JPS6121837B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention jets pressurized ink having pressure vibrations at a constant frequency from an ink jet nozzle, and charges the ink particles with a charging electrode at a position where the jetted ink separates into ink particles. The present invention relates to inkjet recording in which ink printing is performed by guiding particles to recording paper or a gutter, and particularly to a charge control method for forming charges on ink particles.

Various types of inkjet recording devices of this type have been proposed (for example, IMB Technical
Disclosure Bulletin, Vol. 16 No. 12 May 1974, Japanese Patent Publication No. 47-43450, Japanese Patent Publication No. 46450-1974, etc.). However, in this type of recording device, if the timing of the generation of ink particles and the application of the charging voltage (pulsed) to the charging electrode are misaligned, the amount of charge on the ink particles will not be as intended, and the printing on the recording paper will not be possible. Dots may be misaligned, causing disturbances in recorded images. Therefore, in the past, for example,
As disclosed in Japanese Patent Application Laid-open No. 43450 and Japanese Patent Application Laid-Open No. 50-60131, the timing of applying the charging voltage to the charging electrode is appropriately determined by searching for the appropriate charging phase of the ink particles. .

However, conventionally, when setting the charging timing, the phase of the search pulse (although it is a charging pulse, it is a short pulse in order to know the appropriate charging timing) is sequentially shifted to search for the charging phase, and the charging detection electrode is used to detect ink particles. Charged and uncharged are detected, the search pulse phase at which the ink droplet is charged is searched, and after this search is completed, the phase of the recording charge pulse (which has a wider pulse width than the search pulse) is determined approximately at the center of the pulse width. Since recording is started by setting the unit so that it matches the searched appropriate charge phase, when multiple ink ejecting nozzles are arranged for simultaneous multi-point recording, one
Charge electrodes and charge detection electrodes must be arranged in a ratio of 1,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000,000. There is a problem in that the number of charge voltage amplifiers and charge detection circuits installed at a ratio of 1 becomes enormous. In the printing record after completing the charging timing setting, 1
Recording charging voltage must be applied to the charging electrodes installed at one rate in each injection nozzle at a charging phase fixed by the charging timing setting, and since each charging phase is different from the others, each charging electrode has one charge voltage. There is a problem in that charge control circuits must be installed in a one-to-one correspondence, resulting in an enormous number of charge control circuits. Furthermore, since the separation phases of the individual heads are different, there is a problem in that synchronization with printing data is difficult.

For example, as shown in FIG. 1a, 60 ink jet heads 1 ₁ , 1 ₂ , 1 ₃ , 2 ₁ , 2 ₂ , 2
₃ , 3 ₁ , ... 20 ₃ are arranged and from their ink jet nozzles, pressurized ink that has been given pressure vibrations at a constant frequency by excitation of an electrostrictive vibrator at a constant frequency is jetted, and each charged electrode 41 ₁ ,41 ₂ ,41 ₃ ,
In inkjet recording in which ink particles are charged with 42 ₁ , 42 ₂ , 42 ₃ , ...60 ₃ and the charged ink particles are deflected horizontally with X-axis deflection electrodes XDE (60 sets), each inkjet head 60 charged electrodes 41 in one-to-one correspondence
₁ to 60 ₃ and charge detection electrodes 21 ₁ , 21 ₂ ,
21 ₃ , 22 ₁ , 22 ₂ , 22 ₃ , 23 ₁ , ...
40 ₃ must be placed. In addition, 1st a
In the figure, the first Y-axis deflection electrode YDE1 is
which deflects the charged ink particles upward and forces them into a trajectory where they are not captured by the gutter GA;
The second Y-axis deflection electrode YDE2 forces the charged ink particles deflected by the first Y-axis deflection electrode YDE1 to collide perpendicularly with the surface of the recording paper PR.

FIG. 1b shows a sectional view taken along the line BB in FIG. 1a. first and second Y-axis deflection electrodes YDE1,
A constant deflection voltage is applied to each YDE2. Uncharged ink particles are not affected by the deflection electric field YDE1 and are captured by the gutter GA, but charged ink particles jump over the gutter GA and collide with the recording paper PR. A deflection electric field of a fixed level is applied to each set of X-axis deflection electrodes XDE, and a charging voltage whose peak value changes stepwise and repeats periodically is applied to each charging electrode 41 ₁ to 60 ₃ . is applied, which causes the charged ink particles to be horizontally deflected in steps. The arrangement pitch of the heads ₁₁ to ₂₀₃ (that is, the arrangement pitch of the nozzles) is, for example, 5 mm, and when recording is performed at a density of 8 dots/mm in the horizontal direction, charged ink particles ( (plural) are X-axis deflection electrodes
It is deflected horizontally in 5×8=40 steps by XDE. As a result, recording is performed at a pixel density of 8 dots/mm over a width of 5×60=300 mm in the horizontal direction. When doing this, the charging electrode 41
₁ to ₆₀₃ are 60 pieces, and 60 sets of charge control circuits are required. Moreover, charge detection electrodes 21 ₁ to 40 ₃
The arrangement pitch of the charging electrodes 41 ₁ to 60 ₃ is also 5 mm, and the space for shielding between each electrode is extremely small, preventing interference between the charging detection electrodes 21 ₁ to 40 ₃ that detect minute charges. It is difficult to create a shield to prevent noise and block noise. In addition, it is difficult to shield the lead wires of the charge detection electrodes. However, as long as charging control for recording is performed by searching for an appropriate charging phase for each ink ejecting nozzle, setting the charging phase, and applying a charging voltage at each charging phase to each ink ejecting nozzle as in the past, Various problems cannot be avoided.

SUMMARY OF THE INVENTION An object of the present invention is to provide an inkjet recording method in which the number n of charges is lower than the number m of ink jet nozzles.

In the present invention that achieves the above object, m/n ink jet nozzles (m/n)≧2 are each
ejecting m/n sets of pressurized ink having pressure vibrations of the same frequency but different ink droplet separation phases from ink ejecting nozzles of the same set;
Each one of the n charging electrodes arranged to charge the ejected ink of one set of ink ejecting nozzles has a phase difference between each of the separated phases for charging the ink particles. m/n sets of recording charging voltage pulses are applied. Expressing this in a simplified manner, if three ink jet nozzles are one set, from this one set of ink jet nozzles,
Three sets of pressurized ink having the same frequency of pressure vibration but different ink droplet separation phases are ejected; one ink ejecting nozzle is arranged to charge the ejected ink of one set (three) of ink ejecting nozzles. Three sets of recording charging voltage pulses having phases that charge the ink droplets in each of the separated phases and having mutually different phases are applied to the charging electrode.

According to this, the number n of charging electrodes is n/m compared to the conventional one.
(1/3 in the above example), and the number of recording charge voltage generators can be similarly reduced to n/m. For example, the first, second, and third nozzles are set as one set, and the first, second, and third sets of recording charging voltage pulses are assigned to them, respectively, and the first to third sets of recording charging voltages are applied to one charging electrode. A voltage pulse is applied, but the ink separation phases of these nozzles are different from each other, and the
Since the first to third sets of recording charging voltage pulses are in a corresponding relationship that gives appropriate charging to each nozzle, for example, ink particles ejected from the first nozzle are not charged by the second and third recording charging voltage pulses, but each set of recording charging voltage pulses is Each ink droplet ejected from the nozzle will have only the intended charge. That is, the number of charged electrodes is reduced, but the required recording is still performed.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 2a shows ink jet heads 1 ₁ , 1 ₂ , 1 for implementing the invention in a preferred embodiment.
₃ , 2 ₁ , 2 ₂ , 2 ₃ , 3 ₁ , 3 ₂ , 3 ₃ , ...
20 ₃ shows the arrangement of the charge detection electrodes 21 to 40 and the charging electrodes 41 to 60, and FIGS. 2b and 2c respectively show a sectional view along the line B-B and a sectional view along the line C-C in FIG. 2a. .

The charge detection electrode 21 is a conductor block 2 having ink particle passage holes 21a ₁ to 21a ₃ opened at a pitch equal to the arrangement pitch (5 mm) of the ink jet nozzles.
An insulating coating 21c is applied to 1b, and this insulating coating 2
The surface of 1c is coated with a conductor layer 21d for shielding. Other charge detection electrodes 22 to 40
have a similar structure, and these charge detection electrodes 2
1 to 40 are joined to the back surface of the insulating plate 61. The charging electrode 41 has ink particle passage holes 4 opened at a pitch equal to the arrangement pitch of the ink jet nozzles.
A conductor block 41b having 1a ₁ to 41a ₃ is coated with an insulating coating 41c. The other charging electrodes 42 to 60 have a similar structure, and these charging electrodes 41 to 60 are joined to the surface of the insulating plate 61. Note that the charging electrodes 41 to 60 may also have the same structure as the charging detection electrode 21.

FIG. 3a shows the configuration of a charging timing setting device for implementing the present invention in a preferred embodiment,
The configuration of one block of the excitation phase selection circuit OPS shown therein is shown in FIG. 3b, and the input and output timings of each part of the circuit shown in FIG. 3a are shown in FIG. 3c.

In FIG. 3a, 62 shown at the lower left of the figure is a control circuit, and this control circuit 62 includes an input/output port 62a, a read-only memory (hereinafter referred to as ROM) 62b, a read/write memory (hereinafter referred to as RAM) 62c, and The microcomputer system includes a central processing unit 62d, and the ROM 62b stores program data for setting charging timing and recording control program data, which will be described in detail later. Timing synchronization of the entire circuit is achieved using a 1.8MHz pulse A from a clock pulse oscillator 63.
It is taken on the basis of The clock pulse A is supplied to the input/output port 62a of the control circuit 62 and the 9-ary counter 6.
4 and hexadecimal counter 65.

A 9-ary counter 64 counts the clock pulses and provides a count code to a first decoder 67. Output signals of output terminals 0 to 8 of decoder 67
One of _B0 to _B8 , _B0 , is applied to a JK type flip-flop ₆₈₁ , and the Q output of this flip-flop ₆₈₁ is an 8-bit parallel output,
It is applied to a serial shift type shift register ₆₈₂ . The parallel outputs F ₁ to _{F 8} of the shift register ₆₈₂ and _{the output F 0 of} the shift register 681 are pulses obtained by dividing the clock pulse A by 1/18, as shown in FIG. 3c _{. 8} has a phase shift of the clock pulse A by a pulse period of _2Tc . Note that these pulses F ₀ ~
F ₈ is converted into a sine wave with one pulse period of one cycle, and one of them is selected as the excitation reference wave for the electrostrictive vibrator of the inkjet head, and F ₀ to F ₈ are sequentially selected. The excitation phase, that is, the ink pressure oscillation phase, is shifted by selecting . These pulses F ₀ ~ F ₈
is constantly applied to the excitation phase selection circuits OPS (60 from No. 1 to No. 60).

Each unit circuit of the excitation phase selection circuit OPS consists of nine JK flip-flops F1, as shown in Figure 3b.
~F9, nine AND gates A1 to A9, and 1
By sequentially setting the flip-flops F1 to F9 one by one, the AND gates A1 to A9 are turned on one by one, and the flip-flops ₆₈₁
and the output pulse F ₀ ~ of shift register ₆₈₂
F ₈ sequentially passes one set of AND gates A1 to A9
The signal is output from the OR gate R1 and applied to the sine wave converter SIN. By locking one flip-flop (eg F3) in the set state, only one set of pulses _F2 is output. In this way, the excitation phase selection circuit OPS selectively outputs the excitation reference pulses F ₀ to F ₈ (that is, excitation phase shift), and also latches to output only the excitation reference pulse of the desired phase (excitation phase shift). (fixed) function. Excitation phase selection circuit OPS
The output of each unit circuit (Fig. 3b) is applied to each unit circuit of the sine wave converter SIN (60 sets), where it is converted into a sine wave with a constant peak value, and the output is applied to each unit circuit of the sine wave converter SIN (60 sets). 69 ₁ ~ 69
applied to each of _{the 60} . Excitation voltage amplifier 69
The respective outputs ₁ to ₆₉₆₀ are applied to the electrostrictive vibrators of the ink jet heads ₁₁ to ₂₀₃ , respectively.

The hexadecimal counter 65 is connected to the clock pulse oscillator 6.
3 output pulses are counted and the second decoder 7
Get to 0. The decoder 70 outputs a pulse C 0 to its output terminal 0 when the count value is 0 and 1, outputs a pulse C ₁ to its output terminal 1 when the count value is 2 and 3, and outputs a pulse C ₁ to its output terminal 1 when the count value is 5. and 6, the pulse C ₂ is output to the output terminal 2, and so on, the third c is output to the output terminals 0 to 8, respectively.
The settings are such that pulses C ₀ to C ₈ are output at the timing shown in the figure. Output terminals 1 and 4 of decoder 70
and 7 output pulses are output from the first group of ink jet heads 1 ₁ , 2 ₁ , 3 ₁ , 4 _{1 ,} .
Inkjet head 1 ₂ , 2 of the second group
₂ , 3 ₂ , ... 20 ₂ and the third group of ink jet heads 1 ₃ , 2 ₃ , 3 ₃ , ... 20 ₃
The search charging pulses _D0 to _D2 are applied to the AND gates A10 to A12 to perform search charging on the ink ejected from the ink jetting nozzles. The AND gate A10 is turned on by the control circuit 62 when searching for the ink droplet separation phase of the ink ejected from the first group of ink jet heads 1 ₁ , 2 ₁ , 3 ₁ , . . . 20 ₁ . A1
1 is the inkjet head 1 ₂ of the second group,
2 ₂ , 3 ₂ , . . . 20 ₂ , the AND gate A 12 is turned on by the control circuit 62 when searching for the ink droplet separation phase of the ink jet heads 1 ₃ , 2 ₃ , 3 of the third group. ₃ ,...
. . 20 ₃ is turned on by the control circuit 62 when searching for the ink droplet separation phase of the ejected ink. The output pulses of AND gates A10 to A11 are passed through OR gate _R2 to switching circuit 71 (first
It is applied to one input terminal of each unit circuit (consisting of unit circuits numbered 20 to 20). Each unit circuit of the switching circuit 71 is switched to a mode in which the output of the OR gate R2 is applied to the charging electrodes 41 to 60 by a search command signal from the control circuit 62 during the ink droplet separation phase search. When no signal is being emitted, the voltage amplifiers 72 ₁ to 7
The mode is such that an output of 2 ₂₀ is applied to the charging electrodes 41-60.

The outputs C ₀ -C ₂ of the output terminals 0 - 2 of the decoder 70 are applied to the input terminals of the first group of AND gates A13 ₁ , A14 _{1 ,} . output of
C ₃ to C ₅ pass through the or gate R4 to the second group of AND gates A13 ₂ , A14 ₂ , ...A32
₂ , and the outputs C ₆ to C 8 of the output terminals 6 to ₈ of the decoder 70 are applied to the third group of AND gates A13 ₃ and A14 through the OR gate R5.
₃ , . . . A32 is applied to one input terminal of ₃ . As shown in FIG. 3c, the outputs E ₀ to E ₂ of the OR gates R 3 to R 5 have a pulse width three times that of the charge search pulses D ₀ to _{D 2} at the center, and are used as charge pulses during recording. It will be done.

As shown in Figure 2a, heads ₁₁ to ₁₃ are the first
The m=60 heads are divided into n=3 groups, such that the head sections face one charging electrode, and the heads ₂₁ to ₂₃ face one charging electrode 42 as a second head section. One head section is composed of n = 3 heads that are adjacent to each other, and m/n = 20 head sections are constructed, with one head section for each head section.
Charge electrodes and charge detection electrodes are installed, and correspondingly, AND gates A13 ₁ to A
32 ₃ is also A13 ₁ ~A13 ₃ , A14 ₁ ~A1
4, . . . A32 ₁ to A32 ₃ are each divided into 20 sections.

One line of print data (40 x 60 = 2400 bits) is serially input to the shift register 73 under the control of the control circuit 62 (in order to increase the input speed, 2400 bits are input in parallel). ), the shift register 73 outputs 60 bits at the same time every 40 bits, that is, 60 parallel output terminals are formed, with one output terminal for every 40 serial bits. , each output terminal is sequentially connected to AND gates A13 ₁ , A13 ₂ ,
It is connected to A13 ₃ , A14 ₁ , . . . A32 ₃ . During recording, the shift register 73 inputs every 60 bits of the 2400-bit printing data for one line into each AND gate _A131 to _{A323 in} parallel, and during recording of one line, the AND gates _A131 to _A323 40 bits of printing data are serially applied to each line, and during this time, AND gates _A331 to _A3320 are all turned on by the output of the control circuit 62, so that each line of 40 bits of printing data is Voltage amplifier 72 ₁
~72 Input serially to ₂₀ .

First and second data selectors 74 and 75 are provided to shift and fix the excitation phase of each ink jet head _11-203 for ink droplet separation phase retrieval and setting _.
The first data selector 74 has an input terminal connected to nine output lines of the input/output port of the control circuit 62, and 60 sets of output terminals, each set of nine lines. The output line of the excitation phase selection circuit OPS
(See Figure 3b). The data selector 74 has 60 switching control input terminals from 0 to 59, and when the input voltage at input terminal 0 is at a high level "1", that input (nine terminals) is selected as the first input terminal of the selection circuit OPS. When the input voltage at input terminal 1 is "1", the input is connected to the second unit circuit of OPS, and the input voltage at input terminal 59 is "1". Sometimes, a switching connection operation is performed in which the input is connected to the 60th unit circuit of the OPS. The second data selector 75 also performs the same operation as the first data selector 74, but its output line is used to reset the JK flip-flops F1 to F9 (Figure 3b).
books, so the output is 60 books. A switching control signal is applied from a decoder 76 to switching control input terminals 0 to 59 of the first and second data selectors 74 and 75. A count code of a sexagesimal counter 77 is given to the decoder 76, and a count pulse is given to the sexagesimal counter 77 from the timing circuit 62. If the count code of the counter 77 now represents zero, the output terminal 0 of the decoder 76 is at a high level "1", so that the data selectors 74 and 75 select the first unit circuit of the selection circuit OPS and the control circuit. 62 is connected. When the control circuit 62 gives one pulse to the counter 77, the data selectors 74 and 75 select the second OPS.
When the No. 3 unit circuit is switched and connected to the control circuit 62, and one more pulse is given to the counter 77, the data selectors 74 and 75 switch and connect the No. 3 unit circuit of the OPS to the control circuit 62, and so on. Each time the counter 77 counts up, each unit circuit of the selection circuit OPS is sequentially switched and connected to the timing circuit 62.

Each output terminal of the charge detection electrodes 21 to 40 is connected to an analog switching circuit 78 (20 connected to one output terminal).
The analog switching circuit 78 is connected to the input terminal of each switching element (20 pieces) of
It has two switching control input terminals. The output end of the switching circuit 78 is connected to the input end of an amplifier 79 that amplifies and binarizes the charge detection signal, and the output end of the amplifier 79 is connected to the input line of the input/output port 62a of the timing circuit 62. There is. The operation of the analog switching circuit 78 is similar to that of the first and second data selectors 74 and 75, and each time the timing circuit 62 gives one pulse to the counter 80, the output of the decoder 81 is switched, and in response to this, the output of the decoder 81 is switched. Then, one of the charge detection electrodes 21 to 40 is selectively connected to the amplifier 79 in sequence.

The 40-decimal counter 66 is the binary counter 68 ₁ of 1
Count the output pulses _F0 and convert the count code to a digital-to-analog converter (hereinafter referred to as D/A).
converter) 82. The output of the D/A converter 82 thus outputs an analog voltage that increases stepwise by 40 steps, returns to the base level, and then increases stepwise again. This analog voltage is amplified by voltage amplifier 83 to a level that deflects the charged ink droplets horizontally by 40 steps.
20 switching type amplifiers 72 ₁ to 7
2 Applied to ₂₀ . Each amplifier 72 ₁ to 72 ₂₀ is
AND gates A33 ₁ to A3 given to them
3 When the output of ₂₀ is high level “1”, the amplifier 83
A voltage obtained by amplifying the output of is applied to the switching circuit 71.
When the count value of the 40-decimal counter 66 reaches 40, the NAND gate 84 detects this and provides a signal of "1" to the control circuit 62. The control circuit 62 reads the printing data, reads and records it, and performs the AND gate A33 based on the pulse representing the count period.
₁ to A33 ₂₀ on control timings are taken.

Next, the operation of the circuit shown in FIG. 3a will be explained.
Now, when a signal representing the ink particle separation phase search and setting arrives at the input/output port 62a, the control circuit 6
In step 2, the ink droplet separation phase search and setting program data is read from the ROM 62b, and based on this program data, the separation phase of the ink jetted by each ink jet head ₁₁ to ₂₀₃ into ink particles is searched and set. is started. In this case, first the counters 64 to 66, 7
7 and 80 are cleared by the output of the control circuit 62, and a search command signal is given to all of the switching circuits 71 (1-20).

Clock pulses generated since this clear
In response to A ₁ , A ₂ , A ₃ , ..., the signals A,
_B0 ~ _B8 , _C0 ~ _C8 , _D0 ~ _D2 , _E0 ~ _E2 , and _F0 ~
_F8 has the timing shown in FIG. 3c. By this clearing, the count codes of counters 77 and 80 are expressed as 0, so decoders 76 and 8
1 outputs "1" to output terminal 0,
Therefore, the data selectors 74 and 75 select the output line of the control circuit 62 from the excitation phase selection circuit OPS.
The analog switching circuit 78 connects the charge detection electrode 21 to the first unit circuit of the amplifier 79.
Connect to. In this state, the control circuit 62 turns on the AND gate A10, applies a charge search pulse D ₀ to the charge electrode 41, and monitors the charge detection signal of the charge detection electrode 21.

(a) If it is uncharged, a reset pulse is sent to the line connected to the data selector 75 to reset the flip-flop F of the first unit circuit.
1 to F9 are all reset, and then the first of the nine signal lines connected to the data selector 74 is set to high level "1" to set the flip-flop F1. As a result, the excitation pulse F ₀ of the first phase is applied to the first sine wave converter SIN through the AND gate A1 (FIG. 3b). Then, the control circuit 62 monitors the charge detection signal and if it is still uncharged, the control circuit 62 sends a reset pulse to the data selector 75 to reset the OPS.
reset the flip-flops F1 to F9 of
Subsequently, the second of the nine signal lines connected to the data selector 74 is set to "1" to set the flip-flop F2. As a result, the second phase excitation pulse F ₁ is passed through the AND gate A2.
is applied to the first sine wave converter SIN. The control circuit 62 then monitors the charge detection signal. The control circuit 62 controls OPS (3b) until the charge detection signal indicates "charge".
Set the flip-flops F1 to F9 in the figure) in sequence, and set the first one of the sine wave converter SIN.
Switch and apply F ₀ to F ₈ in sequence. In other words, the first
The excitation voltage phase of the first group of ink jet heads ₁₁ of the section is sequentially shifted.
The excitation voltage of any one of these F ₀ to _{F 8} , that is, any phase during the shift, is applied to the head 1.
₁ , the ink droplet separation phase of head ₁₁ matches the charging pulse of _D0 , and the ink droplets are charged. By stopping the phase shift when this charge is detected, the ink droplet separation phase setting of the head ₁₁ is completed.

(b) At the beginning of (a) above, if it is "charged" from the beginning, head 1 of the first section
Any of the ink particles formed by _{heads 1} , ₁₂ , and ₁₃ will be charged by the charging pulse _D0 , and it may not be possible to immediately determine that the ink particles ejected from heads 1 _{to 1} are charged. sell. Therefore, in this case, the control circuit 62 first applies one pulse to the counter 77 to connect the control circuit 62 to the second unit circuit of the selection circuit OPS, and performs the process described in (a) above.
The phase of the excitation voltage applied to the head ₁₂ is sequentially shifted in the same way as the phase shift in , and it is observed whether or not it changes from "charged" to "uncharged".
When the state changes to "uncharged", the counter 77
was counted up to the code specifying OPS No. 1, and the control circuit 62 was connected to OPS No. 1 again to perform the phase shift and setting described in (a) above, and the state did not change to "uncharged". In this case, one pulse is further applied to the counter 77 (in this case, the count value is 2), the control circuit 62 is connected to the third unit circuit of the selection circuit OPS, and the head 1 is
₃ , sequentially shift the phase of the excitation voltage applied to
When the state changes from "charged" to "uncharged",
The counter 77 is made to count up to the code that specifies the first OPS, and the control circuit 62 is turned on again.
If you connect it to OPS No. 1 and perform the phase shift and setting described in (a) above, but the state does not change to "uncharged", the current excitation voltage phase of Dod ₁₁ will eventually become charged pulse D ₀ This means that the ink droplet separation phase search and settings for the head ₁₁ are completed.

The above steps (a) and (b) complete the setting of the ink droplet separation timing for the first group of ink jet heads ₁₁ of the first section.

Next, the control circuit 62 turns off the AND gate A10, turns on A11, applies a charging pulse _D1 to the charging electrode 41, and sets the counter 77 to the second OPS.
Charge detection electrode 21 with a count value of 1 representing the number
The output of the head 12 is monitored, and if the output is "uncharged", the phase of the excitation voltage applied to the head ₁₂ is sequentially shifted in the same manner as in (a) above. If it is "charged", the excitation phase setting of head 1 ₁ has already been set.
D ₀ has ended, and in this phase the charging pulse D ₁ cannot charge the ink droplets ejected from head 1 ₁ , so it means that the ink droplets ejected from heads 1 ₂ or 1 ₃ are charged. , the control circuit 62 first applies one pulse to the counter 77 to set the count value to 2. The control circuit 62 is connected to the third unit circuit of the OPS, and the phase of the excitation voltage applied to the heads ₁₃ is sequentially shifted. Check whether it changes from "charged" to "uncharged". When the state changes to "uncharged", the counter 77 is returned to the count value 1, and the phase shift of the excitation voltage of the head ₁₂ is performed in the same manner as in (a) above. If the head ₁₂ remains "uncharged", no phase shift is necessary since the current ink drop separation phase of the head 12 matches the charging pulse _D1 .

With the above steps, the setting of the ink droplet separation timing for the second group of ink jet heads ₁₂ of the first section is completed.

Next, the control circuit 62 turns off the AND gate A11, turns on the AND gate A12, applies a charging pulse _D2 to the charging electrode 41, and controls the counter 77.
is set to a count value of 2, which represents the third OPS, and the output of the charge detection electrode 21 is monitored. If the output is uncharged, the head ₁₃ is set in the same manner as in (a) above.
Shift the phase of the excitation voltage applied to the
If it is "charged", the excitation phase settings D ₀ and D ₁ of the heads ₁₁ and ₁₂ have already been completed, and in these phases, the charging pulse D ₂ causes the injection of the heads ₁₁ and ₁₂ . Since the ink droplets cannot be charged, the control circuit 62 does not phase shift the ink droplet separation of the head ₁₃ because the ejected ink droplets of the head ₁₃ are charged by the charging pulse _D2 . As a result, the setting of the ink droplet separation timing for the third group of heads ₁₃ of the first section is completed, and the setting of the excitation voltage phase for the heads ₁₁ to ₁₃ of the first section is completed.

The control circuit 62 then applies one pulse to the counter 80 to set the count value of the counter 80 to 1, and switches the analog switch 78 to the charge detection electrode 22.
The mode is switched to connect the output terminal of the amplifier 79 to the input terminal of the amplifier 79, and the head 1 of the first section described above is connected.
Similarly to the excitation voltage phase search and setting for heads _{21 , 22} , and ₂₃ of the first, _{second, and} third groups of the second section, Similarly, the third
Heads from section to 20th section 3 ₁
~20 ₃ Excitation voltage phase search and settings,
When this is completed, the recording control program is read from the ROM 62b, and based on this program, the timing display signal is set to a high level "1" indicating "recordable (printed data accepted)", and the printed data acceptance timing pulse is printed. The data is given to the photo data transmitting side (not shown). In addition, all unit circuits 1 to 20 of the switching circuit 71 are connected to amplifiers 72 ₁ to 72 ₂₀
switch to the side.

When the printing data is sent, the control circuit 62,
After storing one line of printing data in the shift register 73 by counting timing pulses during that time or by receiving line-coordinated pulses from the transmitting side, the control circuit 62 sets the shift register 73 to readout. After that, a short pulse synchronized with one output pulse _F0 of the binary counter ₆₈₁ is given to the shift register 73 as a shift clock using the output pulse of the NAND gate 84 as a starting point, and the AND gates _A331 to A
₃₃₂ is turned on until the next output pulse arrives from the NAND gate 84. As a result, 40-bit printing data is serially output to each of the AND gates _A131 to _A323 . AND gates of the first group A13 ₁ , A14 ₁ , ...
A32 ₁ receives a charging pulse from OR gate R3.
A recording charge pulse E ₀ synchronized with D ₀ is applied to the second group of AND gates A13 ₂ , A14 ₂ , . . . A3
2 ₂ receives the recording charge pulse E ₁ synchronized with the charge pulse D ₁ from the OR gate R4, and also the AND gates A13 ₃ , A14 ₃ , . . . A32 of the third group.
_Since the recording charging pulse E 2 synchronized with the charging pulse D ₂ is applied to the recording pulse E ₂ from the OR gate R 5 to the
Section and gate A13 ₁ , A13 ₂ ,
When the print data applied to _A133 is at a high level "1" representing "record", the output of AND gate _A331 is output to heads ₁₁ , ₁₂ , ₁₃ as shown in _G1 in FIG. When all of the ejected ink particles are charged with a long pulse width, and low-level printing data of "0" representing "non-recording" is applied only to the AND gate A13 of the first group, as shown in _G2 . , the output of the AND gate _A331 is a short pulse width such that the ejected ink droplets of the head ₁₁ are not charged. In this way, recording charge pulses E ₀ to _{E 2} charge three heads 1 ₁ and 1, respectively.
Since the timing for charging the ejected ink particles _{2 and 1 3} is determined, _the printing data is The ejected ink droplets from each head can be selectively charged depending on the ink droplets.

The operations and operation sequences of ink droplet separation phase search, setting, and recording explained above are as follows:
All of this is done based on the program stored in the ROM 62b of the control circuit 62.

As described above, according to the present invention, the intended purpose is achieved. Note that in the above description, only a specific device configuration and a specific embodiment have been described, but the present invention is not limited thereto. For example, the number m of heads and the number n of one group need not be limited to m=60 and n=3. According to the inventor's study, currently 2≦
It is more practical that n≦4.

In addition, although the excitation voltage phase shift of the electrostrictive vibrator was illustrated as a mode of separation phase control of ink particles,
The separation phase of the ink particles can also be changed depending on the excitation voltage level of the electrostrictive vibrator. Therefore, instead of excitation voltage phase control, the separation phase of ink particles may be searched and set by excitation voltage level control.

[Brief explanation of the drawing]

FIG. 1a is a perspective view showing the configuration of one conventional inkjet recording device, and FIG. 1b is a B-
It is a sectional view taken along the B line. FIG. 2a is a perspective view showing the main structural parts of an inkjet recording apparatus embodying the present invention, and FIGS. 2b and 2c are cross-sectional views taken along lines B--B and C--C, respectively.
FIG. 3a is a block diagram showing an operation control circuit of an inkjet recording apparatus embodying the present invention, FIG. 3b is a block diagram showing a part of the configuration in detail, and FIG.
FIG. 3C and FIG. 4 are time charts showing the input/output signal timing of each part of the circuit shown in FIG. 3A. 1 ₁ - 20 ₃ : Ink jet head, 21 -
40: Charged detection electrode, 41-60: Charged electrode, 6
1: Insulating plate, 62: Control circuit, OPS: Excitation phase selection circuit, SIN: Sine wave converter.

Claims (1)

[Claims] 1. Pressurized ink having a constant frequency of pressure vibration is ejected from an ink ejection nozzle, the ink particles are charged with a charging electrode at a position where the ejected ink separates into ink particles, and the charged ink particles are deflected by an electric field. In inkjet recording, which records on the recording surface by deflecting the inkjet at ejects m/n sets of pressurized ink having different ink droplet separation phases; one each of n charging electrodes arranged to charge the ejected ink of one set of ink ejection nozzles; An inkjet recording method characterized in that m/n sets of recording charging voltage pulses are applied that charge the ink droplets in each of the separated phases and have a mutual phase difference.