under the action of a return spring 17 into its: Starting position back. The latter is determined by a small magnet 18 on the control cable 12 is attached and cooperates with a stop element 19 which is attached to the chassis of the writing device.

A magnetic breaker 20, for example of the REED type, is located under the path of the magnet 18 at a small distance from the stop element 19.

At the end of the writing process of a line, the motor 15 moves

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DIPL.-INQ. DIETER JANPER DR..INQ. MANFRED BONINQ PATENT LAWYERS

the paper tape 7 further by the distance between two lines, wherein the gears 21, 22, 23 a control clutch 24, a worm 25 and a threaded wheel 26, which is on the axis of the Cylinder 8 sits, are interposed.

A screen 27 is parallel to the line to be written, arranged below the same, in front of the belt 7 and extending over its entire width. He takes at the beginning at the end of a line and between the letters ink, which is deflected by the electrodes 6. One line 28 allows the umbrella to be deflated.

The nozzle 3 is supplied with ink via a flexible line 29 which is connected to an outlet 30 of a pump 31 is, the input 32 of this pump is in communication with a reservoir 33. A bypass line 34 connects the outlet 30 to the inlet 32 of the pump, located in it a control valve 35 which is controlled by an electromagnet. Such a pump with a bypass line is in the Sohrift of the German patent .... (application no * P 21 64 406.4 of December 21, 1971).

An electronic calculating machine is assigned to the writing device. As schematically in fig. 1 shown, this has Calculating machine a keyboard 37 with keys 38 for input certain numbers and keys 39 for entering certain arithmetic operations. Furthermore, a button 40 is provided, with which the voltage can be switched on. The keyboard 37 is connected to a computing element 41, which in turn is in communication with a character generator 42 via a register 43. Such a generator is for example in Swiss patent specification 416,688. This generator acts on the deflection electrodes 6 while

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DIPL..INQ. DlETEK JANDER DR. INQ. MANFKED BDNINQ PATENT LAWYERS

a high voltage generator 44 generates the voltage required to drive the beam between the
To accelerate nozzle ρ and the acceleration electrode 5.
The acceleration electrode 5 is due to Hasse »

A logic unit 45 coordinates all functions during of the company; it is connected to all electrical controls.

A write process is initiated by putting the calculating machine under voltage: the user presses
for this purpose on the key 40, which has the consequence that
the supply devices of the computing unit 41, the generator 42, the logic unit 45 and the voltage generator 44 are switched on. A pool is then built
between the nozzle 3 and the acceleration electrode 5,

The writing process consists of the following principles
Phases together:

I. The user enters a certain number into the arithmetic unit by pressing the corresponding buttons 33 one after the other. He then presses a button 39 which corresponds to the desired arithmetic operation. This will put in register 43-the characters that the writing device is on to the next
Should write line, entered via the arithmetic unit 41 in coded jj'orm.

II, The user releases the button that determines the arithmetic operation again, which has the result that a control signal is sent out which switches the clutch 16 on. Of the
Print head 1 starts moving and is accelerated to its target speed,

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DirL-INQ. DIETER / OTHER DR..INC MANFRED BONINQ PATENT LAWYERS

a locking signal is sent out. It is used to facilitate the passage of the same information from the processing unit 41 sum register 43 xv while writing a line prevent au.

Ul. A control signal is sent out when the write head comes into the area of the first column in which the writing is carried out begins. This control signal initiates the write process and is triggered by the magnet 18 on the REED interrupter 20 passes by.

IV. The first character is transferred from the register to generator 42 and the latter generates signals which are given to the deflecting electrodes 6 to correspond to the ink jet to lead in such a way that it writes the character to be written.

Further characters follow, while the write head the corresponding Crosses columns.

It should be noted that during the successive phases, in which the print head goes crazy, register 43 no longer by the timer of the arithmetic unit 41 (frequency in the order of magnitude of 100 kHz), but by the timer the logic unit 45 is controlled, the frequency much lower, on the order of 1 kHz, and that the register is the advance of the write head synchronized by controlling the motor 15 and the output for the characters of the register.

V. The register 43 sends out a signal which ends the writing as soon as the register is empty. The clutch 16 is uncoupled and the writing head runs back into its starting position under the action of the J ^ eder 17.

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DIPL..INQ. DIETER JANDER DR.-INQ. MANFRED BONINC PATENT LAWYERS

At the same time, the clutch 24 is engaged; it remains indented until the band 7 has moved the distance between two lines is moved on.

VI. The REED breaker 20 when the magnet 18 passes it generates a signal that ends the locking, so that information from the arithmetic unit 41 again can be fed into register 45. ! Also causes the signal, with a certain delay, the locking of the motor 15.

If the arithmetic unit 41 has fed new information into the register 43 during this delay, generate this information in the register 43 a signal which causes the motor is no longer locked and the clutch 16 is engaged.

This happens, for example, when the arithmetic unit causes successive operations that are preceded by a entered program can be controlled, whereby intermediate results are noted. Repeatedly under these conditions the process described: phases III to VI.

The generation and shutdown of the ink jet emerging from the nozzle 3 is controlled via the valve 35 of the logic Unit 45 controlled.

The device, which the generation of the ink jet at the moment in which the nozzle 3 is immobile or a carries out uniform movement, is a part of the logic unit 45. This device controls the generation of the ink jet during two different

209851/0882

DtPL.-INODIETER JANDER DR.-fNQ. MANFRED BONtNQ PATENT LAWYERS

Phases of the write operation: Mr immediately followed by the writing of the next line to the writing of a line, as is the case for program control of the ink jet 35 at will in a very short time (less than 20 msec) from the moment of closure of the valve generates . If, on the other hand, the jet is interrupted for a certain period between the writing of two lines, some evaporation of the solvent of the unit may occur, which causes the time required to generate the ink jet to be increased. The time can be around 25 to 4-0 ms if the interruption is quite long.

An improvement and thus a greater writing speed are now obtained by using the invention generates the ink jet during the following writing phases:

A) Before the start of the movement of the print head, if the User controls the writing line by line.

B) At the end of the writing head acceleration period, when the machine controls the writing of several lines (in this case the writing head starts moving again immediately after it returns to the starting position).

In both cases, according to the invention, the logic unit 4-5 controls the ink jet to the screen 27 during the period the formation and until the generator 4-2 on the deflection electrodes 6 signals to write a character.

The device which controls the generation and shutdown of the ink jet and which is part of the logic unit 4-5 is in! '' Ig. 2 illustrates schematically.

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DtPL-IN (J. DfETER JANDER DR.-INQ. MANFRED BDNINQ PATENT LAWYERS

This device receives information from the logic unit 4-5 via four inputs:

The input E1 is with the control unit for the motor 15 connected · The logical level at this input is Hull, when the engine is not powered, and 1 when the engine is running.

The input E2 is connected to the interlocking circuit. The logic level at this input is 1 if the input of register 4-3 for information that is sent by the processing unit 4-1 come, open isi;, and 0 when this input is closed and the register is under the control of the logic unit 4-5 timer.

The input E5 is connected to the control circuit of the clutch 16. The logic level of this input is 1 when the clutch 16 is not engaged and 0 when the clutch is engaged is engaged and when the writing head 1 is moved by the motor 15 as a result.

The input E4- is connected to a circle that during the Phases III and IY generates a logic level 0, and which generates a logic level 1 during the remaining phases. The transition from 1 to 0 is effected during phase III by the magnet 18 and the REED interrupter 20.

The transistor T1 at the output of the device is in series with the winding of the electromagnet 36 · This is with a Power source 3V connected. So there will be a stream through them Winding sent when the transistor T1 is conductive. The reason for this is that valve 35 is closed. The pressure at the end of the nozzle;, · then increases rapidly, and the stream

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DIPL.-1NO- DIETER JANDER DR.-INO. MANFRED BDNINC PATE NTANWALTE

is ejected.

The transistor T1 is controlled by the four inputs E1 to ΈΆ- with the interposition of a series of blocking elements and delay circuits, which are formed by transistors and RC elements.

From Fig. 3 one can see the logic levels for different Points of the circuit diagram of FIG. 2, specifically for points E1 to E4-, A to H and S recognize.

Phases I, II, III, IV, V and VI of the first write cycle are plotted above in FIG. 3. They end with the vertical line 0; this is the end of the first cycle when the write head returns to its home position. Two different cases are shown to the right of line 0: Solid lines: The machine does not receive any new commands to write before the motor is locked. This is the case when the machine is controlled manually from line to line. Dashed lines: The machine receives a new command to write ^{between phases VI and II 1;} the motor is not locked and the write cycle of a second line begins immediately. There is then program control.

When writing the first line, the end of the pulse with I level 1 in B determines the closing of valve 35- This pulse is in turn caused by the V / echsel from 0 to 1 of the I level at input E1, which is caused by starting the I motor. IS takes place at the beginning of phase 1. The duration of the pulse in B h '.'. I depends on the first delay circuit between A and B. It must be such that the pump 51 can assume a state that when the valve 55 is closed, the pressure in the dex ¹ nozzle .5 rises very quickly. For the

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DIPL..INQ. DIETER JANDER DR.-INQ. MANFRED BONINQ PATENT LAWYERS

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In practice this means that this time interval is in the order of magnitude of 10 ms. If phase 1 extends over a period of at least 40 ms, then can you can be sure that the period which is particularly critical in the generation of the beam (this is the period where the risk of dispersion is particularly great), yourself before starting the write head.

If the writing of a second line immediately follows the writing of a first line, then the logic level changes from 1 to 0 at the input E4, which results in the instant of the valve 35 closing. This pulse is controlled by the KEED breaker 20 which the magnet 1S passes by. This happens when the writing head is in the area of the first writing column. This is phase II ¹ .

The speed of the friction head is constant, and, under favorable conditions, the ink jet can form before writing in the first column. At this point: a time of about 20 ms is required.

V / ie in the first write cycle, a pulse appears in B at the beginning of the second cycle. It is triggered by the unlocking pulse in E2, which is controlled in the Hornent of phase IV. A second delay circuit between C and D also generates a blocking pulse in D, which extends at least to phase III '. This pulse ensures that the pulse in B does not open valve 35 prematurely. The valve 35 is not closed until the moment of phase III ¹ .

Preparing to lock the ink jet at the end of a line

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usually not the same problems. On the one hand, the beam can be in a much shorter time be locked by opening the valve 35. On the other hand, the accelerations are at the end of the range of motion of the print head not very large. In the example of FIGS. 2 and 3, the opening of the valve is thereby controlled that the logical level in point E of 1 goes to O at the end of phase IV, which is controlled by input E3.

If it is as a result of the ink used or particularly higher Accelerations at the end of a line is desirable to suppress the beam while increasing speed of the writing head is still uniform, can according to the invention between a signal that appears at E4 and means that the register 45 is empty, and the signal that the clutch 16 controls and is present at E5, a delay is provided be.

To control the valve 35, according to the invention, a Locking of transistor T1 done, which is controlled by an accelerometer, which is on the movement of the print head responds. According to the invention, a closing valve can also be provided at the inlet of the nozzle controlled directly by the accelerations of the print head will.

DJ: DG

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Claims (1)

DIPL.-INQ. DIETER JANDER DR.-INQ. MANFRED BONINC FATE N ADVOCATE claims: 1J Ink jet pen with a writing head which is moved over a recording medium, in which the ink jet is generated under the action of a hydrostatic pressure which forms a convex ink ceniscus at the outlet of a nozzle, and an electric field which causes an attraction in the meniscus direction on the recording medium exerts, characterized in that control members (45) are provided that "the cause of the Elenente (54,55) the formation of the ink jet ⁽¹ I), act in such a manner that a formation of the beam (4) is prevented at least during the acceleration period of the write head (i). 2. Inkjet pen according to claim 1, characterized in that g e that the Gteuerorgane (45) act on the element (34,55) that the hydrostatic Pressure generated, and. the electric load has at least approximately the value it has when the control unit (;; 4, 55) is set in motion. 5. Ink jet pen according to claims 1 or 2, characterized in that the control means (45) the generate hydrostatic pressure when the writing head (1) is still immobile at the start of a write cycle. 4. Ink jet pen according to claims 1 to 5, characterized characterized in that the control organs (45) the emergence of hydrostatic pressure at the beginning of a - 15 209851/0882 DIPL.-1NQ. DIETER JANDER. DR.-INQ. MANFRED BONINC PATENT LAWYERS Prevent the write cycle of a line every time the start of this cycle falls within a time that is less as a certain time counted from the oath of the writing cycle of the previous line, the control elements (45) being put out of action at the moment in at which the writing head has reached an approximately uniform speed, in order to then create the hydrostatic To enable pressure. 5. Ink jet pen according to claim 1, characterized in that a delay circuit
(J3, II, T1) is provided when the drive means is started. (IO-I7) for the write head (1) becomes effective, and that this delay circuit on the control organs (45)
acts to prevent the formation of the jet during the lockout period. 6. Ink jet writer according to claim 1, characterized in that an acceleration indicator (io, 20) is provided which cooperates with the drive ^{elements for the copy 1} and acts on the control elements (A'5) in order to prevent the jet from occurring as long as which: 3> write :: opf (i) accelerates on a certain piece
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