JPH0939231A - Printer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a constitution of a piezoelectric control means of a printer simple and low costed. SOLUTION: In a printer wherein printing elements are composed of a plurality of piezoelectric elements 91 -9n , a driving control means 20 composed of a voltage application means 30 which applies drive voltage to a plurality of piezoelectric elements 91 -9n , and a piezoelectric element selection means 14 which selects whether or not drive voltage is applied to each piezoelectric element, is provided. Then, a high voltage power source HV, a charging resistance Rc, a discharging resistance Rd, charge switching elements TR1-n applying and controlling driving voltage from the high voltage power source to the piezoelectric element, a discharge switching element TRc, and a discharge control pulse generating means 31 which generates a charge control pulse signal and a discharge control pulse signal, are provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printer using a piezoelectric element, and more particularly to a printer in which a printing element is composed of a plurality of piezoelectric elements.

[0002]

2. Description of the Related Art As printers, there are printers shown in FIGS. This printer is an ink jet type printer, and is driven by a feed screw 4 (A in FIG. 8) to a sheet 7 wound around a platen 5 and fed (direction C in FIG. 8).
In the B direction), the ink 6 is ejected from the print head 1 provided on the carrier 2 guided by the guide shaft 3 to print necessary characters and the like on the paper 7.

[0003] print head 1 for use in such printers is for ejecting ink from the nozzles 10 ₁ to 10 _n that are opened in the nozzle plate 11 as shown in FIG. 9, for example, the nozzle 10 ₁ to 10 _n The nozzle plate 11 having the above-described structure, the predetermined flow paths 12 _{1 to} 12 _n, and the flow path plate 14 having the pressure chambers 13 _{1 to} 13 _n are joined to each other, and a driving voltage is applied to the piezoelectric elements 9 _{1 to} 9 _n . In this way, the inner volume of the pressure chambers 13 _{1 to} 13 _n is changed to eject the ink 6 from the nozzles 10 ₁ to 10 _n .

Piezoelectric elements 9 ₁ -provided in the print head 1
In _order to drive 9 _n , it is necessary to apply a drive voltage as shown in FIG. 11 to each piezoelectric element as a predetermined drive voltage 9 _{1 to} 9 _n .

In such a printer, due to changes in ink viscosity due to environmental temperature, print head temperature, etc., differences in the colors and types of ink used, and differences in printing paper, the particles of ejected ink are The amount of ink is controlled. Therefore, in order to change the ink amount of the ejected ink particles, the drive waveform for driving the print head ejecting the ink is changed according to the required ink amount.

Conventionally, for example, the control of the drive waveform of the print head of the ink jet printer using the piezoelectric element as the print element is performed as follows.

First, the voltage application means for applying a drive voltage to the common electrode of the piezoelectric element will be described. The waveform of the drive voltage applied to the piezoelectric elements 9 _{1 to} 9 _n of the print head 1 in this voltage applying means is a digital element ROM having a plurality of waveforms according to the difference in temperature and ink printing paper.
It is stored in the waveform table 11 composed of the like. A host device (not shown) selects a drive waveform based on a print command depending on the environment and the ink sheet used, for example, n
A bit selection signal is given to the waveform table 11.

In addition to the selection signal, the host device inputs print data to the piezoelectric element selection circuit. Print data, a clock, and a latch signal are input to the piezoelectric element selection circuit via the shift register 12, the latch circuit 13, etc., serially input print data is converted into parallel, and the latch signal is used as a trigger to select the piezoelectric element. It is input to the piezoelectric element selection circuit 14, which is a means.

As such a piezoelectric element selection circuit 14, the one shown in FIG. 10 is used. This circuit is
Common electrode 9a is applied to the side voltage, opposite to the individual electrode 9b ₁ ~9b _n side or left floating or grounded the piezoelectric elements 91 _to 93 of the piezoelectric element from said voltage applying means
The voltage is selectively applied to _n . That is, the piezoelectric elements 9 ₁ to 9 _n, the transistors 15 ₁ to 15 _n and the diode 16 ₁ ~ 16 _n are provided in parallel, each transistor 15 ₁ to 15 _n as a switching element, the piezoelectric elements 9 ₁ - It is selected whether or not the drive voltage is applied to 9 _n .

According to such a drive control means, after the data transfer of all the piezoelectric elements is completed, the table access circuit 1
9 to the DAC (DA converter) 17 to provide m-bit data of the waveform table to the DAC 17
Drive waveform is converted into analog voltage by
Then, current / voltage amplification is performed and a drive voltage is applied to the piezoelectric elements 9 _{1 to} 9 _n . Then, in the piezoelectric element selection circuit 14 on the basis of print data, transistor 15 ₁ to 15 _n corresponding to the nozzle to be printed is turned on, the piezoelectric element corresponding to the nozzle is charged and discharged.

As a result, the piezoelectric element of the print head contracts and expands, sucks and ejects ink, and ejects the ink onto the paper. On the other hand, with respect to the non-printed portion, the transistor of the piezoelectric element selection circuit corresponding to the nozzle is turned off, the piezoelectric element is not charged and discharged, and the ink is not ejected onto the paper.

[0012]

In the conventional printer described above, the drive control means including the voltage applying means and the piezoelectric element selecting means has the following problems.

First, the voltage application means requires a large waveform table corresponding to the temperature of the environment as the waveform table, and since there are many analog parts, the cost is high.

Secondly, in the piezoelectric element selection circuit of this drive control means shown as a conventional example, the scanning waveform generating circuit connected to the common electrode side of the piezoelectric conversion element is basically only one circuit. Also, since the element for nozzle selection is composed of a switching element in which one transistor and one diode are combined so that current can flow in both directions, it can be realized with a small number of parts, but it is connected to the individual electrode side. As the switching element, for example, a commercially available IC for a plasma display, which incorporates a shift register and a register, can be used.

However, the selection of the IC of the piezoelectric element selection circuit is limited in terms of the number of outputs, withstand voltage, etc., and it is difficult to obtain a suitable one in terms of cost and performance. . Therefore, an object of the present invention is to reduce the cost by simplifying the structure of the drive control means of the piezoelectric element.

[0016]

The first means of the present invention is to:
In a printer in which a printing element is composed of a plurality of piezoelectric elements, a voltage applying means for applying a driving voltage to a common electrode of the plurality of piezoelectric elements, and a piezoelectric element selection for selecting whether to apply the driving voltage to each piezoelectric element Drive control means including means, the drive control means is connected in series to the piezoelectric element for each piezoelectric element and a high-voltage power supply for applying a drive voltage to the piezoelectric element, and contributes to charging and discharging of the piezoelectric element. A charging resistor, a discharging resistor that contributes to discharging the piezoelectric element, a charging switching element that controls application of a driving voltage from the high-voltage power source to the piezoelectric element, and a discharging switching that controls discharge of the electric charge charged in the piezoelectric element. A charge control pulse signal of a specified generation pattern is generated from a plurality of kinds of predetermined generation patterns for the element and the charge switching element. A charge control pulse generating means, a printer and a discharge control pulse generating means for generating a discharge control pulse signal of the designated generation pattern from the plurality of types of generating a predetermined pattern on the discharge switching element.

The second means of the present invention is determined by the charging time constant determined by the electrostatic capacitance of the piezoelectric element of the first means and the resistance value of the charging resistance, and the capacitance of the piezoelectric element and the resistance value of the discharge resistance. The discharge time constant is set so that the charge time constant> the discharge time constant. A third means of the present invention is the charging time constant determined by the electrostatic capacity of the piezoelectric element of the first means and the resistance value of the charging resistor, and the discharge time constant determined by the capacitance of the piezoelectric element and the resistance value of the discharging resistance. And are set such that the charging time constant <the discharging time constant.

A fourth means of the present invention is that the piezoelectric element selecting means of the first and second means includes a switching element, and the switching element is a charge switching element.

A fifth means of the present invention is that the voltage applying means of the first, second or third means comprises a switching element, and this switching element is a charge switching element.

According to a sixth aspect of the present invention, the voltage applying means of the first, fourth or fifth means is provided with a discharge switching element conducting to each piezoelectric element and applies the discharge control pulse signal. .

The seventh means of the present invention is the above first, fourth, fifth.
Alternatively, the voltage applying means of the means of 6 has an ambient temperature detecting means of the piezoelectric element, and selects a charge pattern and a discharge pattern according to the output of the detecting means.

The eighth means of the present invention is the above first, fourth, fifth.
Alternatively, the voltage applying means of the means of 6 is a printer characterized by selecting a charging pattern and a discharging pattern according to the type of the recording medium.

A ninth means of the present invention is, in a printer in which a printing element is composed of a plurality of piezoelectric elements, a voltage applying means for applying a drive voltage to a common electrode of the plurality of piezoelectric elements, and a plurality of the piezoelectric elements. Provided is a drive control means comprising a piezoelectric element selection means for selecting whether to apply a drive voltage to each piezoelectric element, and the output format of the switching element of the piezoelectric element selection means is a push-pull format, The drive voltage is also applied to the high voltage power supply side terminal of the switching element.

The tenth means of the present invention is the above first, second,
The printing element of the printer of the means 3, 4, 5, 6, 7, 8 or 9 is of the ink jet type.

An eleventh means of the present invention is the first, second,
The printing element of the printer of the means 3, 4, 5, 6, 7, 8 or 9 is of the wire impact dot type.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a circuit diagram showing a first embodiment of a printer according to the present invention, and FIG. 2 is a timing chart showing its operating state.

In this example, the drive control means 20 has a plurality of
Piezoelectric element 9₁~ 9_nCommon electrode 9a ₁~ 9a_nDrive to
Voltage applying means 30 for applying pressure and respective piezoelectric elements
In the conventional example that selects whether to apply the drive voltage to the
And a piezoelectric element selection circuit 14 similar to the above.

[0028] Then, from the host device in this embodiment, a charge pulse for performing the charging of the piezoelectric element 9 ₁ to 9 _n, and n-bit selection signal designating the charge discharging pattern of the piezoelectric element 9 ₁ to 9 _n, An enable signal, which is a print permission signal,
The print data that specifies the dots to be actually printed and the latch signal that specifies the delimiter point of the print data are input.

Further, the drive control means 20 is supplied with a high voltage power supply HV for applying a drive voltage to the piezoelectric elements 9 _{1 to} 9 _n and a low voltage power supply LV for driving the circuit.

In this embodiment, the drive control means 20
It is to the piezoelectric element 9 ₁ to 9 _n are connected in series with each piezoelectric element 9 ₁ to 9 _n, the charge resistor Rc ₁ to Rc _n contribute to the charging and discharging of the piezoelectric element, the piezoelectric element 9 ₁ to 9 _n and a discharge resistor Rd ₁ ~ Rd _n contribute to the discharge.

The drive control means 20 controls the piezoelectric elements 9 _{1 to} 9 from the high-voltage power supply HV based on the charging pulse signal.
Transistors TRa, T that control the charge applied to _n
Rb, and the piezoelectric element selecting means 14 includes:
A transistor that is a charge switching element that selects the piezoelectric elements 9 _{1 to} 9 _n based on the print data and controls the charging of the piezoelectric elements 9 _{1 to} 9 _n while the charging pulse is in the ON state. TR _{1 to} TR _n and diodes d1 to dn provided in parallel with the transistors TR _{1 to} TR _n are provided.

Further, in the present embodiment, the drive control means 20 supplies the charge control pulse signals of the generation pattern designated by the selection signal from the plurality of types of generation patterns stored in advance to the transistors TR ₁ to TR _n. And a ROM 31 which is a discharge control pulse generating means and a discharge control pulse generating means for generating a discharge control pulse signal in the discharge control transistor TRc.

In this example, the transistor TR
A charging pulse is input to a and TRb through the inverting circuit 33, and the inverting circuits 33 and 34, an AND gate 36, and an AND gate 35 with an inverting circuit are provided to form a circuit.

Further, in this embodiment, as shown in FIG. 2, the host device gives the ROM 31 a selection signal corresponding to the drive waveform determined from the environmental temperature or the type of paper. At this time, as shown in FIG. 2, the print data is serially given to the printer in parallel with this selection signal, and is output in parallel to the piezoelectric element selection circuit 14 using the latch signal as a trigger. When printing is performed, an enable signal and then a charging pulse are raised, and a selection signal is output to the ROM 31.

Then, the ROM 31 selects the piezoelectric element for the designated charge control pulse among the charge control pulses in which plural kinds of data defining "high""H" and "low""L" are stored at a predetermined timing. It occurs in the transistors TR1 to TRn of the circuit 14.

Then, by the latch signal, the piezoelectric elements 9 _{1 to} 9
_The ROM access circuit 32 receiving the enable signal gives a signal to the ROM 31 to the piezoelectric element selection circuit 14 in which the states of all the transistors TR1 to TRn corresponding to _n are determined, and the meniscus in the preparation stage of ink ejection is applied to the pressure chamber side. Transistor TRb connected to the high voltage HV because the charge pulse becomes "H" in order to pull it into
Becomes conductive, and a voltage substantially equal to the high voltage HV is output from its emitter terminal. At the same time, the ROM access circuit 32 starts access to the ROM 31 in synchronization with the charging pulse, and the charging control pulse is given to the piezoelectric element selection circuit 14.

The selected transistor of the piezoelectric element selection circuit 14 is selected.
Jista TR₁~ TR_nIs turned on by the charge control pulse
Repeated off, charging resistance R when the transistor is on
c and piezoelectric element 9₁~ 9_nWhen determined by the capacitance C of
Piezoelectric element 9 with constant τ1₁~ 9 _nIs charged. Charging period
Transistor TR in₁~ TR_nBecomes non-conducting
And the charging current path is cut off, charging is not performed and the piezoelectric element
Child 9₁~ 9_nThe voltage across both ends is retained.

The maximum applied voltage during the charging of the piezoelectric element and the slope of the voltage change are controlled by controlling the time during which the transistors TR ₁ to TR _n are turned on and off.

Then, the charged meniscus is advanced to the nozzle opening side and a charging pulse is applied to eject ink.
When set to L ″, the high-voltage side transistor TRb which has been turned on until now becomes non-conductive, and instead the low-voltage side transistor TRc is repeatedly turned on and off by the discharge control pulse output from the ROM 31, as shown in FIG. The discharge of the electric charges stored in the piezoelectric elements 9 _{1 to} 9 _n is started.

This piezoelectric element 9₁~ 9_nTime constant when discharging
τ2 is the discharge resistance Rd₁~ Rd_nAnd charging resistance Rc₁~ Rc
_nCombined resistance value and piezoelectric element 9₁~ 9_nBy the capacitance C of
Is determined. Further, in this embodiment, the piezoelectric element is selected at the time of discharging.
Transistor TR of circuit 14 ₁~ TR_nConduction / non-conduction
Transistor TR regardless of the state of₁~ TR_nAverage
Discharge through the diodes d1 to dn arranged in rows
Is performed, and each period of conduction / non-conduction of the transistor TRc is performed.
By controlling the piezoelectric element 9₁~ 9_nSlope of voltage change
Is controlled.

In this example, the ink head 1 has a piezoelectric element 9 ₁
Since it is assumed that the lateral effect of ~ 9 _n is used and the discharge period is shorter than the charge period, the charge / discharge time constant is in the relation of charging time> discharging time constant.

On the other hand, when the vertical effect of the piezoelectric elements 9 _{1 to} 9 _n is used, the relationship of the above-mentioned periods is reversed, so that the time constant is set to the relationship of charge time constant <discharge time constant. Further, if the selection signal given to the ROM is changed during the charging period or the discharging period, it is possible to obtain a plurality of arbitrary gradients of voltage changes.

FIG. 3 shows a second embodiment of the present invention.
The present embodiment is different from the first embodiment in that the on / off control at the time of charging is the piezoelectric elements 9 _{1 to} 9 in the first example.
While _n has been performed by the transistor TR ₁ to Tr _n of the selection circuit, in this example another is to on-off control of the transistor TRb high pressure side, the operation is similar to the first embodiment. In the figure, 41 and 42 denote AND gates with an inverting circuit, 43 an inverting circuit, and the same members as those in the first example are designated by the same reference numerals.

Since its operation is the same as that of the first example described above, its detailed description will be omitted.

Next, as a third embodiment of a printer according to the present invention, an element selection circuit having a circuit configuration different from the above-described example will be described.

FIG. 4 shows the circuit configuration, FIG. 5 shows the overall configuration of the printer, and FIG. 6 is a timing chart showing the operation. In this example, the charging voltage for driving the piezoelectric element may be the same as that described in the first or second example, or may be the one described as the conventional example.

Particularly in this example, as shown in FIG. 5, two systems of a charging voltage generating circuit 61 and an amplifier 62 for generating the waveform of the charging signal of the piezoelectric element are provided, and the charging voltage generating circuit 61 is a higher-level device. A charging voltage for monochrome or color is generated according to the instruction from.

The print heads 63 and 64 are monochrome 6
3 and 64 for color are mounted, the corresponding piezoelectric elements 9 _{1 to} 9 _n are also divided into two systems, and the output of each amplifier circuit 62 is output to the monochrome and color piezoelectric elements 9 _{1 to} 9 _n.
Is commonly applied to the common electrode of one system, and is also applied to the high voltage power supply terminal of the piezoelectric element selection circuit 67. In addition, 71 in FIG.
Is a CPU of the printer, 72 is a ROM, 73 is a RAM 74
Is an external interface for connecting a host device, 75 is an interface for controlling the engine of the printer, 76 is a data control circuit for outputting a clock, a latch signal, and data to the piezoelectric element selection circuit, and 77 and 78 are motors for mechanically controlling the printer. A drive circuit and a sensor circuit are shown.

FIG. 4 shows an embodiment of the charging voltage generating circuit according to this embodiment. In this example, it is assumed that MOS transistors are used, and each of the piezoelectric elements 9 _{1 to} 9 _n has four MOSs.
As a push-pull type circuit is formed by the transistors 51, 52, 53, 54 and the two diodes 55, 56, a commercially available driver IC can be used.

Here, when the MOS transistor is used as described above, a parasitic diode exists between the drain and the source of the transistor to which the high voltage power supply is applied, as shown in FIG. In this case, since it is not possible to inject charges from the individual electrode side, it is not possible to apply a constant voltage to the high voltage power supply side terminal. When the high-voltage power supply terminal is used in a floating state, even if the ground side transistor is in a non-conducting state, a charging current that cannot originally flow in the illustrated path flows, and as a result, electric charges are stored in the piezoelectric element and the unselected piezoelectric element. Ink will also be ejected from.
Therefore, by applying a scanning voltage for applying the common electrode to the high-voltage power supply terminal, the anode and cathode of the parasitic diode have the same potential, and the charging current path through the parasitic diode is cut off regardless of the state of the transistor on the ground side. Ink ejection from nozzles that are not selected is prevented.

In this example, the charging voltage generating circuit 61,
The amplifier circuit 62 and the piezoelectric elements 9 _{1 to} 9 _n are provided in two systems so that the load of the amplifier circuit does not become excessive when the number of the piezoelectric elements 9 _{1 to} 9 _n is large. Further, the monochrome head and the color head are not driven simultaneously.

The output terminal of the piezoelectric element selection circuit 50 having the output number corresponding to the number of piezoelectric elements 9 _{1 to} 9 _{n of} one system is connected to the individual electrodes of the piezoelectric elements 9 _{1 to} 9 _n . The piezoelectric element selection circuit 50 includes the shift register and the register as described above, and further has a built-in high-voltage output unit for push-pull output.

As shown in FIG. 6, data is sent from the data control circuit.
The received data is sent to the shift register by the clock.
It is taken in next. Then, the piezoelectric element 9 that is simultaneously driven₁
~ 9 _nCapture the data corresponding to the number n into the shift register
Stop sending the clock. After that, the latch signal
Data held in the shift register
Takes in. When the latch signal is output, the shift
The register can capture the following data. Monochrome
At the time of printing, as shown in Fig. 6, data that is color data
3 and 4 output "0" (On the other hand, in color printing
Data 1 and 2 are "0"). Register output is high voltage output section
Is applied to the gate terminal of the MOS transistor 53.

In this example, in the MOS transistor, the ground-side transistor 54 of the push-pull type output transistors is turned on at the time of printing to bring the individual electrode to the ground level, and at the time of non-printing, the ground side transistor is turned off and the individual electrode is turned off. Floating

On the other hand, the charging voltage generating circuit receives the waveform data during the latch signal and reproduces it. A charging waveform for monochrome or color is generated according to the received waveform data. The waveform of the charging voltage can be generated by the circuit of the first and second embodiments or the circuit shown as the conventional example.

In the above example, the data on the side that does not correspond to the scanning waveform is set to "
Although it is set to 0 ", a disable signal for turning off all the output transistors may be received on the nozzle selection IC side, and at this time, the data on the non-corresponding side may be in any state.

In each of the above-described embodiments, an ink jet printer using a piezoelectric element has been described as an example of the printer, but the piezoelectric element 81 is used as shown in FIG. Can be similarly driven to drive a piezoelectric element of a wire dot type printer that prints ink of an ink ribbon on a paper.

[0058]

According to the present invention, the voltage applying means for applying the drive voltage to the common electrode of the plurality of piezoelectric elements, and the piezoelectric element selecting means for selecting whether or not the drive voltage is applied to each piezoelectric element. Drive control means, and the drive control means comprises a high-voltage power supply for applying a drive voltage to the piezoelectric element, and the piezoelectric element is connected in series for each piezoelectric element to the piezoelectric element. A charging resistor that contributes to charging / discharging, a discharging resistor that contributes to discharging the piezoelectric element, a charging switching element that controls application of a drive voltage from the high-voltage power source to the piezoelectric element, and a charge charged to the piezoelectric element is discharged. A discharge switching element to be controlled, and a charge control element for generating a charge control pulse signal having a specified generation pattern from a plurality of predetermined generation patterns for the charge switching element. Provided with a pulse generation means and a discharge control pulse generation means for generating a discharge control pulse signal of a generation pattern specified from a plurality of types of generation patterns predetermined in the discharge switching element, and a switching element for charging and discharging. Since it is driven by a pulse train whose pulse width and cycle are variable within each charge / discharge time, it is possible to support multiple drive waveforms with a simple circuit configuration without the need for expensive analog parts, making the printer low-cost. There is an effect that can be.

Further, according to the present invention, the charge voltage applied to the common electrode is applied also to the high voltage power supply terminal so that a commercially available driver IC having an output form of push-pull can be used as the piezoelectric element selection circuit. Therefore, it is possible to use a widely used driver IC without using a special IC, and it is possible to widen the selection range of elements and select an appropriate one in terms of cost and performance. Play.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a printer according to the present invention.

FIG. 2 is a timing chart showing the operation of the printer shown in FIG.

FIG. 3 is a diagram showing the configuration of another embodiment of the printer according to the present invention.

FIG. 4 is a diagram showing the configuration of another embodiment of the printer according to the present invention.

5 is a block diagram showing an overall configuration of the printer shown in FIG.

FIG. 6 is a timing chart showing the operation of the printer shown in FIG.

FIG. 7 is a diagram showing a printing element of a wire dot printer to which the present invention is applied.

FIG. 8 is a perspective view showing an overall configuration of an ink jet printer to which the present invention is applied.

FIG. 9 is a partially cutaway perspective view showing a print head of a printer to which the present invention is applied.

FIG. 10 is a block diagram showing a conventional printer.

FIG. 11 is a diagram showing a drive voltage of a print head of a printer to which the present invention is applied.

[Description of Reference Numerals] 9 ₁ to 9 _n piezoelectric elements 14 piezoelectric element selection circuit 31 ROM 32 access circuits Rc ₁ to Rc _n charge resistor Rd ₁ ~ Rd _n discharge resistor TR ₁ to Tr _n transistor (switching element) TRa, TRb, TRc transistor (switching element)

Claims (11)

[Claims] 1. A printer comprising a plurality of piezoelectric elements for forming a printing element, wherein voltage applying means applies a driving voltage to a common electrode of the plurality of piezoelectric elements, and whether or not a driving voltage is applied to each piezoelectric element. Drive control means comprising a piezoelectric element selection means for selecting the piezoelectric element, wherein the drive control means is connected to the piezoelectric element in series for each piezoelectric element and a high voltage power source for applying a drive voltage to the piezoelectric element. Charging resistance that contributes to the charging and discharging of the piezoelectric element, discharging resistance that contributes to the discharging of the piezoelectric element, a charging switching element that controls the application of the drive voltage from the high-voltage power source to the piezoelectric element, and the charge charged to the piezoelectric element. And a discharge switching element for controlling discharge, and a charge control of a generation pattern specified from a plurality of types of generation patterns predetermined for the charge switching element. A discharge control pulse generating means for generating a control pulse signal, and a discharge control pulse generating means for generating a discharge control pulse signal of a generation pattern specified from a plurality of predetermined generation patterns for the discharge switching element. Printer. 2. A charging time constant determined by the capacitance of the piezoelectric element and a resistance value of a charging resistor, and a discharging time constant determined by the capacitance of the piezoelectric element and a resistance value of a discharging resistance are set as a charging time constant>
2. The printer according to claim 1, wherein the relationship is set to be a discharge time constant. 3. A charging time constant defined by the capacitance of the piezoelectric element and a resistance value of a charging resistance and a discharging time constant determined by the resistance value of the piezoelectric element and a resistance of a discharging resistance are set as a charging time constant <
2. The printer according to claim 1, wherein the relationship is set to be a discharge time constant. 4. The printer according to claim 1, 2 or 3, wherein the piezoelectric element selecting means includes a switching element, and the switching element is a charge switching element. 5. The printer according to claim 1, 2 or 3, wherein the voltage applying means includes a switching element, and the switching element is a charge switching element. 6. A printer according to claim 1, 4 or 5, further comprising: a discharge switching element that conducts to each piezoelectric element, and applies the discharge control pulse signal. 7. The printer according to claim 1, 4, 5 or 6, wherein the voltage applying means has means for detecting the ambient temperature of the piezoelectric element, and selects the charging pattern and the discharging pattern according to the output of the detecting means. 8. The printer according to claim 1, 4, 5 or 6, wherein the voltage applying unit selects a charge pattern and a discharge pattern according to the type of the recording medium. 9. A printer comprising a plurality of piezoelectric elements for forming a printing element, a voltage applying means for applying a drive voltage to a common electrode of the plurality of piezoelectric elements, and a plurality of the piezoelectric elements provided on the plurality of piezoelectric elements. A drive control means comprising a piezoelectric element selecting means for selecting whether or not to apply a drive voltage to the piezoelectric element selecting means, and the output format of the switching element of the piezoelectric element selecting means is a push-pull format, and the high-voltage power supply side terminal of the switching element is provided. A printer that also applies a drive voltage. 10. A printer according to claim 1, 2, 3, 4, 5, 6, 7, 8 or 9, wherein the printing element of the printer is of an ink jet type. 11. The printer according to claim 1, 2, 3, 4, wherein the printing element is a wire impact dot system.
The printer according to 5, 6, 7, 8 or 9.