WO1990010540A1 - Process and device for optimising the pressure pulses in ink printers operated by thermal converters - Google Patents

Process and device for optimising the pressure pulses in ink printers operated by thermal converters Download PDF

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Publication number
WO1990010540A1
WO1990010540A1 PCT/EP1990/000141 EP9000141W WO9010540A1 WO 1990010540 A1 WO1990010540 A1 WO 1990010540A1 EP 9000141 W EP9000141 W EP 9000141W WO 9010540 A1 WO9010540 A1 WO 9010540A1
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Prior art keywords
ink
temperature
θ
tfl
pulse
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Application number
PCT/EP1990/000141
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German (de)
French (fr)
Inventor
Ernst Goepel
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Siemens Aktiengesellschaft
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Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, e.g. INK-JET PRINTERS, THERMAL PRINTERS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters 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
    • B41J2/01Ink jet
    • B41J2/015Ink jet characterised by the jet generation process
    • B41J2/04Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04541Specific driving circuit
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, e.g. INK-JET PRINTERS, THERMAL PRINTERS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters 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
    • B41J2/01Ink jet
    • B41J2/015Ink jet characterised by the jet generation process
    • B41J2/04Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04553Control methods or devices therefor, e.g. driver circuits, control circuits detecting ambient temperature
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, e.g. INK-JET PRINTERS, THERMAL PRINTERS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters 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
    • B41J2/01Ink jet
    • B41J2/015Ink jet characterised by the jet generation process
    • B41J2/04Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04563Control methods or devices therefor, e.g. driver circuits, control circuits detecting head temperature; Ink temperature
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, e.g. INK-JET PRINTERS, THERMAL PRINTERS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters 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
    • B41J2/01Ink jet
    • B41J2/015Ink jet characterised by the jet generation process
    • B41J2/04Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/0458Control methods or devices therefor, e.g. driver circuits, control circuits controlling heads based on heating elements forming bubbles
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, e.g. INK-JET PRINTERS, THERMAL PRINTERS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters 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
    • B41J2/01Ink jet
    • B41J2/015Ink jet characterised by the jet generation process
    • B41J2/04Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/0459Height of the driving signal being adjusted
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, e.g. INK-JET PRINTERS, THERMAL PRINTERS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters 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
    • B41J2/01Ink jet
    • B41J2/015Ink jet characterised by the jet generation process
    • B41J2/04Ink jet characterised by the jet generation process generating single droplets or particles on demand
    • B41J2/045Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
    • B41J2/04501Control methods or devices therefor, e.g. driver circuits, control circuits
    • B41J2/04591Width of the driving signal being adjusted
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B41PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41JTYPEWRITERS; SELECTIVE PRINTING MECHANISMS, e.g. INK-JET PRINTERS, THERMAL PRINTERS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005Typewriters 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
    • B41J2/01Ink jet
    • B41J2/17Ink jet characterised by ink handling
    • B41J2/195Ink jet characterised by ink handling for monitoring ink quality

Abstract

Optimising the pressure pulses for electro-thermal converter units in ink printing installations (bubble jet principle) is based on the temperature-dependent viscosity of the fluid ink. As the temperature rises and hence the viscosity falls, the internal friction in the fluid ink flowing through capillary tubes is reduced, as is also therefore the pressure needed to eject the drops as well as the pulse energy. As the electrical pulse energy depends upon the pulse voltage and duration, said pulse voltage and duration are altered according to the measured ink temperature so that, at an ink temperature higher or lower than a threshold value, the converter units are controlled at a reduced or increased pulse energy.

Description

Method and apparatus for optimization of the pressure pulses at operated with thermal transducers ink printing devices

The invention relates to a method and apparatus

for optimization of the pressure pulses in ink printing devices that operate according to the thermal converter principle, in accordance with the features of claims 1 and 7. FIG.

Known ink printheads according to the thermal transducer principle (bubble jet principle) and working example, in

DE-OS 30 12 describes 698, comprise a plurality of individual nozzles from which under the action of an electronic control defined individual droplets to be ejected. The individual nozzles are assigned, are generated by means of actuators in which pressure waves in the ink liquid capillary individual ink channels. The method for

Pressure build-up in the ink liquid based on the generation of Mikrodampfblaschen. In the bottom of each ink channel

is located in a certain distance from the outlet nozzle as an actuator elektrcthermisches a transducer element (heater) in the form which is excited with a voltage pulse of a rectangular thin film electrical heating resistor.

Thus, the ink liquid immediately above the transducer element is in a thin layer on high

Temperatures heated. Over the subsequent evaporation of the heated ink fluid is produced across the transducer element is a vapor bubble (bubble) with high internal pressure, which expansion causes a discharge of a portion of the ink liquid contained in the corresponding ink channel from the nozzle. Since the gas bubbles by briefly energizing the

Thin film heater resistors are created, there is a functional relationship between the electrical pulse energy and the need for ejecting individual droplets pressure pulse. The pulse energy is determined by the to the

Converting element applied pulse voltage by the electric resistance of the transducer element (dot-resistance) and by the pulse duration of the applied voltage. In order to ensure a safe Tropfchenausstoß from the nozzles, the pulse energy must on the one hand a predetermined value not less than the other hand, the conditional due to the thermal converter principle heating of the ink print head with unnecessary high energy pulse should not be increased.

The invention therefore has for its object to provide measures for optimization of the pressure pulses to the electrothermal transducing elements in ink printing devices of the type mentioned, which make it possible to provide an ink temperature matched pulse energy for the transducer elements, without causing the printing quality is impaired.

This object is achieved according to the features of claims 1 and 7. FIG. Advantageous embodiments are characterized in the subclaims.

According to the invention, the temperature dependence of the viscosity of flowing capillaries in the ink liquid is utilized. Additionally the temperature of the ink liquid is measured and compared with a predetermined limit value. e di amplitude of the provided for driving the thermal transducer elements pulse voltage or the pulse duration, the measured temperature is above this threshold, it is reduced so that the transducer elements supplied pulse energy is reduced. The optimization of the pressure pulse can also be done both pulse amplitude and pulse duration through joint change. Through such optimization of the pressure pulses can be achieved easily changing the pressure energy without compromising print quality. If the pressure energy at a reduced, compared with the limit value elevated ink temperature, so a reduction of the ink jet print head heating is also achieved. This gives the advantage of a smaller ink print head cooling surface or an increase in pressure data throughput, so a greater

Amount of data per time unit can be processed without causing the ink print head is heated excessively. Through such a reduced pressure energy, the ratio can be considerably improved operating phase cooling phase of the inkjet print head.

Particularly simple manner, the temperature of the ink liquid can be detected, when a temperature sensor is arranged on the ink printing head in the region of the ink reservoir. Because of the proximity and thus good thermal coupling, the temperature of the ink liquid by the temperature of the ink jet print head in the area of ​​the ink reservoir can be replaced with sufficient accuracy.

Is used to changeover from a high pressure pulse of energy to a lower pressure pulse energy, a comparator having

Bridge resistor network used, whose output drives an already existing for the control of the thermal converter adjustable voltage regulator, so the effort for the optimization reduced to a few standard components, whereby the whole a low cost device.

The invention will be explained in the following using a preferred embodiment, wi which reference is made to the Darstelllungen approx. show there

1 shows the temporal profiles of the driving voltage and the pressure pulse and in a schematic way the Dampfblasenund droplet generation,

2 shows the temperature dependence of the kinematic viscosity suitable for printing with thermal transducers ink liquid,

3 shows the dependence of the pulse energy, pulse voltage and pulse width of the ink temperature,

4 is a block diagram of an apparatus for the optimization of the pressure pulses and

5 shows another way to optimize pressure pulses in a detailed representation. The left half of Figure 1 shows a value suitable for the control of electrothermal transducer elements voltage square wave pulse, which is characterized by its amplitude U and the pulse duration T. Moreover, the temporal course of the pressure pulse P, located in an ink channel TK, which ultimately leads to the ejection of ink droplets from the nozzles of a Tinteπdruckkopfes. On the time axis t individually selected time points t 1 to t 7 are marked, in which are reflected by means of the right half of FIG vapor bubble generating schematically illustrated 1 with subsequent droplet ejection operation. There are in each case to the individual time points t 1 to t 7 associated side views of the ink channel TK shown. The thermal transducer element is represented by its electrical resistance R D.

At time t 1, the pulse voltage is applied to the transducer element, it begins to heat up, and the ink liquid is heated TFL. From the time t 2, the pressure within the ink channel TK begins to build and develop an ink vapor bubble TBL. This continues to grow until a time t 4, although the pulse voltage already (time t 3) was previously switched off. The pressure pulse P I had its maximum value at this time. The ink vapor bubble collapses TBL (times t 5, t 6) and an ink droplet is ejected TTR. The ink vapor bubble draws TBL upon collapse the meniscus at the nozzle outlet back, the refilling of the nozzle with ink from the ink reservoir is accomplished by the capillary force of the meniscus. At time t 7 is the initial state (time t 1) is restored and a new droplet ejection can be initiated.

Since the one hand, in ink ejection, among other things, the internal friction force of the air flowing in the capillaries ink liquid must be overcome by the pressure pulse and on the other hand, there is a proportionality between the frictional force and the kinematic viscosity of the ink liquid is obvious that reduces with decreasing viscosity, the friction force. This creates the necessary for droplet ejection pressure pulse and the pulse energy is reduced. At the

Printing operation now heats up due to the thermal converter principle of Tintendruckkkopf, wherein a printing throughput (= amount of pressure / time), the ambient temperature and the cooling surface of the ink print head-dependent temperature of the ink print head is established. As a spatially and thermally with these associated ink reservoir (not shown) located on the ink jet head immediately adjacent to the capillary nozzles, the temperature of the ink liquid in the reservoir increases with increasing ink print head temperature to the same extent, that is, with a sufficiently high accuracy the temperature of the ink jet print head may be the same the temperature of the ink liquid to be set.

2 shows the temperature dependence of the kinematic viscosity V T is a suitable for the Tintenαruck with thermal transducers ink liquid TFL shown. The kinematic viscosity V T is the quotient of the

dynamic viscosity and density of the ink liquid defined. From the drawn curve it is seen that, for example, in an ink temperature T of θ

20 ° C is the kinematic viscosity V T 5.5 mm 2 / s, while it has, at an ink temperature of 45 ° C has a value of 2.5 mm 2 / s. This characteristic that the kinematic viscosity V T of the ink liquid TFL falls with rising temperature is advantageously utilized according to the invention for optimization of the pressure pulses. For a warmer ink print head with low viscous ink liquid characterized TFL therefore for printing a lower pulse energy is sufficient as a colder ink print head with highly viscous ink liquid TFL without that changes the ink ejection.

According to the relationship for the pulse energy E I =

(U 2 / R D). T I can this optimization by one of the ink temperature T θ of the ink liquid adapted TFL happen U change in the amplitude of the pulse voltage and / or the pulse duration T I. The functional relationship between these sizes, and the ink temperature is shown in FIG 3. Here, the abscissa represents the temperature θ T of Tintenflussigkeit TFL applied in ° C and the ordinate represents the pulse duration T I in microseconds, the square of the amplitude are in different scales U 2 of the pulse voltage plotted in V 2, and a relative pulse energy e I / e I in percent. For the following discussion, the use of an ink liquid is provided, the temperature-dependent viscosity V T having a profile in accordance with the embodiment shown in Figure 2 curve. Is operated, for example, an ink print head in thermal transducer technology, the electrical resistance of the transducer elements R Di = 80Ω is, at a temperature of the ink print head TDK ≈ θ T θ = 35 ° C, a Impulsspanπung with an amplitude U according to Figure 3 for secure droplet ejection = 20 V and a pulse duration T I = 6.5 microseconds required. The relative pulse energy E I '/ E I is then set to 100%. the temperature of the ink jet print head and thus the temperature of the ink liquid during printing operation and / or increased by the ambient temperature, for example, 50 ° C, the pulse energy can be lowered by 15% according to Figure 3, without thereby varying the droplet ejection. But this means that at constant pulse voltage amplitude U = 20 V, the pulse duration T I of 6.5 microseconds to 5.5 microseconds or at a constant pulse duration T I = 6.5 microseconds, the amplitude U of the pulse voltage of 20 V on 18.4 V are reduced. Likewise, a common reduction of the pulse voltage amplitude U and the pulse duration T I is possible such that the decrease in pulse energy does not exceed a value of 15%. In Figure 4 is a possible device for the above

Optimizing the pressure pulses P I described schematically illustrated in the form of a block diagram. A after

Thermal converter principle working ink printing device, as described for example in DE-OS 30 12 698 in detail, has an ink print head TDK having the thermal converter here only schematically shown with their heating resistors R d i. In the ink jet print head TDK in the immediate vicinity of an ink reservoir, not shown here, a temperature sensor is arranged TF. With this TF temperature sensor, which may be realized for example as a thermistor, PTC, silicon device, or as a thin film resistor, the temperature θ TDK the ink print head TDK detected. Because of the geographical proximity and therefore the intimate thermal coupling of the temperature sensor TF to the present in the ink reservoir ink liquid TFL the detected temperature can θ TDK the ink print head TDK be used as a measure of the temperature of the ink liquid TFL (θ T ≈ θ TDK). The signal of the temperature sensor TF is supplied via an analog / digital converter AD in digitized form a central controller ZS of the ink printing device. In the central controller ZS can be a known per se, in any case necessary for printing control device which electronically processes the data to be printed DA and forwards an ink print head control TKS, which in turn activates the thermal converter on individual, not shown electronic switches. In particular, the central controller ZS can also be realized by a known microprocessor control. According to the characteristic curve of Figure 3, which is based on the characteristic shown in Figure 2 and in a memory of the central control SP ZS is stored, the pressure pulse energy is dependent on the measured temperature θ TDK set. This is done by means of the parameters pulse duration T I and / or the amplitude U of the pulse voltage, with which the thermal converter can be controlled via the ink printing head control TKS. The drive voltage can be generated in a known manner via a voltage regulator.

5 shows a further embodiment of a device for switching from a high pressure pulse energy E I to a lower energy E I 'after reaching a predetermined limit temperature for the liquid ink. The solution according to the manner described with reference to the Figure 4 apparatus is simplified here by replacing the analog / digital converter with bridge comparator resistor network and a comparator output, controlled by the pulse voltage source. When only partially shown here inkjet print head driver TKS only The ones parts are shown which are necessary for an understanding of the inventive device. These are provided in detail in accordance with the number of thermal transducer R Di druckergesteuεrte electronic switch ES i to ES n to release the pulse voltage during the pulse duration, a pulse voltage source UBB and a comparator K. The ink jet print head TDK includes a plurality of thermal transducers in a known manner are integrated on a single substrate and having the heating resistors indicated in the figure 5 with R to R Dl Dn. The individual heating resistors R Di assigned via separate lines, for example in the form of conductor tracks, the individually controllable electronic switch ES 1 to ES n, which are connected to the actual print character generating means and have the task of the transducer elements with their heating resistors R Dl to R to put pressure Dn character-dependent on the drive voltage. For this, a port of the heating resistors R Di to the collector of the corresponding electronic switch ES i is guided in each case. The emitters of the electronic switch ES i are connected to a reference potential 0 V, for example, to the ground line. The other terminals of resistances R Di are capable of all Heizwiderstäπden R ~. together common line, via which they are connected to a pulsed voltage source UBB. In the ink jet print head TDK the TF temperature sensor is arranged in the immediate vicinity of an ink reservoir, not shown here, in addition. In this embodiment, a thermistor is used as temperature sensor TF, its resistance at a particular temperature of the ink liquid θ T is referred to as resistance R TF. While a lead wire of the temperature sensor TF is connected to the reference potential, the other terminal is located at the inverting input of a comparator K. This comparator K is operated with a related respectively to the mass of the positive and negative supply voltage UCC. Between the positive terminal of the supply voltage UCC and the ground potential, a series circuit of two resistors R 4 and R 5 is connected. An unspecified connection point between these two resistors is led to the noninverting input of the comparator K. In addition, there is still a resistance R6 between the positive terminal of the supply voltage UCC and the inverting input of the comparator K. The output A of the comparator K is connected to the base of a switching transistor ST, whose collector adjustable via a resistor R 2 to a set input ADJ a voltage regulator SR is performed. To the input terminal V IN of this voltage regulator SR the pulse voltage source UBB is on and the Ausgangsklemmme

V OUT is connected to all transducer elements common connection line. In addition, at the output V OUT of the voltage regulator SR, a series circuit of two resistors R is connected to ground 3 and R. 1 The connection point of the two resistors R 3, R 1 is performed on the setting input ADJ. As a voltage regulator SR the block LM 317T example, Texas Instruments

be used. Since the apparatus described is intended to reduce the pressure pulse energy after reaching a predetermined limit temperature for the liquid ink, this temperature limit must be set first (for example, 50 ° C). This is done using of a reference voltage divider consisting of the resistors R 4 and R. 5 The temperature θ T of the ink liquid TFL is detected by the temperature sensor and TF is given by the measuring voltage divider, consisting of resistors R 6 and R TF. If the temperature of the ink liquid TFL less than or equal to the stands by the reflection R 4 and R 5 set limit temperature, the output A of the comparator K is at a logic

"Low" state corresponding level, the switching transistor

ST is locked with it. The amplitude U of the pulse voltage at the output V OUT of the voltage regulator SR is determined by the voltage divider resistors R 3 and R 1 is determined (for example, U = 20 V). the temperature of the ink liquid TFL increases, for example, during the printing operation to a value that is above the threshold temperature, the comparator switches to K, its output A is located on a DETR logic "high" level corresponding. Thus, the switching transistor ST is triggered and set to the conductive state. Since the emitter of the switching transistor ST is connected to the reference potential, characterized the resistor is connected in parallel with the resistor R 1 in addition R.sub.2. To the so modified voltage divider R 1, R 2, R 3 is now a greater voltage drops, so that the amplitude of the pulse voltage U 'is reduced (U' to a value U example, 18.4 V). Characterized decreases, as mentioned at the outset and explained with reference to Figure 3, with the pulse voltage, the pressure pulse energy.

In the illustrated embodiment, the pulse duration T I, with which the thermal converter resistors R to R Dl Dn via the electronic switch ES ES 1 to n is controlled printers are activated, constant (for example, 6.5 microseconds) is held. However, the output A of the comparator K can be used in connection with the not shown central control ZS of the ink jet print device and for switching the pulse duration of T I to T I '

(For example, 5, 5 microseconds) are used, wherein the amplitude U of the pulse voltage would be kept constant, or it could be controlled in common to the output A of the comparator K, both the pulse voltage and the pulse duration. The optimization of the pressure pulses was in this

Example based on a reduction in the energy pulse described with increasing ink temperature. However, it is also within the scope of the invention to increase the pulse energy from one of the ambient temperature corresponding value, ie, the amplitude and / or pulse duration to increase. This could be useful, for example, when the ink jet print device is operated at extremely low Umgebungsgtemperaturen and is insufficient provided for keeping constant the ink Tintenvorheizung to enable an undisturbed pressure operation.

Claims

claims
1. A method for optimizing the pressure pulses (P I) in
Ink printing devices, the ink jet print heads (TDK)
a plurality of individual, with a pulse voltage (UBB) via electronic switch (ES i) selectively drivable electrothermal transducing elements (RD i) that which is associated with (TK) are each an ink channel, wherein in the printing operation, these transducer elements (RD i) an ink liquid ( TFL) locally heat and thereby ink droplets (TTR) from nozzles of the ink channels (TK) to be ejected,
with the following characteristics:
a) the viscosity (γ T) of the ink liquid (TFL) is (via the temperature θ T) of the ink liquid (TFL)
detected,
b) the temperature thus determined (θ T) is compared with a predetermined limit value,
c) depending on the result of this comparison, the pulse energy (E I) and the pressure pulse is adjusted (P I) of the measured temperature (θ T) of the ink liquid (TFL).
2. The method of claim 1, characterized
in that the adjustment of the pulse energy (E I) by changing the amplitude (U) of the pulsed voltage (UBB) and / or the pulse duration (T I) is effected such that at a relative to the threshold elevated temperature, the ink liquid (TFL) which the transducer elements (RD i) supplied to the pulse energy (e I) is reduced.
3. The method according to claim 1 or 2, characterized
in that the temperature (θ T) of the ink liquid (TFL) indirectly via the temperature (θ TDK) of the ink print head (TDK) from one arranged in the region of an ink reservoir temperature sensor (TF) is detected.
4. The method according to claim 2, characterized
in that the variation of the amplitude (U) of the pulsed voltage (UBB) by changing the external circuit resistors (R 1, R 2, R 3) of an adjustable voltage regulator (SR) is carried out.
5. The method according to claim 4, characterized
in that the change in the circuit resistors (R 1, R 2, R 3) from the output (A) of the threshold temperature and the measured temperature (θ T) of the
The ink print head (TDK) comparative comparator (K) is controlled.
6. The method according to claim 1, characterized in that the temperature signal (θ T) over a
Analog / digital converter (AD) to the central controller (ZS) is supplied to an ink printing device that includes a memory (SP), in which the values for the required pulse energy depending on the measured ink temperature (θ T) are stored (E I), with which the transducer elements (R Di) via an ink printing head control (TKS) are driven.
7. An apparatus for optimizing the pressure pulses (P I) in
Have ink printing devices, the ink jet print heads (TDK) a plurality of individual with a pulse voltage (UBB) via electronic switch (ES i) selectively drivable electrothermal transducing elements (R Di), each associated with an ink channel (TC), wherein (in press operation, this transducer elements R Di) an ink liquid (TFL) locally heat and thereby ink droplets (TTR) from nozzles of the ink channels (TK) are ejected, with the following features:
a) on the ink printing head (TDK) is in the range of
Tinteπreservoirs a temperature sensor (TF) is arranged, the signals of an ink printer head driver (TKS) are fed,
b) containing the ink printer head driver (TKS) a
Comparing circuit (K, R 4, R 5, R 6) which is connected to the
Tewmperaturfühler (TF) measured temperature (θ T) of
compares ink liquid (TFL) with a predetermined limit,
c) the comparator circuit (K, R 4, R 5, R 6) with a regulating device (SR) is connected, which the transducer elements (R Di) supplied pulse energy (E I) of the measured temperature (θ T) of the ink liquid (TFL ) adapts.
8. Apparatus according to claim 7, characterized in that on the control device (SR) which
Pulse voltage (UBB) is applied and at an opposite limit the elevated temperature (θ T) of the ink liquid (TFL), the amplitude (U) of the pulsed voltage (UBB) is reduced.
9. The device according to claim 7 or 8, characterized
in that the comparator circuit (K, R 4 to R 6) comprises a comparator (K) with resistors contains (R 4, R 5, R 6) whose output (A) via an electronic switch (ST) to the control input (ADJ ) of the
Control circuit (SR) is guided.
10. The apparatus of claim 7 or 8, characterized in that as a regulating circuit (SR) is used, an adjustable voltage regulator, the external resistor circuit (R 1 to R 3) depending on the measured temperature (θ T) of the ink liquid (TFL) is changed.
PCT/EP1990/000141 1989-03-14 1990-01-25 Process and device for optimising the pressure pulses in ink printers operated by thermal converters WO1990010540A1 (en)

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Application Number Priority Date Filing Date Title
EP89104479 1989-03-14
EP89104479.4 1989-03-14

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Cited By (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0496525A1 (en) * 1991-01-18 1992-07-29 Canon Kabushiki Kaisha Inkjet recording method and apparatus using thermal energy
EP0558221A2 (en) * 1992-02-24 1993-09-01 Xerox Corporation Electronic spot size control in a thermal ink jet printer
EP0650838A2 (en) * 1993-10-29 1995-05-03 Hewlett-Packard Company Thermal turn on energy test for an ink-jet printer
WO1996032275A1 (en) * 1995-04-12 1996-10-17 Eastman Kodak Company Heater power compensation for temperature in thermal printing systems
US5751302A (en) * 1996-03-29 1998-05-12 Xerox Corporation Transducer power dissipation control in a thermal ink jet printhead
US5781205A (en) * 1995-04-12 1998-07-14 Eastman Kodak Company Heater power compensation for temperature in thermal printing systems
US5861895A (en) * 1991-01-09 1999-01-19 Canon Kabushiki Kaisha Ink jet recording method and apparatus controlling driving signals in accordance with head temperature
US6328407B1 (en) 1999-01-19 2001-12-11 Xerox Corporation Method and apparatus of prewarming a printhead using prepulses

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Cited By (16)

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Publication number Priority date Publication date Assignee Title
US5861895A (en) * 1991-01-09 1999-01-19 Canon Kabushiki Kaisha Ink jet recording method and apparatus controlling driving signals in accordance with head temperature
EP0496525A1 (en) * 1991-01-18 1992-07-29 Canon Kabushiki Kaisha Inkjet recording method and apparatus using thermal energy
US6310636B1 (en) 1991-01-18 2001-10-30 Canon Kabushiki Kaisha Ink jet recording method and apparatus for driving recording head based on head temperature
US6116710A (en) * 1991-01-18 2000-09-12 Canon Kabushiki Kaisha Ink jet recording method and apparatus using thermal energy
US5894314A (en) * 1991-01-18 1999-04-13 Canon Kabushiki Kaisha Ink jet recording apparatus using thermal energy
EP0694406A3 (en) * 1991-01-18 1996-04-03 Canon Kk Ink jet recording method and apparatus using thermal energy
EP0686506A3 (en) * 1991-01-18 1996-04-03 Canon Kk Ink jet recording method and apparatus using thermal energy
US6457794B1 (en) 1991-01-18 2002-10-01 Canon Kabushiki Kaisha Ink jet recording method and apparatus for controlling recording signal parameters
EP0558221A3 (en) * 1992-02-24 1993-12-22 Xerox Corp Electronic spot size control in a thermal ink jet printer
EP0558221A2 (en) * 1992-02-24 1993-09-01 Xerox Corporation Electronic spot size control in a thermal ink jet printer
EP0650838A3 (en) * 1993-10-29 1996-01-10 Hewlett Packard Co Thermal turn on energy test for an ink-jet printer.
EP0650838A2 (en) * 1993-10-29 1995-05-03 Hewlett-Packard Company Thermal turn on energy test for an ink-jet printer
WO1996032275A1 (en) * 1995-04-12 1996-10-17 Eastman Kodak Company Heater power compensation for temperature in thermal printing systems
US5781205A (en) * 1995-04-12 1998-07-14 Eastman Kodak Company Heater power compensation for temperature in thermal printing systems
US5751302A (en) * 1996-03-29 1998-05-12 Xerox Corporation Transducer power dissipation control in a thermal ink jet printhead
US6328407B1 (en) 1999-01-19 2001-12-11 Xerox Corporation Method and apparatus of prewarming a printhead using prepulses

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