GB2219145A - Compensating for residual strain of a piezoelectric element - Google Patents
Compensating for residual strain of a piezoelectric element Download PDFInfo
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- GB2219145A GB2219145A GB8910391A GB8910391A GB2219145A GB 2219145 A GB2219145 A GB 2219145A GB 8910391 A GB8910391 A GB 8910391A GB 8910391 A GB8910391 A GB 8910391A GB 2219145 A GB2219145 A GB 2219145A
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- 238000000034 method Methods 0.000 claims description 16
- 230000002401 inhibitory effect Effects 0.000 claims description 10
- 230000006870 function Effects 0.000 claims description 5
- 238000006073 displacement reaction Methods 0.000 description 43
- 230000008859 change Effects 0.000 description 12
- 230000009471 action Effects 0.000 description 9
- 239000011159 matrix material Substances 0.000 description 7
- 230000007423 decrease Effects 0.000 description 6
- 230000006866 deterioration Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 238000001514 detection method Methods 0.000 description 1
- 238000003384 imaging method Methods 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
Classifications
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- 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
- B41J2/015—Ink jet characterised by the jet generation process
- B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
- B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
- B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
- B41J2/04581—Control methods or devices therefor, e.g. driver circuits, control circuits controlling heads based on piezoelectric elements
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- 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
- B41J2/015—Ink jet characterised by the jet generation process
- B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
- B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
- B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
- B41J2/04588—Control methods or devices therefor, e.g. driver circuits, control circuits using a specific waveform
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- 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
- B41J2/015—Ink jet characterised by the jet generation process
- B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
- B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
- B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
- B41J2/04596—Non-ejecting pulses
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- 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
- B41J2/015—Ink jet characterised by the jet generation process
- B41J2/04—Ink jet characterised by the jet generation process generating single droplets or particles on demand
- B41J2/045—Ink jet characterised by the jet generation process generating single droplets or particles on demand by pressure, e.g. electromechanical transducers
- B41J2/04501—Control methods or devices therefor, e.g. driver circuits, control circuits
- B41J2/04598—Pre-pulse
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- H—ELECTRICITY
- H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
- H10N30/00—Piezoelectric or electrostrictive devices
- H10N30/80—Constructional details
- H10N30/802—Circuitry or processes for operating piezoelectric or electrostrictive devices not otherwise provided for, e.g. drive circuits
Landscapes
- General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)
Abstract
A system for controlling a piezoelectric element whose strain varies with a voltage applied thereto and which has a residual strain left after removal of the voltage, such that a difference in the amount of the residual strain before and after an energization of the piezoelectric element varies depending upon a hysteresis of the piezoelectric element before the energization. The system is adapted such that at least one preliminary energization of the piezoelectric element is effected, prior to a primary energization cycle of the piezoelectric element, at least where the difference is equal to or larger than a predetermined value. The primary energization cycle includes at least one primary energization of the piezoelectric element for attaining a desired function. The disclosed system is capable of eliminating an error of the actual amount of residual strain of the piezoelectric element from the nominal value, which may arise from different operating conditions of the element, such as energization time, time duration between successive energizations, and temperature variations of the element. <IMAGE>
Description
APPARATUS HAVING PIEZOELECTRIC ACTUATOR, AND
METHOD OF CONTROLLING THE PIEZOELECTRIC ELEMENT
The present invention relates to an apparatus having a piezoelectric actuator and a method of controlling a piezoelectric element constituting an essential part of the piezoelectric actuator, and more particularly to improvements in such apparatus and method, for eliminating or miminizing operational drawbacks due to variation in the amount of residual strain of the piezoelectric element.
A piezoelectric element is an element whose amount of strain changes with a change in the level of a voltage applied thereto, such that the amount of strain increases with an increase in the voltage level. This change in the amount of strain of the piezoelectric element is utilized to drive a desired apparatus or instrument. On the other hand, the piezoelectric element has a residual strain which exists even with voltage removed therefrom. When a voltage is applied to the piezoelectric element having a certain amount of residual strain,the total amount of strain of the element increases from the present amount of the residual strain. With the voltage removed, the total amount of strain of the element is reduced to the amount of the residual strain.Namely, the removal of the voltage causes the working end of the piezoelectric element to return to the original position defined by the amount of the residual strain. This displacement of the piezoelectric element based on a varying amount of strain is utilized as a drive source of the piezoelectric actuator.
As an example of the apparatus or instruments utilizing such a piezoelectric actuator, there are known a dot-matrix impact print head, an ink jet print head, a high-precision positioning device, a swing CCD
(charge-coupled device) imaging apparatus, and a VTR head controller. In a dot-matrix impact print head, for instance, each of a plurality of print wires W which are axially movable to force a print ribbon against a recording paper is connected to a corresponding piezoelectric actuator PA.As shown in Fig. 11, the actuator PA includes a piezoelectric element P consisting of a plurality of superposed layers, and a displacement amplifying mechanism
M which is adapted to amplify the amount of displacement of the working end face of the piezoelectric element P (hereinafter simply referred to as "displacement of the piezoelectric element"). The piezoelectric elements P of the piezoelectric actuators PA are slectively energized with a suitably controlled voltage, depending upon the desired characters to be printed, whereby the print wires W connected to the energized piezoelectric elements P are axially advanced due to the change in the amount of strain of the elements P, whereby the characters are printed by the wires W via the print ribbon.
The residual strain of the piezoelectric element generally decreases with an increase in its temperature.
That is, the residual strain of the piezoelectric element has a negative temperature coefficient or dependence.
Further, once the residual strain of the piezoelectric element is reduced, the residual strain will not increase even with a subsequent lowering of the temperature, unless a voltage is again applied to and removed from the element.
It is also noted that a certain period of time is required for the residual strain of the piezoelectric element to be reduced with a rise of its temperature. Accordingly, a change in the temperature of the piezoelectric element during a time period between successive energizations of the element may sometime cause absolutely no change in the amount of the residual strain, or cause an imcomplete change-in the amount of the residual strain with respect to the temperature change. In such cases, there arises a change in the amount of the residual strain, in addition to a change in the amount of the normal strain which appears by the application of a voltage to the piezoelectric element and disappears by the removal of the voltage.
Consequently, the total amount of strain of the piezoelectric element consists of the amount of the normal strain corresponding to the level of the voltage applied, and a change in the amount of the residual strain which is added to or subtracted from the normal strain. In other words, the total amount of strain of the piezoelectric element includes an error from the nominal value, whose amount varies depending upon the hysteresis of the piezoelectric element during a time period between the last and present energizations of the element. However, the amount of the residual strain after removal of the voltage applied for the present energization becomes equal to the nominal amount which corresponds to the temperature at the moment of the voltage removal.Thus, there arises a difference between the pre-energization and post-energization amounts of the residual strain before and after a given energization of the piezoelectric element. If the amount of this difference is relatively large, the total amount of the strain and consequently the amount of displacement of the piezoelectric element vary to a considerable extent, between the moments of the last and present energizations, and between the moments of the present and next energizations. This causes an undesirable variation or fluctuation in the amount of operation or displacement of the piezoelectric actuator.
The above problem will be described referring to an example wherein the piezoelectric actuator is used for a printer having a dot-matrix impact print head. In the present example, each piezoelectric element of the piezoelectric actuator exhibits a relationship between the amount of displacement and the temperature, as indicated in the graph of Fig. 12. Described more specifically, the amount of displacement corresponding to the residual strain is about 13 microns at OOC, and the displacement is reduced to zero at about 130 0C. The graph of Fig. 13 illustrates a variation in the amount of displacement of the piezoelectric element in different operating conditions.
The following description is based on the assumption that a residual strain exists in the piezoelectric element, at the time the element is initially energized.
With a voltage initially applied to the piezoelectric element, the strain of the element increases by an amount A from Point b to Point b'. With the voltage removed thereafter, the strain is reduced back to Point b".
During an operation of the print head, such an energization of the piezoelectric element with voltage application and removal is usually repeated. As a result, the temperature of the piezoelectric element rises, due to heat generated by the piezoelectric element per se and/or heat generated by the components surrounding the piezoelectric element.
The amount of residual strain of the piezoelectric element decreases with an increase in its temperature. Accordingly, the amount of displacement of the element in its non-energized state, i.e., the amount of displacement corresponding to the residual strain of the element gradually decreases as indicated in solid line d-d' in Fig.
13, whereby the position (indicated at c', d') of the working end face of the piezoelectric element at the time of energization thereof is changed.
Suppose the above operation cycle of the piezoelectric element indicated at I in Fig. 13 is followed by a non-operating time interval indicated at II. In this time interval, the temperature of the piezoelectric element is lowered. Since the piezoelectric element is not energized during the non-operating time interval II, the amount of the residual strain of the element is maintained at the value at the end of the operation cycle I, because the residual strain will not increase even with a decrease in the temperature.When the next operation cycle III of the piezoelectric element is effected, therefore, the displacement amount B of the element which is caused by an initial energization in that cycle III is a sum of the displacement amount A in the last operation cycle I, and a displacement amount L which corresponds to an amount of the residual strain corresponding to an amount of decrease in the temperature during the non-operating time interval II.
The displacement amount L is considered an amount of error of the residual strain, that is, a difference between the actual amount of residual strain of the piezoelectric element immediately before the initial energization in the operation cycle III, and the nominal amount of residual strain of the element which corresponds to the temperature of the element immediately before the initial energization.
Therefore, the total amount B of displacement of the piezoelectric element from Point e to Point e' which is caused by the initial energization is larger than the displacement amount A in the operation cycle I. Since the error of the residual strain has been eliminated or considerably reduced by the displacement B caused by the initial energization, the second and subsequent displacement amounts in the operation cycle III are restored to the nominal amount A or reduced to a value close to the nominal amount. Thus, the displacement amount
B is also larger than the displacement amounts (indicated by g, g') caused by the second and subsequent energizations in the operation cycle III.Consequently, the printing pressure established by the initial energization of the piezoelectric element in the operation cycle III is higher than that established by the last energization in the operation cycle I and the second energization in the operation cycle III. As a result, the printing quality is deteriorated by locally increased density of printed dot due to the comparatively higher printing pressure indicated above.
There will next be described a drawback which is enountered where the temperature of the piezoelectric element rises during the non-operating time interval. This situation is possible where the ambient or room temperature of the printer rises from the level at the end of the last operation cycle, for example. In this case, there arises no problem, if the non-operating time interval up to the moment of the next energization of the piezoelectric element is sufficiently long for the amount of rise of the temperature. If this interval is not sufficiently long, the total displacement of the piezoelectric element caused by the first energization after the non-operating interval includes an amount by which the residual strain should have been reduced due to the temperature rise prior to the commencement of the present operation cycle.In other words, the total displacement amount caused by the first energization of the present operation cycle following the non-operating time interval includes an error which is a difference between the nominal and actual amounts of residual strain of the piezoelectric element immediately before the first energization. Namely, the first energization does not provide a sufficient amount of total displacement of the piezoelectric element. Thus, where the non-operating time interval is insufficient, the printing pressure established by the initial energization following the non-operating time interval is lower than that established by the preceding and following energizations, whereby the printing quality is deteriorated, as in the case of the temperature lowering during the non-operating time.
The amount of residual strain of the piezoelectric element decreases with a non-operating or non-energization time, even without a change in the temperature of the element. Hence, if the non-energization time is relatively long, the amount of residual strain of the piezoelectric element immediately before the initial energization following the non-energizating time may differ from the nominal amount, and the total displacement amount produced by the initial energization may accordingly differ from the nominal amount, whereby the amount of operation of the piezoelectric actuator may fluctuate, as in the preceding cases.
This drawback will be described in connection with the printer described above, by way of example. In this example, the piezoelectric element exhibits a relationship between the amount of displacement due to the residual amount, and the non-energization time, as indicated in the graph of Fig. 14. More specifically, the residual strain is reduced from the initial amount of 10 micron, and eventually zeroed after several months of non-energization time for which the piezoelectric element is held at 2000.
The following description is based on an assumption that the piezoelectric element is energized once for each operation cycle.
In the first energization in the first operation cycle, a voltage applied to the piezoelectric element results in its displacement by an amount indicated at A in
Fig. 15, from Point i to Point i'. With the voltage removed, the position of the working end of the element is returned to Point j. The second energization takes place a considerable non-energization time after the first energization. As a result, the piezoelectric element has a displacement amount D from Point k to Point k', which is a sum of the displacement amount A, and a displacement amount
M which corresponds to a difference between the nominal and actual amounts of the residual strain. With the voltage removed, the position of the working end of the piezoelectric element is returned to Point 1.Where the temperature of the element immediately after the first energization is the same as that immediately before the second energization, the displacement amount M corresponds to an amount by which the residual strain is reduced due to the passage of the non-energization time. Thus, the total displacement amount D produced by the second energization is larger than the displacement amount A produced by the first energization, whereby the printing pressure is accordingly increased, causing deterioration of the printing quality of the printer.
SUMMARY OF THE INVENTION
It is therefore a first object of the present invention to provide a method of controlling an apparatus driven by a piezoelectric actuator including a piezoelectric element whose amount of residual strain before and after an energization thereof varies depending upon a hysteresis of the piezoelectric element before the energization, which method is capable of reducing the conventionally experienced problem of instability of the operating amount of the piezoelectric element for the reasons described above.
A second object of the invention is to provide an apparatus driven by a piezoelectric actuator including a piezoelectric element as described above, which apparatus does suffers less from the above-indicated problem experienced in the prior art.
The first object may be achieved according to one aspect of the present invention, which provides a method of controlling an apparatus which is driven by a piezoelectric actuator including a piezoelectric element whose strain varies with a voltage applied thereto and which has a residual strain left after removal of the voltage, such that a difference between a pre-energization amount and a post-energization amount of the residual strain before and after an energization of the piezoelectric element with the voltage varies depending upon a hysteresis of the piezoelectric element before said energization, comprising the step of effecting at least one preliminary energization of the piezoelectric element, prior to ' a primary energization cycle of the piezoelectric element, at least where the difference of the pre- and post-energization amounts of the residual strain of the piezoelectric element is equal to or larger than a predetermined value. The primary energization cycle includes at least one primary energization of the piezoelectric element for attaining a desired function.
The preliminary energization of the piezoelectric element may be effected before each primary energization cycle of the piezoelectric element, or may be effected only where the difference of the residual strain before and after the primary energization cycle exceeds the predetermined value. However, each preliminary energization of the piezoelectric element is preferably effected before the primary energization cycle, and before an amount of error of the actual residual strain from the nominal value immediately before the primary energization cycle exceeds a predetermined amount. The level of a preliminary voltage applied to the piezoelectric element for the preliminary energization thereof may be large enough to completely eliminate the above-indicated error of the residual strain, or may be determined so as to reduce the error by a suitable amount.
In the method of the present invention for controlling the piezoelectrically driven apparatus in the manner as described above, the piezoelectric element is preliminarily energized at least once to eliminate or reduce the error of the residual strain of the element, prior to the primary energization cycle, at least where the amount of error of the residual strain is equal to or larger than the predetermined value. Accordingly, the amount of displacement of the piezoelectric element as a result of the primary energization cycle may be made equal or substantially equal to a desired nominal value, so that the operating amount of the piezoelectric actuator may be maintained constant, for attaining the desired operational function.
In a printer equipped with a piezoelectrically operated print head of a dot-matrix impact type or ink jet type, for example, it is important to maintain a constant printing pressure in order to assure high stability of printing quality such as density of printed characters. The printing pressure is influenced by the position of the piezoelectric element upon application of a voltage, and an amount of displacement caused by the voltage application.
According to the present invention, the amount of displacement of the piezoelectric element upon each primary energization thereof is made substantially constant, owing to the preliminary energization, whereby a variation in the printing pressure is minimized, and the printing quality is accordingly enhanced.
A temperature compensating member in the form of a metal block which has a positive temperature dependence and expands with an increase in temperature may be provided in series with the working or driving surface of the piezoelectric element, so that an amount of reduction in the residual strain of the piezoelectric element due to the temperature rise is compensated for by the expansion of the metal block. If the method of the present invention is practised for the piezoelectric print head equipped with such a temperature compensating member, the position of the piezoelectric element upon each primary energization cycle may be maintained substantially constant, whereby the printing quality of the print head may be further enhanced.
To avoid deterioration of the printing quality due to a variation in the displacement amount of the piezoelectric element due to the temperature variation or other factors during a printing operation, it is proposed to detect the printing pressure by operating the piezoelectric element for this particular purpose rather than for effecting a printing action, so that the level of the voltage applied to the piezoelectric element for printing actions may be controlled based on the detected printing pressure, so as to maintain the printing pressure substantially constant.
In the above proposed method, a voltage is applied to the piezoelectric element to detect the printing pressure and determine an optimum level of the printing voltage, prior to an energization of the element with the printing voltage, even if this energization occurs a relatively long non-operating time after the last energization cycle of the piezoelectric element. However, since the printing pressure varies with an amount of displacement of the piezoelectric element, the detected printing pressure includes an error if the actual amount of residual strain of the element immediately before the application of the voltage for the detection of the printing pressure includes an error. In this case, the determined optimum printing voltage necessarily includes an error, causing deterioration of the printing quality.
Nevertheless, this method may be combined with the method of the present invention. In this case, the printing voltage may be adequately determined without an error, so that the printing pressure may be maintained at an optimum level, assuring improved quality of printing by the piezoelectric element.
The second object of the invention indicated above may be attained according to another aspect of the present invention, which provides an apparatus driven by a piezoelectric actuator including a piezoelectric element and a control device for controlling an operation of said piezoelectric element, the piezoelectric element undergoing a strain whose amount varies with a voltage applied thereto, and having a residual strain left after removal of the voltage, such that a difference between a pre-energization amount and a post-energization amount of the residual strain before and after an energization of the piezoelectric element with the voltage varies depending upon a hysteresis of the piezoelectric element before the energization, the control device including preliminary energization means for effecting at least one preliminary energization of the piezoelectric element, prior to a primary energization cycle of the piezoelectric element, at least where the difference between the pre- and post-energization amounts of the residual strain of the piezoelectric element is equal to a predetermined value or larger. The primary energization cycle includes at least one primary energization of the piezoelectric element for attaining a desired function..
The instant apparatus provides substantially the same advantages as the method of the invention described above.
The preliminary energization means may comprise means for effecting a preliminary energization of the piezoelectric element upon application of power to the control device.
Alternatively the preliminary energization means may comprise means for determining whether a command for the primary energization cycle of the peizoelectric element is received by the control device, or not, and means responsive to the command, for effecting a preliminary energization of the piezoelectric element, prior to the primary energization cycle.
In a further alternative form of the apparatus, the preliminary energization means comprises: a timer for measuring a time duration between a moment of completion of the last primary energization cycle of the piezoelectric element and a moment of commencement of the present primary energization cycle of the piezoelectric element; means for determinining whether the time duration measured by the timer is equal to tor larger than a predetermined value, or not; and selective control means for effecting a preliminary energization of the piezoelectric element prior to the present primary energization cycle, if the time duration is equal to or larger than the predetermined value, and inhibiting the preliminary energization if the time duration is smaller than the predetermined value.
In a still further form of the apparatus of the invention, the preliminary energization means comprises: time measuring means for measuring an energization time of the primary energization cycle of the piezoelectric element; memory means for storing the energization time measured by the time measuring means; and selective control means for effecting a preliminary energization of the piezoelectric element prior to the primary energization cycle of the piezoelectric element, if the energization time stored in the memory means at a moment of commencement of the primary energization cycle of the piezoelectric element is equal to or larger than a predetermined value, and inhibiting the preliminary energization if the energization time is smaller than the predetermined value.
In a yet further form of the apparatus, the preliminary energization means comprises: a temperature measuring means for measuring a temperature of the piezoelectric element; and selective control means for effecting a preliminary energization of the piezoelectric element prior to the primary energization cycle of the piezoelectric element if the temperature of the piezoelectric element measured by the temperature measuring means is equal to or larger than a predetermined value, and inhibiting the preliminary energization if the temperature exceeds the predetermined level.
In another form of the instant apparatus, the preliminary energization means comprises: temperature measuring means for measuring a temperature of the piezoelectric element at a moment when the primary energization cycle of the piezoelectric element is completed; memory means for storing the temperature measured by the temperature measuring means; and selective control means for effecting a preliminary energization of the piezoelectric element prior to the primary energization cycle of the piezoelectric element if the temperature stored in the memory means at a moment of commencement of the primary energization cycle of the piezoelectric element is equal to or higher than a predetermined level, and inhibiting the preliminary energization if the temperature stored in the memory means is lower than the predetermined value.
In a further form of the apparatus, the preliminary energization means comprises: first temperature measuring means for measuring a current temperature of the piezoelectric element at a moment of commencement of the primary energization cycle of the piezoelectric element; second temperature measuring means for measuring a last temperature of the piezoelectric element at a moment of completion of the primary energization cycle of the piezoelectric element; memory means for storing the last temperature of the piezoelectric element measured by the second temperature measuring means; and selective control means for effecting a preliminary energization of the piezoelectric element prior to the primary energization cycle if a difference between the last temperature stored in the memory means and the current temperature measured by the first temperature measuring means is equal to or higher than a predetermined level, and inhibiting the preliminary energization if the difference is lower than the predetermined level.
Thus in at least some cases an initial energisation is began, and it is determined whether that is to be a preliminary, non operational, energisation or the primary energisation.
The invention will be better understood from the following description, given by wayof example onlv with reference to the accompanying drawings in which:
Fig. 1 is a schematic block diagram showing an electric circuit of printers which respectively incorporate a first and a second embodiment of the present invention;
Figs. 2 and 3 are flow charts respectively illustrating control programs for controlling the printers incorporating the first and second embodiments of the invention;
Fig. 4 is a schematic block diagram showing an electric circuit of printers which respectively incorporate a third and a fourth embodiment of the invention;
Figs. 5 and 6 are flow charts respectively illustrating control programs for controlling the printers incorporating the third and fourth embodiments of the invention;;
Fig. 7 is a schematic block diagram showing an electric circuit of printers which respectively incorporate a fifth, a sixth and a seventh embodiment of the invention;
Figs. 8, 9 and 10 are flow charts respectively illustrating control programs of the printers incorporating the fifth, sixth and seventh embodiments of the invention;
Fig. 11 is a schematic side elevational view of one form of an piezoelectric actuator, as used in a dot-matrix impact print head;
Fig. 12 is a graph indicating the amount of residual strain of a piezoelectric element which varies with temperature;
Fig. 13 is a graphical representation illustrating a change in the amount of displacement of the piezoelectric element of Fig. 12 used as a drive source for a dot-matrix impact print head, where a printer having the print head is controlled according to a conventional method; ;
Fig. 14 is a graph illustrating the amount of residual strain of a piezoelectric element which varies with time; and
Fig. 15 is a graphical representation illustrating a change in the amount of displacement of the piezoelectric element of Fig. 14 used as a drive source for a dot-matrix impact print head, where a printer having the print head is controlled according to a conventional method.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The presently preferred embodiments which will be described in detail by reference to the accompanying drawings are applied to printers having a print head which incorporates a piezoelectric actuator. Such printers are typical examples of apparatus or instruments using a piezoelectric actuator to which the principle of the invention is applicable. The printer associated with each illustrated embodiment is indicated generally at 10, in
Fig. 1, for example. The printer 10 includes a piezoelectric element 12 as a drive source for the print head, a driver 14 for the piezoelectric element 12, and a driver controller 16 which consists principally of a computer. The driver controller 16 is connected to a suitable printer control device.After the printer control device applies a START signal to the driver controller 16, the printer control device supplies the controller 16 with printer control signals, which include a series of print data which are necessary to operate the printer 10 so that the print head prints a plurality of characters.
Referring first to the flow chart of Fig. 2, the first embodiment of the invention will be described.
Upon application of power to the printer 10, the control flow first goes to step S10 in which the driver 14 is supplied with a preliminary energization signal. This preliminary energization signal is provided to apply a preliminary voltage to the piezoelectric element 12 for a given period of time. The conditions for the preliminary energization of the element 12, such as the level of the preliminary voltage, and the rise time and duration of the preliminary energization signal are determined such that the piezoelectric element 12 is energized to effect a maximum amount of displacement thereof, so that the actual amount of residual strain of the piezoelectric element 12 after the removal of the preliminary voltage coincides with the nominal value that varies with various conditions such as the temperature of the element 12.As described below, an error of the actual amount of residual strain of the element 12 from the nominal value is completely eliminated after the preliminary voltage is applied and removed to and from the element 12.
Then, the control flow goes to step Sll to determine whether a START signal from the printer control device is received by the driver controller 16, or not.
Upon generation of the START signal, step S12 is executed to apply a printing energization signal to the driver 14, according to a control signal from the printer control device. The driver 14 which has received the printing energization signal applies a printing voltage to the piezoelectric element 12 for a controlled period, under the conditions necessary for enabling the piezoelectric element 12 to be suitably energized for a printing action. During a printing operation initiated by the START signal, such printing voltages are applied to and removed from the piezoelectric element 12, usually a multiplicity of times, at relatively short intervals.After this printing operation with the printing voltages applied to the piezoelectric element 12 is completed, the control flow goes to step S13 wherein the printer 10 is automatically turned off.
It will be apparent from the above explanation that the preliminary voltage is applied to the piezoelectric element 12 upon application of power to the printer 10, prior to the application of the printing voltages to the element 12 for a primary energization cycle to attain an intended purpose, i.e., to effect an actual printing operation. As a result, an error of the actual residual strain of the piezoelectric element 12 from the nominal value prior to the printing action may be eliminated, irrespective of the actual amount of the residual strain of the element 12 before energization of the element 12 for the printing operation. Therefore, the application of the preliminary voltage permits the piezoelectric element 12 to have the nominal amount of strain or displacement upon application of the printing voltage thereto.
In the present embodiment, power is automatically removed from the printer 10, at the end of the printing operation initiated by each START signal, and the operator must turn on the printer 10 piror to each printing operation. In other words, the present embodiment is adapted to apply the preliminary voltage to the piezoelectric element 12, to eliminate the error of the residual strain, upon each application of power to the printer 10, i.e., before each primary energization cycle of the element 12 for effecting each printing operation. The following embodiments, however, may be adapted such that the printer 10 will not be automatically turned off upon completion of each printing operation, unless the operator manipulates the printer to remove power therefrom, as in an ordinary printer.
The second embodiment of the invention will be described, referring to the flow chart of Fig. 3.
Initially, step 520 is executed to determine whether a START signal is received by the driver controller 14, or not. Upon generation of the "START" signal from the printer control device, the control flow goes to step S21 in which a preliminary energization signal is applied to the driver 14, whereby the error of the actual amount of residual strain of the piezoelectric element 14 is eliminated. Then, in step 522, the printing voltages are applied to the piezoelectric element 12 for energization thereof for a printing operation. The control flow then returns to step S20, to wait for the generation of the next "START" signal.
It will be understood from the above explanation that the error of the actual amount of residual strain of the piezoelectric element 12 is eliminated immediately after the generation of each START signal or immediately prior to each primary energization cycle of the element 12 for a printing operation, irrespective of the actual amount of residual strain. Subsequently, printing voltages are applied to the piezoelectric element 12 for effecting a printing operation.
The third embodiment of the invention will be described. In the printer 10 to which the present embodiment is applied, a timer 18 is connected to the driver controller 16, as indicated in Fig. 4.
An operation of the printer 10 controlled according to the present embodiment will be described by reference to the flow chart of Fig. 5. Initially, step S30 is implemented to determine whether a START signal is received by the driver controller 16. Upon generation of the "START" signal, step S31 is executed to turn off the timer 18, which was turned on by the controller 16 when the energization of the element 12 for the last printing action was completed. Namely, the value of the timer 18 at the moment when the timer is turned off in step S31 represents a time duration "t" between the moment of completion of the last printing operation (last primary energization cycle of the element 12), and the moment of generation of the current "START" signal (i.e., moment of commencement of the present primary energization cycle of the element 12).The control flow then goes to step S32 to determine whether the time duration "t" is equal to or greater than a predetermined value.
The predetermined value of the time duration "t" is determined such that a difference in temperature of the piezoelectric element 12 between the moment of completion of the last printing operation and the beginning of the present printing operation is large enough to cause the error of the actual amount of residual strain of the element 12 to exceed a predetermined amount, during that predetermined value of the time duration "t". Therefore, the instant embodiment is adapted such that if the time duration "t" is equal to or larger than the predetermined value, step S32 is followed by step S33 in which a preliminary voltage is applied to the driver 14, to preliminarily energize the piezoelectric element 12, so that the error of the residual strain of the element 12 is eliminated.
Subsequently, step S34 is implemented to effect a printing operation by energizing the piezoelectric element 12 with printing voltages applied thereto. Upon completion of this primary energization cycle, the timer 18 is turned on to start measuring the time duration "t". Then, the control flow goes back to step S30.
It will be understood from the above description that the present embodiment is adapted such that the amount of error of the residual strain of the element 12 from the nominal value is estimated based on the time duration "t", on the assumption that the ambient temperature of the element 12 is kept constant, and such that the preliminary voltage is applied to the driver 14 to eliminate the error of the residual strain prior to a printing operation, only when the measured time duration "t" becomes equal to the predetermined value.
The fourth embodiment of the present invention will be described. In this embodiment, the printer 10 has the same arrangement as the third embodiment, as shown in
Fig. 4.
The operation of the printer 10 controlled according to the present embodiment is effected as illustrated in the flow chart of Fig. 6. Initially, step
S40 is executed to determine whether a START signal is received by the driver controller 16. Upon generation of the "START" signal, the control flow goes to step S41 to determine whether an energizing time " T " of the piezoelectric element 12 in the last printing operation is equal to or larger than a predetermined time. This energizing time " T" is measured and stored in steps S44,
S45 and S46 which follow step S43 wherein the element 12 is energized for a printing operation, with printing voltages applied thereto.
In the present embodiment, the temperature of the piezoelectric element 12 at the end of the last energization cycle is estimated based on the measured energization time "T " of the element 12 in the last primary energization cycle, on the assumption that the ambient temperature is held constant. The amount of errror of the residual strain of the piezoelectric element 12 from the nominal value immediately before the present energization cycle is estimated based on the estimated temperature of the piezoelectric element 12, and according to a known relationship between the temperature and the amount of residual strain of the element 12.The predetermined value of the energization time " or " is determined such that a difference in temperature of the piezoelectric element 12 between the moments of the last and present energization cycles of the element 12 is large enough to cause the error of the actual residual strain of the element 12 from the nominal value to exceed a predetermined value, during that energization time. Therefore, the instant embodiment is adapted such that if the measured energization time "t" is equal to or larger than the predetermined value, step S42 is implemented to apply a preliminary energization signal to the driver 14, so that a preliminary voltage is applied to the piezoelectric element 12, for preliminary energization of the element 12, for eliminating the error of the residual strain of the element 12.
Then, step S43 is executed to apply printing voltages to the piezoelectric element for primary energization thereof for a printing operation, and at the same time step S44 is executed to turn on the timer 18, thereby starting the measurement of the energization time '' ". Step S45 is provided to determine whether the energization of the element 12 for the present printing operation is completed, or not. Upon completion of the energization of the element 12, step S45 is followed by step S46 wherein the timer 18 is turned off, and the measured energization time "z" is stored in a memory of the driver controller 16.
The fifth embodiment of the invention will be described. The printer 10 to which the present embodiment applies includes a temperature sensor 20 connected to the driver controller 16. The temprature sensor 20 is adapted to detect a temperature "H" of the piezoelectric element 12 per se or the ambient temperature "H" of the element 12 (both of which are hereinafter referred to as temperature "H" of the piezoelectric element 12).
The operation of the printer 10 associated with the present embodiment will be described, by reference to the flow chart of Fig. 8. Initially, step S50 is implemented to determine whether a START signal is received by the driver controller 16. Upon generation of the START signal, step S51 is executed to determine whether the temperature "H" of the piezoelectric element 12 currently measured by the temperature sensor 20 is equal to or lower than a predetermined level, or not.
In the present embodiment, the error of the residual strain of the piezoelectric element 12 immediately prior to the primary energization cycle for the present printing action is estimated based on the current temperature "H" of the element 12, and according to a known relationship between the temperature "H" and the amount of residual strain of the element 12, on the assumption that the temperature of the element 12 after completion of the energization cycle is held contant. The predetermined value of the temperature "H" is determined such that the amount of error of the residual strain of the piezoelectric element 12 exceeds a predetermined value if the measured temperature "H" is equal to or lower than that predetermined level. Namely, the present embodiment is adapted such that if the measured temeprature "H" is equal to or lower than the predetermined level, step S52 is implemented to apply a preliminary energization signal to the driver controller 16, to apply a preliminary voltage to the piezoelectric element 12, so that the error of the residual strain of the element 12 is eliminated.
Subsequently, step S53 is executed to apply printing voltages to the element 12 for primary energization thereof for a printing operation. Then, the control flow goes back to step S50.
The sixth embodiment of the invention will be described. The printer 10 to which the present embodiment applies has the same arrangement as the fifth embodiment, as shown in Fig. 7.
The operation of the printer 10 associated with the present embodiment will be described referring to the flow chart of Fig. 9. Initially, step S60 is executed to determine whether a START signal is received by the driver controller 16, or not. Then, the control flow goes to step S61 to determine whether a temperature He" of the piezoelectric element 12 which was measured at the end of the last energization cycle is equal to or higher than a predetermined level. This temperature "He" was measured by the temperature sensor 20, and stored in steps S64 and S65 which follow step S63 for energization of the element 12 for a printing operation.
In the present embodiment, the error of the residual strain of the piezoelectric element 12 immediately prior to the primary energization for the current printing action is estimated based on the temperature "He" of the element 12 at the end of the last energization cycle, and according to a known relationship between the temperature "He" and the amount of the residual strain, on the assumption that the ambient temperature of the element 12 is held constant. The predetermined value of the temperature "He" is determined such that the amount of error of the residual strain of the piezoelectric element 12 exceeds a predetermined value if the measured temperature "He" is equal to or higher than that predetermined level.Namely, the present embodiment is adapted such that if the measured temeprature "He" is equal to or higher than the predetermined level, step S62 is implemented to apply a preliminary energization signal to the driver controller 16, to apply a preliminary voltage to the piezoelectric element 12, so that the error of the residual strain of the element 12 is eliminated.
Subsequently, step S63 is executed to apply printing voltages to the element 12 for primary energization thereof for a printing operation. Step S63 is followed by step S64 to check if the primary energization cycle of the element 12 for the printing action is completed, or not. Upon completion of the printing energization cycle of the element 12, the control flow goes to step S65 wherein the driver controller 16 stores in its memory the temperature "He" currently measured by the sensor 20.
The seventh embodiment of the invention will be described. The printer 10 to which the present embodiment applies has the same arrangement as the sixth embodiment.
The operation of the printer 10 associated with the present embodiment will be described by reference to the flow chart of Fig. 10. Initially, step S70 is executed to determine whether a START signal is received by the driver controller 16, or not. Upon reception of the START signal, the driver controller 16 executes step S71 wherein a current temperature "Hs" of the piezoelectric element 12 measured by the sensor 20 is stored in the memory. This memory also stores the temperature "He" of the element 12 which was measured and stored in steps S76 and S77, at the end of the last primary energization cycle of the element 12 for the last printing operation.Step S71 is followed by step S72 wherein a difference AH between the last and current measurements "He" and "Hs" of the temperature of the element 12 is calculated. Step S72 is followed by step S73 to determine whether the difference AH is equal to or larger than a predetermined value, or not.
In the present embodiment, the error of the residual strain of the piezoelectric element 12 immediately prior to the present primary energization cycle is estimated based on the temperature difference tH, and according to a known relationship between the difference tH and the residual strain of the element 12. The predetermined value of the difference AH is determined such that the amount of error of the residual strain exceeds a predetermined value if the difference AH is equal to or larger than the predetermined value of difference.Namely, the present embodiment is adapted such that if the calculated temperature difference tH is equal to or larger than the predetermined value, step S74 is implemented to apply a preliminary energization signal to the driver 14, to apply a preliminary voltage to the piezoelectric element 12 for preliminary energization for eliminating the error of the residual strain. Step S74 is followed by step S75 wherein printing voltages are applied to the element 12 for the printing operation. Steps S76 and S77 are executed to store the temperature "He" of the element 12 at the time when the printing energization of the element 12 in step
S76 is completed.
While the preliminary energization signal for preliminarily energizing the piezoelectric element 12 is generated by the driver controller 16 of the printer 10 in the illustrated embodiments described above, this signal may be generated by the printer control device, or a device exclusively provided for applying the signal to the driver 14.
It will be understood that the preliminary energization of the piezoelectric element 12 according to the principle of the present invention should not result in an actual printing action. To avoid this, the preliminary voltage may be applied to the piezoelectric element 12 such that the preliminary voltage is increased at a lower rate than usual, so as to prevent the printing pressure from exceeding a predetermined limit. Alternatively, the preliminary voltage may be applied to the element 12, when the print head carrying the element 12 is moved from the recording medium, as in the zeroing movement of a carriage with the print head, or when a print ribbon or the print head is spaced away from the surface of the recording medium.
While the present invention has been described in its presently preferred embodiments, for illustrative purpose only, it is to be understood that the invention may be embodied with various improvements and changes, which may occur to those skilled in the art.
Claims (14)
1. A method of controlling an apparatus which is driven by a piezoelectric actuator including a piezoelectric element whose strain varies with a voltage applied thereto and which has a residual strain left after removal of said voltage, such that a difference between a pre-energization amount and a post-energization amount of the residual strain before and after an energization of the piezoelectric element with said voltage varies depending upon a hysteresis of the piezoelectric element before said energization, comprising the step of effecting at least one preliminary energization of said piezoelectric element, prior to a primary energization cycle of said piezoelectric element, at least where said difference between said pre-energization and post-energization amounts of said residual strain of said piezoelectric element is equal to a predetermined value or larger, said primary energization cycle including at least one primary energization of said piezoelectric element for attaining a desired function.
2. A method according to claim 1, wherein said step of effecting at least one preliminary energization of said piezoelectric element comprises effecting a preliminary energization of said piezoelectric element before and each time a first primary energization of said primary energization cycle of the piezoelectric element takes place.
3. A method according to claim 1 or 2 further comprising a step of determining whether said difference between said pre-energization and post-energization amounts of said residual strain of said piezoelectric element is equal to said predetermined value or larger, or not, and wherein said step of effecting at least one preliminary energization of said piezoelectric element comprises effecting a preliminary energization of said piezoelectric element only where said difference of the residual strain before and after said primary energization cycle is expected to exceed said predetermined value.
4. An apparatus driven by a piezoelectric actuator including a piezoelectric element and a control device for controlling an operation of said piezoelectric element, said piezoelectric element undergoing a strain whose amount varies with a voltage applied thereto, and having a residual strain left after removal of said voltage, such that a difference between a pre-energization amount and a post-energization amount of the residual strain before and after an energization of the piezoelectric element with said voltage varies depending upon a hysteresis of the piezoelectric element before said energization,
said control device including preliminary energization means for effecting at least one preliminary energization of said piezoelectric element, prior to a primary energization cycle of the piezoelectric element, at least where said difference between pre-energization and post-energization amounts of said piezoelectric element is equal to a predetermined value or larger, or not, said primary energization cycle including at least one primary energization of said piezoelectric element for attaining a desired function.
5. An apparatus according to claim 4, wherein said preliminary energization means comprises means for effecting a preliminary energization of said piezoelectric element upon application of power to said control device.
6. An apparatus according to claim 4, wherein said preliminary energization means comprises means for determining whether a command for said primary energization cycle of said peizoelectric . element is received by said control device, or not and further comprises means responsive to said command, for effecting a preliminary energization of said piezoelectric element, prior to said primary energization cycle.
7. An apparatus according to claim 4, wherein said preliminary energization means comprises:
a timer for measuring a time duration between a moment of completion of the primary energization cycle of said piezoelectric element and a moment of commencement of the primary energization cycle of the piezoelectric element;
means for determinining whether said time duration measured by said timer is equal to a predetermined value or larger, or not; and
selective control means for effecting a preliminary energization of said piezoelectric element prior to said primary energization cycle, if said time duration is equal to said predetermined value or larger, and inhibiting said preliminary energization if said time duration is smaller than said predetermined value.
8. An apparatua according to claim 4, wherein said preliminary energization means comprises:
time measuring means for measuring an energization time of the primary energization cycle of said piezoelectric element;
memory means for storing said energization time measured by said time measuring means; and
selective control means for effecting a preliminary energization of said piezoelectric element prior to the primary energization cycle of the piezoelectric element, if said energization time stored in said memory means at a moment of commencement of the primary energization cycle of the piezoelectric element is equal to a predetermined value or larger, and inhibiting said preliminary energization if said energization time is smaller than said predetermined value.
9. An apparatus according to claim 4, wherein said preliminary energization means comprises:
a temperature measuring means for measuring a temperature of said piezoelectric element; and
selective control means for effecting a preliminary energization of said piezoelectric element prior to said primary energization cycle of the piezoelectric element if said temperature of the piezoelectric element measured by said temperature measuring means is equal to a predetermined level or lower, and inhibiting said preliminary energization if said temperature exceeds said predetermined level.
10. An apparatus according to claim 4, wherein said preliminary energization means comprises:
temperature measuring means for measuring a temperature of said piezoelectric element at a moment when the primary energization cycle of the piezoelectric element is completed;
memory means for storing the temperature measured by said temperature measuring means; and
selective control means for effecting a preliminary energization of said piezoelectric element prior to the primary energization cycle of the piezoelectric element if said temperature stored in said memory means at a moment of commencement of the primary energization cycle of the piezoelectric element is equal to a predetermined level or higher, and inhibiting said preliminary energization if said temperature stored in said memory means is lower than said predetermined value.
11. An apparatus according to claim 4, wherein said preliminary energization means comprises:
first temperature measuring means for measuring a current temperature of said piezoelectric element at a moment of commencement of the primary energization cycle of the piezoelectric element;
second temperature measuring means for measuring a last temperature of said piezoelectric element at a moment of completion of the primary energization cycle of the piezoelectric element;
memory means for storing said last temperature of said piezoelectric element measured by said second temperature measuring means; and
selective control means for effecting a preliminary energization of said piezoelectric element prior to said primary energization cycle if a difference between said last temperature stored in said memory means and said current temperature measured by said first temperature measuring means is equal to a predetermined level or higher, and inhibiting said preliminary energization if said difference is lower than said predetermined level.
12. Methods of controlling an apparatus which is driven by a piezoelectric actuator substantially as hereinbefore described with reference to the accompanying drawings.
13. An apparatus driven by a piezoelectric actuator and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
14. Apparatus according to any one of claims 4 to 11 or 13 which is a printer.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63112895A JPH01283888A (en) | 1988-05-10 | 1988-05-10 | Operating method for piezoelectric actuator loaded device |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8910391D0 GB8910391D0 (en) | 1989-06-21 |
| GB2219145A true GB2219145A (en) | 1989-11-29 |
| GB2219145B GB2219145B (en) | 1992-08-26 |
Family
ID=14598194
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8910391A Expired - Fee Related GB2219145B (en) | 1988-05-10 | 1989-05-05 | Apparatus having piezoelectric actuator,and method of controlling the piezoelectric element |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPH01283888A (en) |
| GB (1) | GB2219145B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6175180B1 (en) * | 1998-03-27 | 2001-01-16 | Optikon 2000 S.P.A. | Method for optimizing the drive of a piezoelectric actuator, in particular for phacoemulsifier devices, by dynamic detection of its eletromechanical characteristics and devices based thereupon |
| WO2001023736A1 (en) * | 1999-09-29 | 2001-04-05 | Siemens Aktiengesellschaft | Method for initialising an electro-mechanical converter |
| EP1138910A1 (en) * | 2000-04-01 | 2001-10-04 | Robert Bosch GmbH | Control of the polarization of piezoelectric elements before each first injection to achieve optimized starting conditions |
| EP1139441A1 (en) * | 2000-04-01 | 2001-10-04 | Robert Bosch GmbH | Method and apparatus for controlling system parameters, particularly in fuel injection systems |
| GB2380625A (en) * | 2001-08-31 | 2003-04-09 | Ngk Insulators Ltd | Restoration of the working displacement of piezoelectric actuators in a display |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4314174A (en) * | 1980-03-25 | 1982-02-02 | Litton Systems, Inc. | Piezoelectric transducer drive having temperature compensation |
| EP0124250A1 (en) * | 1983-03-31 | 1984-11-07 | Kabushiki Kaisha Toshiba | Displacement generation device |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS61180581A (en) * | 1985-02-04 | 1986-08-13 | Canon Inc | Controlling method for piezoelectric effect element |
| JPS62217880A (en) * | 1986-03-18 | 1987-09-25 | Omron Tateisi Electronics Co | Driving method for piezoelectric actuator |
| JPS62235788A (en) * | 1986-04-07 | 1987-10-15 | Hitachi Ltd | Driving method for electrostrictive element |
-
1988
- 1988-05-10 JP JP63112895A patent/JPH01283888A/en active Pending
-
1989
- 1989-05-05 GB GB8910391A patent/GB2219145B/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4314174A (en) * | 1980-03-25 | 1982-02-02 | Litton Systems, Inc. | Piezoelectric transducer drive having temperature compensation |
| EP0124250A1 (en) * | 1983-03-31 | 1984-11-07 | Kabushiki Kaisha Toshiba | Displacement generation device |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6175180B1 (en) * | 1998-03-27 | 2001-01-16 | Optikon 2000 S.P.A. | Method for optimizing the drive of a piezoelectric actuator, in particular for phacoemulsifier devices, by dynamic detection of its eletromechanical characteristics and devices based thereupon |
| WO2001023736A1 (en) * | 1999-09-29 | 2001-04-05 | Siemens Aktiengesellschaft | Method for initialising an electro-mechanical converter |
| US6532942B2 (en) | 1999-09-29 | 2003-03-18 | Siemens Aktiengesellschaft | Pre-treatment method for an electromagnetic transducer |
| EP1138910A1 (en) * | 2000-04-01 | 2001-10-04 | Robert Bosch GmbH | Control of the polarization of piezoelectric elements before each first injection to achieve optimized starting conditions |
| EP1139441A1 (en) * | 2000-04-01 | 2001-10-04 | Robert Bosch GmbH | Method and apparatus for controlling system parameters, particularly in fuel injection systems |
| GB2380625A (en) * | 2001-08-31 | 2003-04-09 | Ngk Insulators Ltd | Restoration of the working displacement of piezoelectric actuators in a display |
Also Published As
| Publication number | Publication date |
|---|---|
| GB8910391D0 (en) | 1989-06-21 |
| GB2219145B (en) | 1992-08-26 |
| JPH01283888A (en) | 1989-11-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19940505 |