JPS6356456A - Multinozzle ink jet recorder - Google Patents

Abstract

PURPOSE:To simplify hardware and reduce device cost by providing only one set of charge voltage generators which periodically generate a charge voltage which corresponds to a printing position which is changed over in cyclic units of the pressure vibration of liquid ink supplied to a nozzle. CONSTITUTION:Only one set of charge voltage generation circuits which generate charge voltage which corresponds to a Y direction printing position stepwise from an address counter 401 to resistors R1, R1 are provided in a charge voltage generator 40(40a+40b). When the first switching circuit which consists of an FET 4031, an arithmetic amplifier OPA5 and an output transistor Tr1, the second switching circuit which consists of an FET 403, an arithmetic amplifier OPA52 and an output transistor Tr2 and the third switching circuit which consists of an FET 403, an arithmetic amplifier OPA53 and an output transistor Tr3 transmit an image signal which indicates a record, charge voltage is applied to charge electrodes 91, 92 and 93. Only the set of charge voltage generation circuits suffice, so that the configuration of an ink jet recorder becomes simple and less costly.

Description

Detailed Description of the Invention [Technical Field] The present invention jets vibrated ink from a nozzle, selectively charges the jetted ink at a position where it separates into ink particles using a charging electrode, and transforms the charged ink particles into The present invention relates to an inkjet recording device in which the deflection is caused by a deflection electrode to collide with a predetermined position on recording paper, and particularly relates to the application of a charging voltage to each charging electrode in an inkjet recording device using a plurality of nozzles.

(2) Prior Art In this type of inkjet recording, ink continuously ejected from a nozzle is separated into ink particles of a predetermined size while in flight, so-called particleization. This particle formation is performed by applying regular high-frequency vibrations to the pressurized ink in the ink jet head. A plate-shaped or cylindrical electrostrictive vibrator is generally used as a means for applying vibration. . When each ink particle is selectively charged with a predetermined charge according to recorded data, and the ink particles are passed through a predetermined deflection electric field, the ink particles are charged depending on the presence or absence of charge or the level of charge. The flight trajectory is deflected, and each ink droplet collides with a predetermined position on the print medium or with an ink receiver (gutter) for collection depending on print data, thereby performing predetermined printing. The principle of charging in inkjet recording is based on the fact that the ink is broken at predetermined intervals while the ink tip is charged by electrostatic induction in the electric field generated by the charging electrode, leaving a charge in the separated ink. .

In color recording or single-color divided recording for increasing the recording speed of one sheet, a plurality of nozzles are provided, and accordingly, the number of charging electrodes and charging voltage generators equal to the number of nozzles is provided.

In this type of inkjet recording, it is necessary to apply a charging voltage at the time when the ink jetted through the nozzle separates into particles, so the configuration of the charging voltage generator is quite complex. Providing such voltage generators for the number of nozzles means that
There are significant disadvantages in terms of hardware and equipment costs.

■Purpose The present invention simplifies hardware by combining a set of charging voltage generators that periodically generate charging voltages corresponding to the printing position, which are switched in units of cycles of pressure vibration of the ink liquid supplied to the nozzles. The purpose is to reduce equipment costs.

■Structure In order to achieve the above object, the present invention includes a plurality of nozzles; an ink supply means for supplying pressurized ink having pressure vibration to each nozzle; each selectively charging the ink ejected from each nozzle; , a plurality of charged electrodes; a deflection electrode that deflects charged ink particles; and a gutter that captures non-deflected ink particles. a set of charging voltage generating means that periodically generates a charging voltage of switch means;

According to this, a set of charges' generated by the charging voltage generating means
The i'Ii voltage is distributed to each nozzle by a plurality of switch means. Therefore, the number of charging voltage generating means that periodically generates the charging voltage corresponding to the printing position is only one set.
Accordingly, the hardware becomes simpler and the device cost is reduced.

For example, in an embodiment in which ink of different colors is ejected from three nozzles, each of the plurality of switch means may be turned on/off in accordance with the image signal for color assignment. For example 3
In an embodiment in which monochrome divided recording is performed using individual nozzles, each of the switch means may be turned on/off in accordance with the image signal assigned to the nozzle.

Setting the charging voltage phase relative to the ink separation phase, or the ink separation phase relative to the charging voltage phase, for synchronization of applying a charge '1' voltage to the charging electrode when the ink ejected from the nozzle separates into particles. The phase search that performs
This is a fairly complex control logic and is relatively time consuming. Therefore, in a preferred embodiment of the present invention, in a monochrome recording mode, a plurality of nozzles communicate with one ink chamber, and the pressure vibration phase of the pressurized ink supplied to the ink chamber is adjusted to the charging voltage phase. Perform a phase search to set the According to this, only one set of circuits is required for performing this phase search. Note that even if the number of phase search circuits is the same as the number of nozzles, only one set of charging voltage generators is required by adopting a mode in which phase search is performed to adjust the pressure vibration phase with respect to the charging voltage phase.

Other objects and features of the present invention will become apparent from the following description of embodiments with reference to the drawings.

〔Example〕

FIG. 1 shows the main mechanical parts of an inkjet printer embodying the present invention in one embodiment, and FIG. 2 shows a side view thereof. In these drawings, two guide bars 171e17 are parallel to the axis 16 of the platen 15 on which the recording paper 14 is mounted.
2 are arranged, and these guide bars 171, 17
2, a carriage 18 is mounted so as to be able to reciprocate along them. The carriage 18 is driven by a main scanning drive system (not shown) via a wire 19 fixed to it.
It is driven to the right from the illustrated home position, reversed at a position outside the paper width on the right, and driven to the left.

A head assembly support base 20 is pivotally attached to the carriage 18, and an adjustment mechanism (not shown) allows the carriage 1
The rotational position can be adjusted A1 along the top surface of 8. A helad base 21 is attached to the head assembly support base 10.
is pivotally mounted, and the rotational position can be adjusted A2 along the vertical plane of the base 20 by an adjustment mechanism (not shown). An ink ejecting head 1 having a cylindrical electrostrictive vibrator fixed to a metal pipe is fixed to the head base 21 . A nozzle plate having three nozzles is fixed to the tip of the metal pipe.

The head assembly support base includes a charged electrode plate 2. shield i
! Pole plate 3. A deflection electrode 41 and a shield electrode plate 6 are fixed to the carriage 18, and a conductive gutter GR for capturing non-imprinted ink particles is fixed to the carriage 18.

The end surface of the shield electrode unit 6 facing the recording paper 14 is a curved surface centered on the axis of the platen shaft 16, as shown in FIG. 2, so that each part of the end surface is equidistant from the recording paper surface. It has become.

A charge detection electrode unit 22 is fixedly disposed in front of the ink particles that are ejected when the carriage 18 is at the home position and are removed from the gutter. unit 2
An opening is formed in the front wall of 2, and a charge detection voltage tu13 and a shielding plate 5 are installed inside this opening.

The charge detection electrode 13 is fixed with its upper edge (high positioning edge) corresponding to the highest position of a predetermined deflection width (width recorded by deflection), and the shielding plate 5 is fixed with its upper edge (low positioning edge) corresponding to the highest position of a predetermined deflection width (width recorded by deflection). is fixed so that the lowest position of the predetermined deflection width corresponds to a position slightly off to the lower side. Such positioning can be achieved accurately with a retaining mechanism consisting of a link, a tension coil spring and a first adjustment screw, and a support mechanism consisting of a compression coil spring and a second adjustment screw. That is, when the first adjustment screw is tightened, the entire unit 22 will be lowered, and when it is loosened, it will be raised. First, turn the second adjusting screw to set the upper edge of the shielding plate 5 to a position slightly lower than the lowest position of the recording 1 deflection width.

The inkjet printer shown in FIGS. 1 and 2,
The configuration of the ink supply system is shown in FIGS. 3a and 3b, and the configuration of the electrical control system is shown in FIG. 4.

While FIG. 3a is a side view, FIG. 3b is an enlarged plan view of a plane passing through the ink rectilinear axis.

In FIG. 3a, the ink in the ink tank 28 is filtered through the filter 2.
4 and is sucked into the pump 26 and fed under pressure to the accumulator 4. In the accumulator 4, the pump 26
Pressure fluctuations due to suction and discharge are absorbed. For constant pressure ink, use a solenoid valve 8. The ink is supplied to the ink jet head 1 through the filter 25 and the heater 7. In the head 1, constant frequency pressure fluctuations are applied to the ink by constant frequency excitation of an electrostrictive vibrator. As a result, 3 of the ink jet heads 1
The ink ejected from the nozzles N1 to N3 (Fig. 3b) separates into ink particles at a predetermined distance from the nozzle. Charging electrodes 91 to 93 (fixed to the charging electrode plate 2) are arranged at this separation position, and at the time of one separation? ! ! When a charging voltage is applied to tM9t-93, the ink particles are charged to a polarity opposite to the voltage polarity of the charge 71i. The charged ink particles are deflected by the deflection electric field between the deflection electrodes 41,
When the head 1 is in the recording position, it collides with the recording paper 14, and when the head is in the home position, the unit 2 collides with the recording paper 14.
Head towards the second opening. Uncharged ink particles are directed to the conductive gutter 〇R for capturing non-imprinted ink particles both when the head is in the recording position and when the head is in the home position. That is, the filter 25 to the gutter R surrounded by the two-dot chain line are mounted on the scanning carriage 18, and the unit 22 is arranged to capture charged ink particles when the carriage 18 is in the home position.

When the carriage 18 is in the home position, the flight line of the ejected ink droplets leaves the edge of the recording paper 14 and the charged ink droplets are captured by the unit 22. Gutter〇R
The ink in the unit 22 is sucked by the pump 27 and returned to the ink tank 28, and the ink in the unit 22 returns to the ink tank 28 by its own weight. When ink ejection is stopped, first the pump 26 and the heater 7 are deenergized, then the solenoid of the solenoid valve 8 is deenergized, and then the pump 27 is deenergized. When the solenoid is deenergized, the solenoid valve 8 closes the accumulator 4-filter 2.
5 is cut off, and the ink tank 28 and filter 25 are communicated.

Deflection electrode 41+42+gutter〇R from nozzles N1 to N3
An enlarged front view of the recording paper 14 is shown in FIG. 3c. In this embodiment, only the nozzle 93 is used in the sub-scanning direction Y! & In that order from the largest deflection position 0 to the lowest deflection position m,
m+1 dots are recorded, but since the moving speed in the main scanning direction X is fast, the lowest deflection position m is 1 as shown in FIG.
It is recorded at the position indicated by the dotted chain line. Therefore, the highest deflection position 0 is recorded next (the cycle of recording the same point in the Y direction is d
There is a recording gap of two dots between T) and the previous recording position 0. That is, the head 1 moves in the X direction by dNn=3 dots during dT.

Therefore, three nozzles N1 to N3 are used, and nozzles N2 and N
1 fills in the blank area with the nozzle N3. In Fig. 3c, the circles indicated by grid lines are dots recorded by nozzle N3, the circles indicated by diagonal lines downward to the right are dots recorded by nozzle N2, and the circles indicated by diagonal lines downward to the left are dots recorded by nozzle N1. .

In addition, in order to prevent the printing of one line 0 to I11 in the Y direction from descending to the right, as shown in FIG. 3C, the deflection electrodes 41+4
2 and the gutter GR are arranged to be inclined downward to the right with respect to the horizontal line (X direction). As a result, nozzle N3
The recording of one line in the Y direction by
As shown in ~m, it becomes vertical. In this way, in this embodiment, blank areas in the printing record produced by only one nozzle (N3) due to the high speed of scanning of the carriage in the X direction are replaced by other nozzles (N 21 N 1). I am trying to fill it out with the printed records. Although it is a division record, the division is not an area division but a line division. Note that the nozzle arrangement pitch is larger than one recording dot pitch, so as shown in FIG. 3C, nozzle N2 is 8 dot pitches (recording dot pitch in the X direction) to the left of nozzle N1.
Nozzle N1 is shifted 16 dots to the left from nozzle N1.

During printing, from the start of printing at the row start end (left end) of nozzle N3, the printing of nozzle N2 starts after a delay of 9 dots in the X direction, and after a delay of 17 dots in the X direction, the nozzle starts printing. Recording printing of N1 is started.

FIG. 4 shows the configuration of an electrical system for controlling printing and recording. In this embodiment, a charge detection circuit 43a is connected to the charge detection electrode 13, and a charge detection circuit 43b is connected to the conductive gutter R. Charge detection circuit 43a
and 43b have exactly the same configuration.

FIG. 5 shows the configuration of the charge detection circuit 43b shown in FIG. 4. Referring to FIG. 5, there is a gap between the core wire of the shield wire 29 connecting the conductive gutter GR and the charge detection circuit 43b and the ground due to the change in insulation resistance Rg between the gutter 〇R and the ground due to ink stains on the gutter GR. In order to prevent instability in charge detection, a voltage conversion resistor R having Ω is connected to a resistor Re = 100 which is smaller than Rg. The core wire 1 of the shield wire 29 is connected to a charge detection circuit 43b. This circuit 43b includes a high input impedance field effect type 1 to transistor FET, an operational amplifier OPI,
Bypass filter HPF, integral circuit IGR for DC smoothing
and a comparator COM. This charge detection circuit 43b produces an output Pokb at a low level rOJ when charged ink particles are colliding with the gutter ○R.

The charge detection circuit 43a outputs a low level "0" output P o when charged ink particles collide with the charge detection electrode 13.
It produces ka.

6 shows the configuration of the 1 phase setting circuit 44, and FIG. 7 shows the electrical signals of each part of the circuit 44. A clock pulse Op of 1.6 MHz is applied to the 0 phase setting circuit 44, and this is applied to the counter CO1. will be counted. counter CO1
Each bit A-D of the count code output (A=first
The A bits (1 to D = 4th) are used as shift activation pulses to the serial-in/parallel-out shift register SR.
Also, the D bit is applied as an input signal. This causes the output terminals 0 to 7 of the shift register SR to have a phase of A in sequence.
Pulses with a pulse width D shifted by a period appear, one of which is outputted from the data selector DS as an excitation pulse Vp for the electrostrictive vibrator and applied to the excitation voltage generator 39.

The output bits B-D of the counter COI are applied to the decoder DE, the first output 0 and the fifth output 4 of the decoder DE.
output pulses are applied to frequency divider FD1 and T flip-flop FFI, respectively.

The Q output of the T flip-flop FFI is applied to the applied charging voltage generator 40 as a charging timing signal Cp. The pulse whose frequency is divided to 1/16 by the frequency divider FDI and shaped by the AND gate AN2 to the output pulse width of the output terminal O of the decoder DE is applied to the search charge voltage generator 41 as a phase search charge signal pulse PP. As shown in FIG. 7, the charging signal Pp has 16 consecutive pulses followed by a rest period corresponding to 16 pulses, and is intermittent at a period of 320 μsec. On the other hand, the printing charge timing signal Cp is a continuous pulse with a pulse width eight times that of the pulse Pp (high level "
1”).

In this embodiment, the phases of both the phase search charging signal pulse pp and the printing charging timing pulse Cp are fixed, and the phase of the electrostrictive vibrator excitation pulse Vp is set by the data selector DS and the count code A-C of the counter CO2. It is shifted or changed depending on which of the shift register outputs 0 to 7 is to be output. In other words, the charging voltage pulse phase is fixed and the separation phase of the ink particles is shifted.

FIG. 8 shows the configuration of the amplification gain adjustment section 40b, which is half of the printing charge voltage generator 40 shown in FIG. In this embodiment, the gain adjustment section 40b of the printing charging voltage generator 40 controls the charging voltage code generating section 40b for the other half during printing and recording.
From a (Figure 9).

The D/A converter DAI receives the charging voltage code 5ea (multiple values corresponding to the number of deflection stages) in synchronization with the pulse pp.
input and gate group ANC, and when adjusting the deflection amount, the frequency divider FD2. ANDGATE AN3. AN
4. An OR gate ORI and an inverter INI are provided.

Further, in this embodiment, since the amount of deflection is also adjusted by adjusting the charged voltage amplification gain, the resistors R1 to Rm and transistors (for selective connection) are used for gain setting.

Latch LA2 for holding gain instruction code. It is provided with a decoder DEL that converts a gain indication code into a signal for indicating conduction transistors, operational amplifiers 0PA51-3, output transistors TRI-3, and FETs 4031-3.

When FET4031-4033 is off, it is a transition.

All of the stars TRi~3 generate the voltages marked as "for recording charge" in FIG. Apply to 93. When the changeover switch SW is connected to the "phase search" side, the voltage generated by the search charging voltage generator 41 is applied to the charging electrodes 91 to 93.

Each of FET4031 to 4033 has a nozzle N1.
The inverted signals (H: non-recording, L: recording D) of the image signals assigned to ~N3 (charged electrodes 91-93) are serial-in/parallel-out shift registers 4081-4083 that store 8-bit image signals. , a multiplexer 409 that outputs the 8-bit output of the shift register one bit at a time.
1 to 4o93 and provided via an inverter. Therefore, the charging voltage generation circuit up to the resistor R of 40b is 1
A set of three nozzles N1 to N3 (charged electrode 91
~93), and three sets of FET403i~4033゜operational amplifiers 0PA51~3 and output transistors TR1~
3 is a switch means, which selectively applies a charging voltage to the charging electrodes 91 to 93 in accordance with the image signal. Referring to FIG. 9, charge code generation section 40a
is the address counter 4 that determines the ROM read address.
01. The ROM 402, 4J? stores the standard charging voltage code VC3 (Cpi, i = 1 to 32) from the 1st step to the 32nd step, codes for correcting deflection distortion due to the charging pattern, charge amount distortion, etc. ! An adder circuit 404. adds a correction value code and a distortion correction code to the quasi-charge voltage code Vcs as a deflection amount adjustment; and a latch 405.1 adds a distortion correction code to the quasi-charge voltage code Vcs; A data selector 406. supplies the output code Cpi1 of the latch 405 to the gain adjustment section 40b during recording charging, and the charging code Scc given by the microcomputer 45 to the gain adjustment section 40b when adjusting the deflection amount. Decoder 407. Latch 4 that latches the deflection amount correction code
11, and a latch 410 that latches the addition output.

FIG. 17 shows the address classification of memory data in the ROM.

From the ROM 402, the address counter 401 sequentially reads the charge distortion correction value and the standard charge code Vcs from 2 to 85 in the first step. The image signal is sequentially shifted to the shift registers 4081 to 4083 using a signal Cp synchronized with the print cycle, and during that time, the value of the shift register is shifted 8 times by the Glock pulse CLK2 with a cycle number 8 times that of CP to the multiplexers 4091 to 4093. The signals are read out sequentially and applied to FETIO31-4033 through an inverter.

Addition circuit 404 and latch 410 add only necessary correction codes. When the addition is completed eight times, a latch 405 latches the corrected charge code. At the same time, latch 41
Reset to 0 and prepare for the next addition. The reset signal is obtained by decoding the address code with a decoder 407. At the time of the next addition after the latch 410 has been reset, the data selector 411 selects the correction code from the microcomputer 45 instead of the output of the latch 410 and adds it to the addition circuit 404. As a result, the charge codes subjected to distortion correction and deflection amount correction from the first step to the 32nd step are provided to the gain adjustment section 40b via the latch 405 and the data selector 406.

Next, referring to FIG. 10, in this embodiment, the pump energizing circuit 36 is used as ink pressure setting means. That is, the ink pressure is changed by the pump energizing circuit 36 to adjust the flying speed of the ink particles, so that the flying speed of the ink is adjusted to a constant value.

Since the pump 26 is of a reciprocating type in which the plunger is driven back and forth by alternating current energization of the solenoid, the pump energizing circuit 36 changes the solenoid energizing voltage level to change the discharge pressure of the pump 26. In the circuit 36, the output voltage level of the sine wave oscillator ○SC is adjusted by the operational amplifier OP2 and applied to the output amplifier, so that the solenoid energizing voltage of the pump 26 is obtained by this output amplifier. The gain of the operational amplifier OP2 is determined by the conductivity of the transistor Tr. When the value of the gain code Gcc applied to the D/A converter DA2 is large, the conductivity of the transistor Tr is high, and the gain of OF2 is small. Therefore, the discharge pressure of the pump 26 (that is, the ink pressure) is low, and the value of the gain code Gcc is high. When is small, the conductivity of the transistor Tr is low, the gain of OF2 is large, and the discharge pressure of the pump 26 is therefore high.

FIG. 11 shows the configuration of a microcomputer unit 45 used as an electronic control device in this embodiment. The microcomputer unit 45 includes a pulse generator 451.
Microprocessor (microcomputer) 452.
Programmable ROM-(FROM) 453, 454. Memory can be erased and written with ultraviolet rays. RAM455-458 with input/output ports and timers. Programmable interactive controller 459. It consists of a program counter 460 and an address latch 461. RAMs 455 to 458 contain ink ejection control, two-phase search control, and deflection amount adjustment control.

Sensor signal lines, control signal lines, and data lines necessary for all inkjet printer controls such as recording control, carriage drive control, and recording paper feed control are connected via interfaces such as amplifiers and inverters. and PROM 453 and 45
4, program data for executing the inkjet printer control is written.

Figure 13 shows the control outline (main flow) of inkjet printer control based on the program data.
FIG. 4 shows the WtI 118 for recording control, FIG. 15 shows details (subflow) of phase search control, and FIG. 16 shows details (subflow) of deflection amount adjustment control.

First, an overview of inkjet printer control will be explained with reference to FIG.

When the power is turned on, the microcomputer unit 45 (hereinafter referred to as the microcomputer 45).

Read the beginning of the control program, initialize the input/output ports, and set the printer stop timing state (ink ejection stop, deflection voltage cutoff). Next, the carriage 18 is positioned at the home position (the position where the head 1 faces the electrode 13 of the unit 22).

Next, the status of the ink supply system is determined by referring to the signals of the sensors in each part, and if there is an abnormality, the status corresponding to the abnormality is displayed and the abnormality is repaired. The on-off valve 8 is energized to establish communication between the accumulator 4 and the filter 25, and the standard gain code Gcc is output set to the D/A converter DA2 of the pump driver 36 to drive the pump 26.
7 and instructs the heater driver 38 to control the ink temperature. Then, the 1 sec timer is turned on, and then the 30 sec timer is turned on, and the ink pressure adjustment setting is started.

1 When the s'i=c timer times out, the AND gate 462 (see Figure 11) is opened and the 1.6MII
The clock pulse OP of z is output set to the phase setting circuit 44. As a result, an excitation clock pulse VP is applied to the excitation voltage generator 39, the electrostrictive vibrator of the head 1 vibrates, and pressure vibration is applied to the ink within the head 1. head l
This causes the ink jetted to separate into ink particles and fly, colliding with the gutter GR.

When the 30 sec timer times out, the ink pressure has stabilized at a predetermined pressure that allows ink particles to fly at a predetermined speed, and the microcomputer 45 performs a phase search, then sets the deflection amount, and proceeds to the primary recording control. When recording is completed, ink jetting is stopped and an ink jetting instruction is input.

When entering recording control, the microcomputer 45 turns on an 80 sec timer, and when the timer expires, the process proceeds to phase search when the recording reaches a predetermined break, then proceeds to deflection amount setting, and when these are completed. The 80 sec timer is turned on again to return to recording control, and when the 80 sec timer times out, phase search and deflection amount setting are performed in the same manner.

Next, phase search control will be explained with reference to FIG.

When proceeding to the phase search, the microcomputer 45 closes the switch SW to the charging electrode 9-search charging voltage generator 41 connection side, and turns on the deflection voltage power source. Then wait for 10m5ec to pass. By connecting SW to the search charge voltage generator 41 side, a search charge pulse obtained by amplifying the search charge pulse Pp (see FIG. 6) is applied to the electrodes 91 to 93. Namely.

A phase search charging pulse having a period of 10 μsec, which is intermittent at a period of 320 μsec, is applied from the search charging voltage generator 41 to the charge 'rr1Y1 pole 9 via the switch SW. - way,
Now, suppose the count code of counter CO2 is ro OO
J, the pulse at the output terminal 0 of the shift register SR is applied to the excitation voltage generator 39 as an excitation pulse Vρ, and the ink particles are generated at a phase corresponding to the period and phase of this Vρ (phase with respect to Pp). To separate. When the ink particles are separated at the same timing as the pulse pp, the ink particles are negatively charged and, since no deflection voltage is applied, go straight and collide with the conductive gutter R. In other words, the ink particles separated at the period of the pulse Pp produce a charging pattern with a period of 320 μsec in which 16 consecutive particles are negatively charged and the next 16 particles are uncharged, and the charged ink particles collide with the gutter R. Therefore, in this case, the potential of the gutter GR causes potential fluctuations similar to the charging pattern.

However, due to the stray capacitance of the shield wire 29 of the charge detection circuit 43b and the time constant of the resistor R, the FET of the charge detection circuit 43b
The base potential causes a sinusoidal or envelope-like potential fluctuation with a period of 320 μsec.

Such a sine wave voltage is inverted by the FET, further inverted and amplified by the operational amplifier ○P1, and is applied to the bypass filter HPF at a positive level. The bypass filter blocks noise with a period of less than 320 μSet.

The integrating circuit IGR smoothes the 320 μsec period sine wave and stabilizes it to a constant DC level.

This DC voltage is compared with a reference voltage in a comparator COM, and when the DC voltage is higher than the reference voltage, ie.

When the ink droplets are charged, the output of the comparator P o
When kb is at a low level "0" and the ink particles are uncharged or incompletely charged, the comparator output P
okb is a high level "1". The output of this comparator P
okb is applied to the microcomputer 45 and also to the AND gate ANI of the phase setting circuit 44.

In summary, if the ink droplet separation phase matches the pulse pp, the ink droplet will be charged, but if it does not match, the ink droplet will not be charged. If the ink particles are charged, the output Pokb of the charge detection circuit 43b becomes a low level "0", but if the ink particles are not charged, it remains at a high level "1". When 10 m5ec has elapsed, the microcomputer 45 refers to the detection output Pokb of the charge detection circuit 43b, and searches if Pokb is at a low level "0".Since the separation phase of the ink particles is appropriate with respect to the phase of the charge voltage pulse, the counter Clear the category and flag and proceed to the deflection amount setting. but,
When P okb is at a high level "1", the separation phase of the ink particles is out of phase with the phase of the search charging voltage pulse, and proper charging is not performed, so the microcomputer 45 sets the shift counter (program counter) to one count. It's up,
A Pdkl pulse is given to the phase setting circuit 44. In the phase setting circuit 44, when the Pdkl pulse is applied, the counter C2 counts up by one, and the phase of the particulate excitation pulse VP is shifted by one step. That is,
The counter C2 counts up by 1, and the output VP of the data selector DS changes from the pulse at the output terminal i of the shift register SR to the pulse at the output terminal i+1.

The naori counter C○2 counts @ return, and if the ink jetting is normal, when the pulse of any one of the output terminals 0 to 7 of the shift register SR is given as VP to the excitation voltage generator 39, that is, During one cycle=eight phase shifts, the ink droplets are charged, and the output Pokb of the comparator COM of the charge detection circuit 43b becomes "0".

When the microcomputer 45 gives the PdkL pulse to the circuit 44,
Set the 10m5ec timer and wait for 10m5ec to elapse. When 10 m5ec has elapsed, Pokb is referenced, and if Pokb is "0", the process proceeds to setting the deflection amount, but if it is "1", the shift counter is counted up by 1, and a Pdkl pulse is given to the phase setting circuit 44.
Set the 50C timer. In this way, the microcomputer 45 detects that the output Pokb of the charge detection circuit 43b is at a low level "0".
A count-up pulse Pdk is applied to the phase setting circuit 44 until it reaches . When the count value of the shift l-counter reaches 8, it means that proper charging was not performed in any of the ink droplet separation phase shifts of one cycle, so the microcomputer 45 sets the number counter (program counter) to one count. rise. Then, the microcomputer 45 performs a phase search for the next cycle in the same manner as described above.

If proper charging is not performed in the next cycle, the microcomputer 45 further increments the number of times counter and performs a phase search for the next cycle. Therefore, the contents of the number counter are such that eight ink droplet separation phase shifts constitute one cycle. Shows the number of execution cycles.

In this embodiment, if Pokb does not become "0" (charging suitable) even after 10 cycles of phase search, it is assumed that an ink jetting error has occurred, an ink jetting error flag is set, the number of times counter is cleared, and a 60 sec timer is turned on. Then, the process proceeds to the main flow (FIG. 13) of stopping ink ejection.

To stop ink ejection, the microcomputer 45 cuts off the deflection voltage, stops the pumps 26 and 27, turns off the electromagnetic on-off valve 8 (accumulator 4 - ink tank 28 connection), turns off the heater driver 38, and turns off the AND gate 462.
is off. That is, the microcomputer 45 stops ink ejection and cuts off the charging voltage and excitation voltage. 60s after that
Wait for the ec time to elapse. When 60 seconds have elapsed, the microcomputer 45 proceeds to the initialization of the main flow (FIG. 13), and after passing through the main flow, starts the phase search (FIG. 15) again.
Figure). In the next phase search, if P okb does not reach the low level "0" after 10 cycles of phase search,
Since the ink ejection abnormality flag is set, the microcomputer 45 sets an abnormality display, resets the ink ejection flag, clears the number of times counter, and proceeds to stop ink ejection.

Since the ink jetting abnormality flag is not set when the ink jetting is stopped this time, the microcomputer 45 stops ink jetting and continues to display the abnormality until an jetting instruction is input.

In this state, when an ink ejection instruction is given by an operator input, the microcomputer 45 resets the abnormality display and proceeds to the initialization of the main flow.

When Pokb becomes a low level "0" during the second ink ejection and phase search, it means that the ink ejection has become normal and proper charging has been set, so the shift counter, number of times counter, and ink ejection abnormality flag Clear it and proceed to the deflection amount setting.

Next, the deflection amount setting will be explained with reference to FIG.

When proceeding to the deflection amount setting, the microcomputer 45 instructs the deflection voltage power supply circuit 42 to turn on the deflection voltage, and at the standard gain, the charged ink particles collide with the electrode 13 even if they are deflected. The standard charging code of the deflection stage) is set as the charging code See at the output port and is given to the data selector 406, and the data selector 406 is instructed to output the code See, and then,
The standard gain code is outputted to the gain adjustment section 40b as a gain code Sgc, and latched into the latch LA2.

Also.

The gate signal DGc given to the gain adjustment section 40b is set to a low level rOJ, and the AND gate AN2 is turned off.
Turn on. Then, a recording (charging instruction) level "1" is given to the shift register 408 as an image signal. This means that the charge deflection is set. and 10cs
Set the ec timer (program timer) and wait for it to time out. When the time is over, the charge detection circuit 4
3a, and if it is "0" indicating that the charged ink particles collide with the electrode 13, the charging code S is determined.
cc is updated to a code with a value one step higher than the previous value, and a 10 csec timer is similarly set, and when the time elapses, Poka is referenced again. Below this is P
This process can be repeated until "oka=r l".

When Poka= r I J, the charge code at that time is 5
cc32 d is memorized, and this time the charge code Scc is 5
cc1 +d (Sccl is the charging code of the first stage deflection), a 10m5ec timer is set, the ink particles are charged in the same way, and the timer timeout is waited.

When the time is over, the charge detection circuit 43a output P OK
a, and if it is "0" indicating the collision of ink particles to the charge detection electrode 13, the charge code is changed to 1 from the previous value.
Set the step to a small value and set the 10m5ec timer, and when the timer times out, refer to Poka again. Repeat this below, Poka= r IJ
(The ink particles now collide with the shielding plate 5)
When this happens, the charge code 5cc1d at that time is stored in memory.

The above means that the required data has been detected. Next, the microcomputer 45 calculates the charge code correction value ΔS cci for each deflection stage using the following equation, and stores it in the correction value register.

Δ5cci=(Sccld-5cc1)+(i 1)
・((Scc32 d 5cc32 )−(Scc
l d-3ccl))/311: Deflection stage No.; 1
~32 Next, the data selector 406 is set to a mode for outputting the output of the latch 405, and the process returns to the main routine shown in FIG. 13 to proceed to recording control.

During recording control, the charge amplification gain is set to the standard gain,
The deflection amount correction amount is set to ΔS cci at each stage, and the standard charge code Vcs (
Cpi, i = 1 to 32).

Note that out of 16 consecutive ink particles (160μ5ec), 8 ink particles are charged one after another, and the next 16 consecutive particles (160μ5ec) are charged.
μ5eC) is a charging pattern in which one period is 320 μsec in which the battery is uncharged. Note that during phase search, a charging voltage (corresponding to Pp) is applied to charge 16 consecutive ink particles, but when adjusting the deflection amount, pulse C is applied.
A charging voltage synchronized with p is applied, and Cp is 1/2 of pp.
The frequency of the ink particles is 1 per pulse Pρ.
Please pay attention to the fact that it is generated individually. In this way, even when adjusting the amount of deflection, charging is performed using a charging pattern with one period of 320 μSec.

When the above-mentioned ink ejection setting control 9 phase search control and deflection amount setting control are normally completed, the microcomputer 45 responds to the printing start command and proceeds to recording control. In this recording control,
Since DGo=rlJ is set, the AND gate AN4 is open and AN3 is closed in the printing charge voltage generator 40, and the recording charge signal Cp appears as is at the output terminal of the OR gate ○R1. In this recording charge control, the microcomputer 45 turns on the 80 sec timer as mentioned above, and when it times out, it interrupts the recording charge control when the recording reaches a predetermined break, and the main controller shown in FIG. Proceeding to the next step after initializing the flow, check the status of each part, perform phase search control and deflection amount setting control, and when these are completed normally, turn on the 80 sec timer and return to recording control, and when the 80 sec timer times out Then, the process described above is executed, and this process can be repeated from now on.

An overview of this recording control will be explained with reference to FIG.

When proceeding to recording control in response to the print start command, the microcomputer 45
refers to the detection signal of the home sensor (HP) to check whether the carriage is at the home position or not, and if not, drives the carriage to the home position. Next, perform a phase search. This is exactly the same as shown in FIG. In addition,
When proceeding to recording control for the first time after turning on the power, as shown in Figure 13, it is unnecessary because phase search has already been executed before recording control, but after proceeding to recording control, it is necessary to perform a phase search for each line of recording. In order to perform a phase search and monitor phase suitability, the phase search is first performed.

When the phase search is completed, a voltage-on instruction is given to the deflection voltage power supply circuit 42 to apply a deflection voltage to the deflection electrode 41. Then, the carriage 18 starts recording. When the detection signal of the print sensor (RPS) indicates the arrival of the carriage (when the carriage reaches the beginning of the recording area),
Start printing.

When one line of printing is completed, the print start command disappears, and in response, the microcomputer 45 instructs the deflection power supply circuit 42 to cut off the deflection voltage, and proceeds to carriage stop control. When the carriage is stopped, it is checked whether a line feed command has arrived, and if so, a line feed (feeding the recording paper by one line width) is executed, and then the process proceeds to carriage return control. When this is completed, it is checked whether the deflection amount adjustment timing has come, and if so, the process proceeds to the phase search in the main routine (FIG. 13). If it is not time to adjust the deflection yet,
It is checked whether or not a print start command has arrived, and if it has arrived, the process returns to the beginning of recording control and performs recording control in the same manner as described above. If the print start command has not arrived, it is checked whether or not a print end command has arrived, and if it has arrived, the process proceeds to stop ink ejection as shown in FIG. 13. If neither a print start command nor a print end command has arrived, the process returns to checking whether a line feed command has arrived, and the line feed command and print start command are referred to below.

Wait for the arrival of a termination order, etc. While waiting, when the deflection amount adjustment timing comes, the program proceeds to phase search in the main routine (FIG. 13).

The control timing in the recording control explained above is
Shown in Figure 2a. In this example, the deflection voltage executes a phase search in response to a print command, and after completing the phase search, the carriage 18 is caused to travel and the deflection voltage is turned on. There is a delay time before the deflection voltage actually reaches the specified voltage.
Since the deflection voltage has risen to a predetermined value by the time the carriage 18 reaches the pre-position 21 (RPS), no trouble occurs in printing. Further, since the carriage 18 is stopped during the phase search, search errors due to head vibrations do not occur, and the phase search accuracy is high. Incidentally, when the deflection amount adjustment timing is reached and a print start command is received while the phase search and deflection amount setting are proceeding, the recording control timing becomes as shown by the two-dot chain line in FIG. 12a. In any case, the deflection voltage is 1 only from the end of phase search until the end of printing! The polarity is applied to the pole 41, so that no search error occurs due to leakage noise of the deflection electrode during phase search. In this way, the deflection voltage is cut off during phase search.

The charging voltage in phase search is as shown in Figure 12b,
Record load? ! The polarity is the same as the voltage.

In the above embodiment, the phase of the charging voltage pulse is fixed and the ink droplet separation phase is shifted to perform a phase search to properly charge the ink droplets. It may be fixed and the phase of the charging voltage pulse may be shifted to properly charge the ink droplets.

In the charging voltage generator 40 (40a+40b), there is one set of charging voltage generation circuits that generate charging voltages corresponding to the printing position in the Y direction from address counter 401-[anti-Ri, R□ in a stepwise manner. Voltage, FET4031
, an operational amplifier 0PA51, and a first switch circuit consisting of an output transistor Tr1, an FET4032, an operational amplifier 0PA52, and an output transistor Tr1.
2 and a second switch circuit consisting of F[ET40
33. Operational amplifier 0PA53. and a third switch circuit consisting of an output transistor Tr3 applies the voltage to the charging electrodes 91, 92 and 93 when the image signal indicates recording. A charging voltage generation circuit that generates charging voltages corresponding to printing positions in the Y direction from address counter 401 to resistors Ri and R1 in a stepwise manner is a circuit element for generating stepwise voltages and a circuit element for phase search. Since the configuration is complicated, including only one set of circuits, the configuration of the inkjet recording apparatus can be simplified and the cost can be reduced.

In the above embodiment, the microcomputer 45 directly supplies the deflection voltage on/off instruction signal to the deflection voltage power supply circuit 42 in accordance with the timing signals of each part.
As shown in FIG. 8, a logic circuit may be provided to control turning on and off of the deflection voltage power supply circuit 42 in response to timing signals of each part.

In the example shown in FIG. 18, the flip-flop FF2 is set by the phase search end signal to give a deflection voltage ON instruction to the deflection voltage power supply circuit . When there is a print end signal and a carriage stop signal arrives, the AND gate AN5 resets the flip-flop FF2 via the NOR gate NRI, and the flip-flop FF2 outputs the deflection voltage power supply circuit 4.
2 gives a deflection voltage off instruction. Further, when there is a deflection amount adjustment end signal but there is no print start signal, AND gate AN6 resets flip-flop FF2 via NOR gate NRI, and flip-flop FF2 gives a deflection voltage OFF instruction to deflection voltage power supply circuit 42. Therefore, in this example, the deflection voltage is applied to the electrode 41 after completing the phase search until the carriage stops at the turning point after printing one line. The deflection voltage is off until the carriage returns from the turning point, stops at the home position, and then completes the phase search. When setting the deflection amount, the deflection voltage is turned on, and when there is no subsequent recording control, the deflection voltage is turned off. In this example, the tasks of the microcomputer 45 are reduced.

■Effects As explained above, the present invention requires only one set of relatively complicated charging voltage generation circuits in performing recording control by individually charging and controlling the ink ejected from each of a plurality of nozzles. The hardware becomes simple and the device cost can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the main part of a pier of a recording apparatus embodying one embodiment of the present invention, and FIG. 2 is a side view. Figure 3a is a system diagram showing an overview of the ink supply system and ink@ring system of the same device, and Figure 3b is a diagram showing the head 1 in a horizontal plane.
FIG. 3c is an enlarged plan view showing a cutaway view of the nozzles N1 to
Looking at the gutter OR direction from the N3 side. FIG. FIG. 4 is a plot diagram showing the configuration of the electrical system of the device. 5 is a block diagram showing the configuration of the charge detection circuit 43b shown in FIG. 4, FIG. 6 is a block diagram showing the configuration of the phase setting circuit 44 shown in FIG. 4, and FIG. 7 is a block diagram showing the configuration of the phase setting circuit 44 shown in FIG. 8 is a block diagram showing the configuration of the gain adjustment section 40b of the printing charge voltage generator 40 shown in FIG. 4, and FIG. 9 is a time chart showing the printing charge voltage generator 40 shown in FIG. 4. A block diagram showing the configuration of the charge code generating section 40a of the device 40, FIG. 10 shows the pump driver 36 shown in FIG.
11 is a block diagram showing the structure of the microcomputer unit 45 shown in FIG. 4. FIG. FIG. 12a is a time chart showing one aspect of the deflection voltage control of the present invention, and FIG. 12b is a signal waveform diagram showing the main voltage polarity in phase search and recording used together with the deflection voltage control. FIG. 13 is a flowchart showing an overview of the inkjet printer control operation of the microcomputer unit 45 shown in FIGS. 4 and 11, FIG. 14 is a flowchart showing an overview of the recording control operation, and FIG. 15 is a flowchart showing the phase search control operation. , FIG. 16 is a flowchart showing the deflection amount setting control operation. FIG. 17 is a plan view showing address divisions of data written in the ROM 402 shown in FIG. 9. FIG. 18 is a block diagram showing the configuration of main parts implementing the present invention in another embodiment.

Claims (2)

[Claims] (1) A plurality of nozzles; an ink supply means for supplying pressurized ink having pressure vibrations to each nozzle; a plurality of charging electrodes, each of which selectively charges the ink ejected from each nozzle; a deflection electrode that deflects; a gutter that captures non-deflected ink particles; a set of charging voltage generating means that periodically generates a charging voltage corresponding to the printing position that is switched in units of cycles of the pressure vibration; and the charging voltage. selectively supplying the charging voltage generated by the generating means to each nozzle according to the image signal assigned to each nozzle;
A multi-nozzle inkjet recording device comprising: a plurality of switch means; (2) The direction of the deflection is the sub-scanning direction Y, the period of printing ink droplets at the same point in the sub-scanning direction Y is dT, and the period of dT in the main scanning direction X perpendicular to the sub-scanning direction Y is The movement of the nozzles between them is dNn dots, and the number of nozzles is N.
The multi-nozzle inkjet recording apparatus according to claim (1), where Nn=dNn.