JPH06238898A - Device for controlling ink jet head - Google Patents

Abstract

PURPOSE:To restrain the discharge of unnecessary ink from standby nozzles by controlling the electric potential of proximity electrodes of simultaneously discharging nozzles to be the same electric potential through a simple circuit constitution, and thereby prevent the leakage of electric current. CONSTITUTION:The number of nozzles within the block 1 is in an uneven number, and the first electric potential level of pulse voltage applied on respective electrodes is fixed every electrode. Therefore, the first electric potential level of each electrode 1a, 1c, 1e, 1g initiates from high electric potential, and the first electric potential level of each electrode 1b, 1d, 1f, 1h initiates from low electric potential. Accordingly, among the electrodes constituting nozzles 2a, 2d for effecting simultaneous discharge, the electric potential of the electrodes 1b, 1d not to be adjacent electrodes exhibit the same electric potential, as a result, any leaked electric current does not flow to the nozzles between the electrodes 1b, 1d, and thus the discharge of unnecessary ink form the standby nozzles 2b, 2c can be restrained.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printing apparatus used for output printing of office computers, personal computers and the like, and in particular, a conductive ink is made to flow an energizing current to boil the conductive ink and bubbles generated at that time. The present invention relates to an energization inkjet type inkjet head controller that ejects ink from a nozzle by pressure.

[0002]

2. Description of the Related Art In recent years, ink jet printers have come to be widely used as output printers for office computers because of their quietness during printing. First, a conventional inkjet head controller is shown in FIG.
~ It demonstrates below using FIG. FIG. 7 is a block diagram of a conventional inkjet head controller,

[0003]

[Outer 1]

HLO (high, low, open) logic for outputting data for determining low potential output and open output,
5, the number of pulses is predetermined, the phase of the + pulse signal is 180 degrees ahead of that of the-pulse signal, and +,
A pulse generator for inputting both pulse signals to the HLO logic, 6 is a time division signal T1 for driving the first row nozzles for each block, a time division signal T2 for driving the second row nozzles
The time division signal T3 for driving the nozzles in the third row and the time division signal T4 for driving the nozzles in the fourth row are output to the pulse generator 5, and the time division signals T1, T2 are supplied to each HLO logic.
In synchronization with T3 and T4, print data signals dataA, dataB,
dataC, dataD, dataE, dataF, dataG, dataH, da
taI, dataJ, dataK, dataL and each time division signal T
It is a CPU that outputs both 1, T2, T3, and T4 signals. The block configuration is such that four nozzles 2a, 2b, 2c and 2d are block A, four nozzles 2e, 2f, 2g and 2h are block B and three nozzles 2i, 2j and 2k are block C.
The first row nozzles are the three nozzles 2a, 2e and 2i, and the second row nozzles are the three nozzles 2b, 2f and 2j.
The third row nozzle refers to three nozzles 2c, 2g, and 2k, and the fourth row nozzle refers to two nozzles 2d and 2h.

FIG. 8 is a detailed circuit diagram of the HLO logic 4a. In FIG. 8, 7 selects the signals + PULSE and -PULSE from the pulse generator 5 by T1 and T2 from the CPU 6 and also outputs the high impedance signal HI. Selector circuit, 8 is print data ON, OF from CPU 6
A latch circuit that latches F, and 9 is an AND circuit that takes the logical product of the output LAT from the latch circuit 8 and the output SELOUT from the selection circuit 7, and other HLO logics have the same configuration.

FIG. 9 is an input / output logic diagram of the HLO logic. Further, FIG. 10 is a detailed circuit diagram of the electrode driving device 3a, in which 12 is a high voltage power source that determines the potential of the high potential output of the electrode driving device 3a, and 10 is a high impedance signal HI from the HLO logic 4a. STOP circuit for stopping power supply from power supply 12, 11 is HLO logic 4a
AND circuit for taking the logical product of the high impedance signal HI and the OUT signal from 13; 13 is a resistor; 14 is a transistor;
Is a diode, 16 is an FET (field effect transistor),
FIG. 11 is an input / output logic diagram of the electrode driving device.

Further, FIG. 12 shows the potential of each electrode when + PULSE = H and -PULSE = L and the current flowing through each electrode when + PULSE = H and -PULSE = L are driven by driving the first row nozzle of each block.
FIG. 14 is a potential diagram showing the potential of each electrode when ULSE = L, -PULSE = H and the current flowing through each electrode at that time. FIG. 14 shows the inner nozzles 2a and 2e of the first row nozzle of each block and the second nozzle of each block. A timing chart in which the inner nozzle 2b is ON and the other nozzle groups are all OFF is shown.

The operation of the ink jet head control device configured as described above will be described below. First, since the three nozzles of the first row nozzles 2a, 2e, 2i for each block are driven, the time division signals T1, T2 are output from the CPU 6 as shown in the timing chart of FIG. As a result, + PULSE and -PU, which are out of phase with the pulse generator 5, are synchronized with the falling edges of the time division signals T1 and T2.
The LSE signals are simultaneously output for a predetermined number of pulses of 3. As a result, the + PULSE and -PULSE signals which are out of phase are output to all the HLO logics. In addition, the CPU 6 sends the first data for each block in advance.
Since the row nozzles 2a and 2e are turned on and 2i is turned off, print data is output to each HLO logic in synchronization with the rising edges of the time division signals T1 and T2. Nozzle 2 here
Since a and 2e are ON, data A, data B, data E, and data F are output from the CPU 6 to the HLO logic, and all other data signals are output from OFF.

Since the outputs of the HLO logics 4a and 4e are SEL1 = H and SEL2 = H from the timing chart of FIG. 14, OUT = + PUL according to the input / output logic of FIG.
SE and HI = H are output. Similarly, HLO logic 4
b is SEL1 = H, SE from the timing chart in FIG.
Since L2 = L, OU is output according to the input / output logic of FIG.
T = -PULSE and HI = H are output. The output of all remaining HLO logic is a timing chart.
Since SEL1 = L and SEL2 = L from 14, OU
T = L and HI = L are output. Then, the OUT and HI signals output from each HLO logic are output to each electrode driving device.

Output OUTDR of the electrode driving devices 3a and 3e
Since the OUT output of the HLO logic is the + PULSE signal, according to the input / output logic of FIG.
High potential HV during H period of LSE signal, low potential LV during L period
And are output to the electrodes 1a and 1e, respectively. Similarly, since the OUT output of the HLO logic is the -PULSE signal, the outputs OUTDR of the electrode driving devices 3b and 3f are first of low potential LV during the L period of the -PULSE signal according to the input / output logic of FIG. During the H period, the high potential HV is output to the electrodes 1b and 1f, respectively.

The output OUTD of another electrode driving device
R is because the HI output of HLO logic is L,
According to the input / output logic of FIG. 11, the output is open, and the electrodes connected to the electrode driving device are open.

As described above, when the output signal OUTDR is output from each electrode driving device to each electrode, the potential of each electrode changes from the electrode of high potential HV toward the electrode of low potential LV.
An ink current flows through the conductive ink filling the space between the electrodes. Then, the direction of this current is changed by switching the electrode potential, and an alternating current is passed through the conductive ink between the nozzles. Then, the conductive ink generates heat due to the alternating current, and bubbles are generated to eject the ink.

FIG. 12 shows + PULSE = H, -PULSE =
The electrode potential when L and the direction of current flow are shown.
A current Ia flows from the electrode 1a to the electrode 1b in the nozzle 2a.
b, a current I is applied to the nozzle 2e from the electrode 1e to the electrode 1f.
ef flows. Furthermore, + PULSE = L, -PULSE
= H, a current Iba flows from the electrode 1b to the electrode 1a in the nozzle 2a and a current Ife flows from the electrode 1f to the electrode 1e in the nozzle 2e as shown in FIG. As described above, the currents Iab and Iba alternately flow through the nozzle 2a, and the currents Ief and Ife alternately flow through the nozzle 2e, and an alternating current is generated to heat and boil the conductive ink, and the ink is ejected from the nozzles 2a and 2e. Is discharged, and the discharge of the first row nozzle group of each block is completed.

Then, the discharge mode of the second row nozzle group is entered. First, the second row nozzles 2b, 2f, 2 for each block
Since the three nozzles j are driven, the time division signals T2 and T3 are output from the CPU 6 as shown in the timing chart of FIG. Since only the nozzle 2b of the second row nozzle is ON, the CPU 6 outputs the data B and data C to the HLO logic at the same timing as when driving the first row nozzle, and outputs all other data to OFF. Has been done.
Then, basically, each HLO logic and each electrode driving device operate similarly to the previous first-row nozzle driving. Therefore,
The output OUTDR of the electrode driving device 3b is as shown in FIG. 11 because the OUT output of the HLO logic is the + PULSE signal.
In accordance with the input / output logic of, the + PULSE signal has a high potential HV during the H period and a low potential LV during the L period and is output to the electrode 1b.

Similarly, the output OUT of the electrode driving device 3c
Since the OUT output of the HLO logic is the −PULSE signal, the DR is first − depending on the input / output logic of FIG.
The PULSE signal has a low potential LV during the L period and a high potential HV during the H period, and is output to the electrode 1c. Further, the output OUTDR of the other electrode driving devices becomes open according to the input / output logic of FIG. 11 because the HI output of the HLO lodge is L, and each electrode connected to the electrode driving device is It is open. Also, the output OUT of the HLO logic 4b when driving the first row nozzle is -P
In contrast to ULSE, the output OUT of the HLO logic 4b when driving the second row nozzles changes to + PULSE. As described above, the alternating current flows through the nozzle 2b, the conductive ink generates heat, bubbles are generated, and ink is ejected.

[0016]

In the conventional ink jet head control device as described above, when the nozzles 2a and 2e eject ink, the adjacent electrodes 1a and 1a forming the nozzle 2a are formed.
When the potential of the electrode 1b is a low potential LV and the potential of the electrode 1e is a high potential HV among the adjacent electrodes 1d and 1b forming the nozzle 2e, the electrode between the electrodes 1b and 1e that are not adjacent to each other is A leak current Ieb flows from 1e toward the electrode 1b, and another non-flying nozzle 2 between the electrode 1b and the electrode 1e.
Leakage current also flows in b, 2c, and 2d. Therefore, the conductive ink generates heat due to this leakage current, and the nozzles 2b, 2c, 2d
In addition, unnecessary ink ejection may occur, and if the leakage current is prevented by controlling the potentials of the electrodes 1b and 1e to be equal, the HLO logic becomes complicated and the circuit cost increases. Had. SUMMARY OF THE INVENTION The present invention solves the above conventional problems, and an object of the present invention is to provide an inkjet head controller having a simple controller and no leakage current.

[0017]

In order to achieve the above object, the present invention comprises an odd number of nozzles in a block and fixes the first pulse potential level at the start of driving to each electrode, The configuration is such that each electrode is driven.

[0018]

According to the present invention, since the first pulse potential for starting the drive to each electrode is fixed for each electrode according to the above configuration, the control device can be simply constructed and the number of nozzles in the block is set to an odd number. Therefore, the potentials of the adjacent electrodes of the nozzles that perform simultaneous ejection become the same potential, and the leakage current is eliminated.

[0019]

An embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of an inkjet head controller according to an embodiment of the present invention, which includes 50a, 50b, 50
c, 50d, 50e, 50f, 50g, and 50h are HLO logics that output data for determining high voltage output, low voltage output, and open output to the electrode driving device. FIG. 2 is a detailed circuit diagram of the HLO logic 50a. Is a selection circuit which outputs the signal + PULSE from the pulse generator 5 to OUT by the signal from the CPU 6 to T1 and T2, and also outputs the high impedance signal HI, and 8 is the print data ON and OF from the CPU 6.
A latch circuit for latching F, 9 is an AND circuit which performs a logical product of the output LAT from the latch circuit 8 and the output SELOUT from the selection circuit 51, and FIG. 3 shows the input / output logical relationship of the HLO logic. It is a logic diagram. The block configuration is such that three nozzles 2a, 2b, 2c are block A, three nozzles 2d, 2e, 2f are block B, one nozzle 2g is block C, and the number of nozzles in the block is an odd number. The row nozzles are three nozzles 2a, 2d, and 2g, the second row nozzle is two nozzles 2b and 2e, and the third row nozzle is two nozzles 2c and 2f. Other configurations are the same as those of the conventional example. Has become.

FIG. 4 is a timing chart showing that the inner nozzles 2a and 2d of the first row nozzles of each block, the inner nozzles 2b of the second row nozzles of each block are ON, and the other nozzle groups are all OFF. 5 drives the first row nozzle of each block, the potential of each electrode when + PULSE = H, -PULSE = L and the current flowing through each electrode at that time, FIG. 6 drives the first row nozzle of each block, + PULSE = L,
The potential diagram showing each electrode potential when -PULSE = H and the current flowing through each electrode at that time is shown.

The operation of the ink jet head controller having the above structure will be described below. First, since the three nozzles of the first row nozzles 2a, 2d, 2g for each block are driven, the time division signals T1, T2 are output from the CPU 6 as shown in the timing chart of FIG. As a result, + PULSE and -PU, which are out of phase with the pulse generator 5, are synchronized with the falling edges of the time division signals T1 and T2.
The LSE signals are simultaneously output for a predetermined number of pulses of 3.

As a result, the + PULSE and -PULSE signals which are out of phase are output to all HLO logics. In addition, since the CPU 6 turns on the first row nozzles 2a and 2d for each block in advance and turns off 2g, print data is output to each HLO logic in synchronization with the rising edges of the time division signals T1 and T2. Here, since the nozzles 2a and 2d are ON, the CPU 6 tells the HLO logic that dataA, dataB, dataD, dataE = ON,
Similarly, the output of all remaining HLO logic is OU.
T = L and HI = L are output. All other data signals are OFF.

The outputs of the HLO logics 50a and 50e are OUT = + PULSE and HI = H according to the input / output logic shown in the timing chart of FIG. 4 and the input / output logic of FIG.

Similarly, the HLO logic 50b and 50d are OUT
= -PULSE and HI = H are output. Similarly,
The output of all remaining HLO logic is OUT = 0, HI
= L is output. Then, the OUT and HI signals output from each HLO logic are output to each electrode driving device.

Output OUTDR of the electrode driving devices 3a and 3e
Since the OUT output of the HLO logic is the + PULSE signal, the + PULSE signal is output according to the input / output logic of FIG.
The SE signal has a high potential HV during the H period and a low potential LV during the L period and is output to the electrodes 1a and 1e, respectively. Similarly, the output OUTDR of the electrode driving devices 3b and 3d is as follows because the OUT output of the HLO logic is the -PULSE signal.
According to the input / output logic of FIG. 11, first, the low potential LV is applied during the L period of the −PULSE signal, and the high potential HV is applied during the H period of the electrode 1.
It is output to b and 1d. The output OUTDR of the other electrode driving devices is open according to the input / output logic in FIG. 11 because the HI output of the HLO logic is L, and the electrodes connected to the electrode driving device are open. It is in a state. As described above, when the output signal OUTDR is output from each electrode driving device to each electrode, the electric potential of each electrode fills the space between the electrodes from the electrode of high potential HV to the electrode of low potential LV. Ink current flows through the ink. Then, the direction of this current is changed by switching the electrode potential, and an alternating current is passed through the conductive ink between the nozzles. Then, the conductive ink generates heat due to the alternating current, and bubbles are generated to eject the ink.

In FIG. 5, + PULSE = H, -PULSE =
The electrode potential when L and the direction of current flow are shown.
In the nozzle 2a, a current Iab from the current 1a toward the electrode 1b,
A current Ied is applied to the nozzle 2d from the electrode 1e toward the electrode 1d.
Flows. Furthermore, + PULSE = L, -PULSE =
When H, as shown in FIG.
A current Iba flows toward a and a current Ide flows from the electrode 1d toward the current 1e through the nozzle 2d. As described above, the currents Iab and Iba alternately flow through the nozzle 2a, and the currents Ied and Ide alternately flow through the nozzle 2d, and an alternating current is generated to heat and boil the conductive ink. Is discharged, and the discharge of the first row nozzle group of each block is completed. Here, paying attention to the potentials of the electrodes 1b and 1d which are not adjacent to each other among the electrodes forming the discharge nozzles 2a and 2d of FIGS. 5 and 6, in the case of FIG. 5, the electrode potentials of the electrodes 1b and 1d are both The potential LV, and in the case of FIG. 6, the electrode potentials of the electrodes 1b and 1d both become the potential HV and become the same potential, and the leak current that has conventionally flowed is in a state of not flowing.

Then, the discharge mode of the second row nozzle group is entered. First, 2 of the second row nozzles 2b and 2e for each block
To drive the nozzles, the time division signals T2 and T3 are output from the CPU 6 as shown in the timing chart of FIG. Since only the nozzle 2b of the second row nozzle is ON, the CPU 6 tells the HLO logic that dataB, dataC = ON at the same timing as when driving the first row nozzle.
All other data are output as OFF. Then, basically, each HL is driven similarly to the previous first row nozzle drive.
O logic and each electrode drive device operate. Therefore, the output OUTDR of the electrode driving device 3b becomes O of HLO logic.
Since the UT output is the -PULSE signal, according to the input / output logic of FIG. 3, first, the L period of the -PULSE signal is the low potential LV and the H period is the high potential HV, which is output to the electrode 1b.

Similarly, the output OUT of the electrode driving device 3c
Since the OUT output of the HLO logic is the + PULSE signal, the DR is initially + in accordance with the input / output logic of FIG.
The high potential HV is output to the electrode 1c during the H period of the PULSE signal, and the low potential LV is output during the L period. The output OUTDR of other electrode driving devices is HI of HLO logic.
Since the output is L, the output is open according to the input / output logic of FIG. 3, and each electrode connected to the electrode driving device is in the open state. Further, the output of the HLO logic 50b when driving the first row nozzles and the output OUT of the HLO logic 50b when driving the second row nozzles
Both become -PULSE and are the same signal,
In the signal OUTDR output from the electrode driving device 3b, the initial pulse potential is fixed to the low potential LV regardless of the nozzle row. As described above, the alternating current flows through the nozzle 2b, the conductive ink generates heat, bubbles are generated, and ink is ejected.

The pulse frequency of the pulse generator this time is 5 MHz. The higher the frequency,
There are few bubbles generated by electrolysis and electrode deterioration is small.
Further, the output OUTDR of the electrode drive device this time has a voltage of 50 V when it is at the high potential HV and a voltage of 0 V when it is at the low potential LV. Further, in this embodiment, the number of nozzles in a block is all odd, but one block having an even number of nozzles in a block may be present.

[0030]

As is clear from the description of the above embodiment,
According to the present invention, the number of nozzles in the block is odd, and each electrode is driven by fixing the first pulse potential level at the start of driving to each electrode. Therefore, the logic circuit configuration is simplified. In addition, among the nozzles that are simultaneously driven for each block, the potential of the electrodes that are not adjacent to each other among the adjacent electrodes that form the nozzle in a certain block and the adjacent electrodes that form the nozzle in another block. Therefore, an excellent ink jet head control device that does not generate unnecessary leakage current in the nozzle between the electrodes that are not adjacent to each other, suppresses ink ejection from the OFF state nozzle, and can perform stable ink flight Can be realized.

[Brief description of drawings]

FIG. 1 is a block diagram of an inkjet head control device according to an embodiment of the present invention.

FIG. 2 is a detailed circuit diagram of an HLO logic in the inkjet head control device according to the embodiment of the present invention.

FIG. 3 is an HLO logic input / output logic diagram in the inkjet head control device of one embodiment of the present invention.

FIG. 4 is a timing chart of the inkjet head control device according to the embodiment of the present invention.

FIG. 5 is an electrode potential diagram when + PULSE = H in the inkjet head controller according to the embodiment of the present invention.

FIG. 6 is an electrode potential diagram when + PULSE = L in the inkjet head controller according to the embodiment of the present invention.

FIG. 7 is a block diagram of a conventional inkjet head controller.

FIG. 8 is a detailed circuit diagram of HLO logic in a conventional inkjet head controller.

FIG. 9 is an input / output logic diagram of HLO logic in a conventional inkjet head controller.

FIG. 10 is a detailed circuit diagram of an electrode driving device in a conventional inkjet head control device.

FIG. 11 is an input / output logic diagram of an electrode driving device in a conventional inkjet head control device.

FIG. 12 is an electrode potential diagram when + PULSE = H in the conventional inkjet head controller.

FIG. 13 is an electrode potential diagram when + PULSE = L in the conventional inkjet head controller.

FIG. 14 is a timing chart of a conventional inkjet head controller.

[Explanation of symbols]

[Outside 2] Pulse generator, 6 ... CPU, 7, 51 ... Selection circuit,
8 ... Latch circuit, 9, 11 ... AND circuit, 10 ... ST
OP circuit, 12 ... High voltage power supply, 13 ... Resistor, 14 ... Transistor, 15 ... Diode, 16 ... Field effect transistor (FET).

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hajime Shiraishi 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (2)

[Claims] 1. An ink jet head control device for energizing a conductive ink and causing the conductive ink to fly through a plurality of nozzle holes by the boiling of the ink due to the energizing current, wherein the ink is sent to each of the nozzle holes. It has a plurality of ink channels provided adjacent to each other and a plurality of common electrodes provided so as to be exposed to both of the adjacent ink channels, one of the adjacent common electrodes has a high potential, and the other has the other. Voltage applying means for applying a voltage so that the voltage becomes low potential, and the plurality of ink flow paths are divided into an odd number of blocks, and the voltage applying means is controlled so that the conductive ink is ejected in time division for each block. An inkjet head control device, comprising: 2. The ink jet head control device according to claim 1, wherein the number of nozzles in one block is an even number among the plurality of blocks of the nozzles.