JPS58114968A - Deflection control type ink jet recording apparatus - Google Patents

Abstract

PURPOSE:To prevent unstable detection of deflection due to an ink stain by a method wherein a plate charge detection electrode is provided with resistor means, a charge detection circuit, deflection retrieval voltage generating means and ink pressure setting means. CONSTITUTION:A resistor having a resistance smaller than insulation resistance and used to connect a plate charge detection electrode to a predetermined potential point is connected across the core wire and a ground of a sealed wire connected to the plate charge detection electrode in a gutter. Then a charge detection circuit 23 for detecting a discharge passing through a resistor means of charged ink particles caused to collide with the plate charge detection electrode is connected to the core wire of the sealed wire. Moreover a printing charge voltage generator 20 as deflection retrieval generating means generating charge voltage changed over from a charge level to a non-charge level in a period longer than what generates the ink particles and a pump energizing circuit 16 of ink pressure setting means are connected thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention jets pressurized ink from a nozzle, applies vibration to the jetted ink to form ink particles regularly, and selectively generates ink particles based on the image mark when the ink particles are generated. The present invention relates to deflection control type inkjet recording in which a charging electric field is formed, ink particles are charged with this electric field, and the charged ink particles are deflected by a deflection electric field, and particularly relates to deflection control for causing ink particles to fly in a predetermined deflection trajectory.

In this type of inkjet recording, the distance from the ink jetting nozzle to the recording paper is relatively long, and therefore the ink pressure remains constant even though the ink particles ejected from the nozzle and turned into particles are affected by a charging electric field and a deflection electric field. It is set high so that it reaches the recording paper on a stable flight trajectory. In addition, in order to regularly generate ink particles with a predetermined particle size and to make them accurately take a predetermined deflection trajectory, ink viscosity, ink pressure, vibration pressure, charge amount, deflection electric field, etc. must be stabilized. and must be precisely controlled.

For this reason, U.S. Pat. No. 3,787,882 proposes controlling ink pressure by detecting at least one of ink pressure, temperature, ink flight speed, and deflection amount. . However, in controlling the deflection position of ink particles, that is, controlling the printing point, for high-density recording such as 4 dots/1 ml and 8 dots/Im,
Deflection control must be performed extremely finely, and control of only ink pressure is still insufficient in stability, precision, and responsiveness. Therefore, the present inventor proposed to perform deflection control by adjusting the charging voltage level and the deflection voltage level (Japanese Patent Application No. 53-140798, Japanese Patent Application No. 53-1418).
No. 36 and Japanese Patent Application No. 55-18914, etc.). In this voltage level adjustment, while the deflection position of the ink droplet is out of a predetermined position, the charging voltage level and/or deflection voltage level is moved step by step in the direction of moving the ink droplet to the predetermined position, and each time the voltage level is changed, Detecting the deflection position of the ink droplets. Other methods include adjusting the excitation voltage, ink temperature, or ink pressure.

In the above patent application, a charge detection electrode plate and an integrating circuit are used to integrate the electric charge when a charged ink droplet contacts the charge detection electrode plate, and the integrated voltage during the time when a predetermined number of ink particles arrive is equal to or greater than a predetermined value. If so, it is determined that the charged ink particles are hitting the charge detection electrode plate. The charge detection electrode plate is installed in a gutter that captures non-printing ink particles during recording control, or in a separately provided gutter that captures ink particles that come off the gutter when the ink jet head is in the home position. . Since the electric charge that one ink particle has is extremely small, approximately 0.8 x 10" coulombs, consideration is given to insulating the charge detection electrode plate. However, if the ink is attached to the charge detection electrode plate or the gutter, Ink splashes caused by particle collisions stain the insulator surface that supports the gutter, and this stain causes leakage between the gutter and the collected ink, making the capacitor voltage of the integrating circuit unstable and causing charge detection to become unstable. Especially when the dirt is severe, it is determined that there is no charge even if it is properly charged.

To solve this problem, it is necessary to keep a part of the rattle clean at all times, which is difficult to manage. Furthermore, in this charge detection, due to the frictional charging of the ink as it is ejected from the nozzle and the generation of charges when the ink particles collide with the gutter, it is possible to detect charges that are unrelated to charging or non-charging due to the voltage of the charging electrode of the ink particles. The charge detection signal is charged to the capacitor as a DC bias, and S
/N is low, it is necessary to increase the number of charged ink particles in order to prevent false detection, and it takes a long time to set an appropriate deflection amount.

The first object of the present invention is to improve detection instability caused by ink stains in deflection detection using a plate-shaped charge detection electrode, and the second purpose is to shorten charge detection time. The purpose of step 3 is to stably set the deflection amount to a predetermined set value.

In order to achieve the above object, in the present invention, a plate-shaped charge detection electrode is arranged adjacent to a predetermined charged ink particle deflection locus, and is connected to ground, which is a reference potential, through a resistor or other resistor. It is also connected to the charge detection circuit. In deflection detection, a charging voltage is repeatedly applied and cut off to the charging electrode at a predetermined cycle TD that is longer than the ink droplet generation cycle to charge a predetermined number m of generated ink particles (however, skipping one or several particles) (including electric charge),
A charged pattern is formed in which the next n pieces are uncharged. By this, and when a resistor and, if necessary, a parallel capacitor is connected, by appropriately setting the electrical quantity of the capacitor, when a charged ink particle is colliding with a plate-shaped charged detection electrode, a plate-shaped Along with the stray capacitance of the charge detection electrode, a pulsating voltage appears on the resistor with one cycle of frost in the first period.When no charged ink particles collide, no pulsating voltage appears, and the constant DC voltage (earth level including)
Or a slight reverse polarity pulsating voltage due to electrostatic induction. The charge detection circuit extracts only the pulsating voltage component through a filter, integrates it, and compares the integrated voltage with a predetermined value to determine whether or not charged ink particles are colliding with the plate-shaped charge detection electrode. In this way, the discharge current of the resistor connected to the plate-shaped charge detection electrode is detected in an alternating current manner, so even if there is ink stain and conduction occurs between the gutter and the collected ink,
By setting the resistance value of the resistor to a value sufficiently lower than the resistance value of the ink, the discharge current flowing through the resistor will not be significantly reduced and will not become undetectable. In addition, in the present invention, the ink pressure is set in conjunction with the ink pressure adjustment to detect the deflection so that the ink particles charged with a predetermined charging voltage follow a predetermined deflection locus.

FIG. 1 shows the main mechanical elements of one embodiment of the invention, and FIG. 2 shows the main electrical elements. First, refer to FIG. In FIG. 1, ink in an ink tank 1 is sucked by a pump 3 through a filter 2 and is pumped to an accumulator 4. Pressure vibrations caused by suction and discharge of the pump 3 are absorbed in the accumulator 4.

For constant pressure ink, use a solenoid valve 5. Filter 6 and heater 7
The ink is supplied to the ink jet head 8 through the ink jet head 8.

In the head 8, a constant frequency pressure vibration is applied to the ink by constant frequency excitation of an electrostrictive vibrator. As a result, the ink ejected from the inlet nozzle of the ink ejecting head 8 separates into ink particles at a predetermined distance from the nozzle. A charging electrode 9 is arranged at this separation position, and when a charging voltage is applied to the electrode 9 at the time of separation, the ink particles are charged to a polarity opposite to the polarity of the charging voltage. The charged ink particles are connected to a deflection electrode 10,
．． 10. The head is deflected by the deflection electric field between
When the head is at the home position, it collides with the recording paper 26, and when the head is at the home position, it heads toward the gutter 12. Uncharged ink particles are present in the gutter 1 both when the head is in the recording position and when the head is in the home position.
Head to 1. That is, the filter 6 through the gutter 11 enclosed by the dash-dotted line are mounted on the scanning carriage, and the gutter 12 is positioned to capture charged ink particles when the carriage is in the home position. When the carriage is at the home position, the flight line of the ejected ink droplets deviates from the edge of the recording paper 26, and the charged ink droplets are captured by the gutter 12. The ink in the gutter 11 is sucked by the pump 27 and returned to the ink tank 1, and then transferred to the gutter 12.
The ink returns to the ink tank 1 by its own weight. When ink ejection is stopped, first the pump 3 and heater 7 are deenergized,
The solenoid of the solenoid valve 5 is then deenergized, and then the pump 27 is deenergized. The solenoid valve 5 disconnects the accumulator 4 and the filter 6 and connects the ink tank 1 and the filter 6 by deenergizing the solenoid.

A plate-shaped charge detection electrode 13 is insulated and supported in the gutter 12.
There is. A shield wire 14 is connected to this electrode 13.

An electric circuit shown in FIG. 2 is connected to terminals A'-N shown in FIG. It should be noted that the terminals A to N are shown for convenience and that such intermediate terminals are not necessarily required.

FIG. 3 shows the charge detection circuit IN! shown in FIG. The configuration of r23 is shown. Referring to FIG. 3, there is a wire between the core wire and ground of the shield wire 14 to prevent instability in charge detection due to fluctuations in the insulation resistance RG between the electrode 13 and the ground due to ink stains on the inner wall of the gutter 12. , resistance RC smaller than RG! A voltage conversion resistor R having a resistance of Ω is connected to -1100. A charge detection circuit 23 is connected to the core wire of the Nord wire 14 .

This circuit 23 includes a high input impedance field effect transistor FET, an operational amplifier OP1. Bypass filter HPF, integral circuit IGR for DC smoothing, and comparator C
It is composed of OM.

FIG. 4 shows the configuration of the phase setting circuit 24, and FIG. 5 shows the input/output timing of each part thereof. Referring also to FIG. 5, a 1.6 MHz clock pulse OP is applied to the phase setting circuit 24, and this is counted by the counter COI. The A pits of each pit A-D (A-1st digit to D=4th digit) of the count code output of the counter COI are used as shift activation pulses to the serial-in-parallel-out shift register SR, and the D bit is input. Applied as a signal. As a result, the output terminals 0 to 0 of the shift register SR
7, pulses with a pulse width of D whose phase is shifted by A period appear, one of which is outputted as an electrostrictive vibrator excitation pulse V from the data selector DS and sent to the excitation voltage generator 19.
is applied to

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 FDI and T-flip-flop FF, respectively.

The Q output of the T-flip-flop FF is applied to the applied charging voltage generator 20 as a charging timing signal q. A with frequency divider FDI. The pulse, which is frequency-divided and shaped by AN2 to the output pulse width of the output terminal O of the decoder DE, is applied to the search charge voltage generator 21 as a phase search charge signal pulse PP.

As shown in FIG. 5, the charge signal P has a period of 16 consecutive pulses, followed by a rest period of 16 pulses, and has a pulse rate of 320 μSe.
It is intermittent with a period of c. On the other hand, the printing charge timing signal C2 is a series of pulses P and 8.
It has twice the pulse width (high level rlJ).

In this embodiment, the phases of both the phase search charging signal pulse P and the printing charging timing pulse CP are fixed, and the phase of the electrostrictive vibrator excitation pulse v1 is determined by the count code A of the counter CO2 by the data selector DS. The shift or main change is made depending on which one of the shift register outputs O to 7 is to be output in accordance with C.

In other words, the charging voltage pulse phase is fixed and the ink droplet separation phase is shifted.

Next, phase search will be explained. At the time of phase search, the carriage is placed at the home position, the charging voltage changeover switch SW is closed to the search charging voltage generator 21 side, and the deflection voltage power supply circuit 22 is energized (switched on). In this state, 10μsec intermittent at 320μsec period
A negative constant level charging pulse synchronized with the phase search charging pulse P of period c is applied from the search charging voltage generator 21 to the charging electrode 9 via the switch SW. On the other hand, if the count code of the counter CO2 is ro, OOJ, the pulse at the output terminal O of the shift register SR is applied to the excitation voltage generator 19 as an excitation pulse V, and this V, The ink particles are separated at a phase corresponding to the period and phase (phase with respect to PP). When the separation of the ink particles is timed with the pulse PP, the ink particles become positively charged and collide with the electrode 13 of the gutter 12. In other words, the ink particles separated at the pulse cycle 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 all the ink particles collide with the plate-shaped charge detection electrode 13. do. Therefore, in this case, the potential of the electrode 13 causes potential fluctuations similar to the charging pattern. However, due to the stray capacitance of the shield line 14 and the time constant of the resistor R, the base potential of the FET of the charge detection circuit 23 causes a sine wave-like or envelope-like potential fluctuation with a period of 320 μsec. Such a sine wave voltage is inverted by the FET and further transferred to the operational amplifier OPI.
It is inverted and amplified by the bypass filter HP at the positive level.
applied to F. The bypass filter HPF has a period of 32
Noise of less than 0 μsec is transmitted to Europe. 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, that is, when the ink droplets are charged, the output of the comparator COM is set to a low level.
0'', and when the ink particles are uncharged or incompletely charged, the output of the comparator COM is at a high level ``0''.
1”.

The output of this comparator COM is given to the printing control unit 25 and also to the phase setting circuit 24.
is applied to The printing control unit 25 is a J switch SW.
21 side, a search judgment pulse PDK is applied to the circuit 24 (Antega) ANI at a cycle of 10 m5ec, and the output P of the comparator COM is applied. When K becomes "0" (ink particle charge detected), the output of the PDK every 1Qmsec is stopped, and the process moves to deflection detection/deflection amount setting control (deflection amount adjustment). Therefore, while the output of the comparator COM is "1" (ink is not charged), one pulse is given to the counter CO2 from the AND gate ANI every 10 m5ec, the counter CO2 increases by one count, and the output VP of the data selector DS changes from the pulse at the output terminal B of the shift register SR to the pulse at the output terminal i+1 (that is, the phase is shifted by one step). Counter CO2 counts circulation,
When any of the output terminals 0 to 7 of the shift register SR is applied as a pulse V to the excitation voltage generator 19, the ink particles are charged, and the output of the comparator COM becomes "0".

After completing the phase setting, the printing control unit 25 adjusts the amount of deflection. The structures of the printing charge voltage generating circuit 20 and the pump energizing circuit 16, which are related to the adjustment of the amount of deflection, are shown in FIGS. 6 and 7, respectively.

First, referring to FIG. 6, in this embodiment, the printing charging voltage generation circuit 20 generates a charging voltage code SCC (a plurality of values corresponding to the number of deflection stages) from the unit 25 in synchronization with the pulse PP during printing and recording. /A converter DAI input and gate group ANC is switched and set, and when adjusting the deflection amount, in order to form a charge pattern in the same way as when searching the phase,
Division period FD2° and gate AN3. AN4. It is equipped with an OR gate ORI and an inverter ■N1.

Next, referring to FIG. 7, in this embodiment, the pump energizing circuit 16 is used as ink pressure setting means.

The pump 3 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 16 changes the solenoid energizing voltage level to change the discharge pressure of the pump 3. In circuit 16, a sine wave oscillator o
The output voltage level of the sc is adjusted by the operational amplifier OP2 and applied to the output amplifier to obtain the solenoid energizing voltage of the pump 3. The gain of the operational amplifier OP2 is determined by the conductivity of the transistor Tr. D/A converter DA2
Gain code G applied to. When the value of 0 is large, the conductivity of the transistor Tr is high, the gain of OF2 is small, and therefore the discharge pressure of the pump 3 (that is, the ink pressure) is low, and the gain code is G. If the value of 0 is small, the transistor Tr
The conductivity of OF2 is low, the gain of OF2 is large, and therefore the discharge pressure of the pump 3 is high.In addition, when a constant level of charging voltage is applied to the electrode, the deflection amount is large when the ink pressure is low, and the ink pressure Note that the higher the value, the smaller the amount of deflection. That is, the gain code G given to the pump energizing circuit 16. When 0 is a large value, the amount of deflection is large, and when 0 is a small value, the amount of deflection is small.

FIGS. 8a and 8b show phase search and deflection amount setting control performed by the printing control unit 25. First, the 8th
Referring to figure a, the carriage is positioned at the home position, the pumps 3 and 27 are driven, the solenoid valve 5 is opened, and the pump energizing circuit 16 is turned on. . After setting the standard gain code, the printing control unit 25 sets a preparation timer (program timer) and starts reading the status of each part.

When each part is in a recordable state and the preparation timer times out, the printing control unit 25 enters phase search and deflection amount adjustment as shown in FIG. 8a. Note that the ink pressure usually stabilizes at a certain value before the preparation timer times out. Upon entering the phase search and deflection amount adjustment, the printing control unit 25 switches the SW
Close the search charge voltage generator 21 side and set the 10m5ec timer. By this, as already explained,
When charging voltage pulses synchronized with the phase search pulse pp shown in FIG. 5 are applied to the charging electrode 9, and the ink particles are charged by them, a potential fluctuation of one cycle of 3201 tsec is applied to the charging detection circuit 23. The unit 25 detects the charge detection circuit 2 after 10 m5ec has elapsed.
3 output P. Referring to K, if POK = rlJ (ink particles are not charged), give one pulse of Po1C to the phase setting circuit 24 to shift the phase of the excitation reference pulse V by one step, and also set a 10 m5ec timer. and wait for timeout, then P again.
See OK. Mo and P. If K=rlJ, PDK
is applied to the one-pulse circuit 24. Similarly, pOK
When = rOJ, step■ To adjust the deflection amount below'
Move. P even after giving 8 pulses of pDK. If K = rOJ, set the Tpdt timer and
Wait for the elapse of d+, and when the time elapses, return to the phase search in step (2).

In adjusting the amount of deflection, the unit 25 first sends S to the circuit 20.
Set the output of the maximum charging voltage code printed on CC"", then set the output of DGc=, r, OJ, turn on the AND gate AN3 of the circuit 20 (gate open), turn off AN4 (gate open), and turn on SW. is closed to the circuit 20 side, and 10
Set the m5ec timer. As a result, in the circuit 20, the AND gate AN3 generates the pulse C1 with a CP distribution pattern of 360 μs per period, in which the eight printing charge timing pulses CP are OR-gal "0" for 160 μsec. AND GATE GROUP AN G & L THIS C
It conducts in a P distribution pattern and applies a charging voltage code Scc to the D/A converter DAI. Ink particles are continuous 16
1':) out of 1' (160 μs), 8 are charged, and the next 16 (160 μs) are uncharged.
This becomes a charging pattern with one period of μs. Note that during phase search, a charging voltage (corresponding to p) is applied to charge 16 consecutive ink particles, but when adjusting the deflection amount, a charging voltage synchronized with pulse C1 is applied, and C
1 is a given frequency of PP, and the ink droplets are pulsed P,
Please note that one item is generated for each item. In this way, even when adjusting the amount of deflection, charging is performed using a charging pattern in which one period is 320 μs.

Next, referring also to FIG. 8b, when the 10m5ec timer times out, the printing control unit 25 detects the output P of the charge detection circuit 23. If PoK is "0", first set the output gain code to the pump energizing circuit 16 to 0.
The count increases by 0, and the count of the number of times increases by 1,
PoK-When it is "1", the output gain code is G.

, the number counter is incremented by 1, and an output code S to the circuit 20 is sent to the circuit 20 to stop charging the ink particles.
. C is cleared, the TPd2 timer is set, and the timer waits for the time to elapse before returning to the phase search in step °■ of FIG. 8a. Tpd2 has an output gain code GCo of 10G. After closing, the result is GCC 10G. This is the time it takes for the corresponding ink pressure to appear at the eighth nozzle of the head and stabilize. The reason for returning to the phase search is to reset the appropriate phase for the changed ink pressure, since the appropriate charging phase (in this embodiment, the excitation voltage phase) is shifted due to a change in the ink pressure.

When the phase search setting is completed, return to the deflection amount adjustment in step ①, and P after 10 m5ec in the same manner as above. See K. This time, the content of the number counter is 1, so
When Po1c=rlJ, the output gain code Gcc is set to 17. (,.take down,P
When oK is "0", the output gain code CCC is set to la in step 2 of FIG. 8b. , and return to the phase search in step ① in the same way as described above. When the content of the number of times is 2, step ■ in FIG. 8b is executed.

Output gain code G as shown in ■. C is soil ζG. change. In this embodiment, G0=8, so IG.

-2, the next star G. is 1 (minimum change unit). So, when the content of the number karanta is 3 (Sat G).

±Spoon G. :I:ToG. ), P
When oK=0, the output gain code is increased by ζGo in step 2 of FIG. 8b in order to cause the ink particles to come off the upper end of the electrode 13. If PoK="1", the convergence flag is set in step (2) of FIG. 8b, and the output gain code is decreased by the minimum unit.

If the content of the number of times register is 4 or more, PoK2'
0", if the convergence flag is set, P
. K-[Moon, so that the ink particles that had missed the upper end of the electrode 13 collide with the electrode 13 due to the previous minimum unit amount gain change (it is assumed that it has become 2), so So, =
OID Go=rlJ, the number counter and convergence flag are cleared, and a signal indicating recording ready is output to the printer central control bit (deflection amount adjustment completed). If the convergence flag is not set, it is assumed that the charged ink particles are colliding with the electrode 13 as before, and step 0 in FIG. 8b is performed.
to decrease the gain by the minimum unit amount. Pox"41J, the convergence flag is referred to in step [phase] of FIG. 8b, and if it is set, the process proceeds to step 0; if it is not set, the convergence flag is set and the process proceeds to step 0.Contents of the number of times counter When is 7 or more, it is usually G. -8 is ±G.

+37. a. +'4a. Within six gain changes of SAT'4G and -1-1, the charged ink particles come to collide with the electrode 13 from a trajectory that deviates from the upper end of the electrode 13 by the minimum unit amount of the gain code. , 7 or more, it is assumed that there is an abnormality, and an abnormality signal is output to the printer central control unit, Soo is cleared to stop charging, the number counter and convergence flag are cleared, and the output gain code is set to G. C
returns to the standard gain code and waits for a command to arrive from the printer central control unit. When a recording command is received from the printer central control unit, the process returns to the main routine and the recording control flow returns to step 2.

In the above embodiment, the standard gain code is first set to DA2, then G. , Spoon G. , /4Go, to focus the charged ink particles on the upper end of the electrode 13, and finally, first remove the charged ink particles from the upper end of the electrode 13, and then lower the output gain code in minimum units. The charged ink particles are brought close to the electrode 13, and when the charged ink particles collide with the electrode 13, the gain adjustment is terminated. The gain adjustment may be completed when the code is raised and charged ink particles no longer collide with the electrode 13. In any case, by changing each field, the charged ink particles converge quickly on a specific trajectory, and when the gain adjustment is finished, there is a one-to-one correspondence between the printed charge maximum level code and the ink particle deflection trajectory. .

ゝ1 In the phase search and deflection amount adjustment explained above,
The gutter 1 is caused by ink splashes and mist that collide with the electrode 13.
Even if the inner wall of 2 becomes dirty and the insulation between the electrode 13 and the ground decreases, the insulation resistance when it is not dirty is more than IM, Ω, and even when it is dirty, it is about 100Ω to IMΩ. Therefore, by setting the resistance value of the resistor R to 10KΩ or less, and by periodically repeating the pattern of charged ink particles and uncharged ink particles as described above, pulsations with a period longer than the ink particle generation period can be detected. By applying this to the circuit, stable deflection detection is performed without being affected by the DC noise level. During the recording operation, ink does not fly to the gutter 12, so the drop in insulation resistance of the gutter 12 is small, and even during phase search, uncharged ink particles are captured by the gutter 11, so only charged ink particles head toward the gutter 12. Moreover, since the phase search ends when this charge is detected, and furthermore, the ink is not charged until the ink pressure is stabilized, the insulation of the electrode 13 decreases little during the phase search and deflection amount adjustment.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of the main parts of the mechanism of an embodiment of the present invention, and FIG. 2 is a block diagram showing the main electrical elements. Figure 3 is a circuit diagram showing the configuration of the charge detection path 23 shown in Figure 2, Figure 4 is a circuit diagram showing the configuration of the phase setting circuit and path shown in Figure 2, and Figure 5 is a phase setting circuit. 6 is a circuit diagram showing the configuration of the printing charge voltage generation circuit 20 shown in FIG. 2, and FIG. 7 is a circuit diagram showing the configuration of the pump energizing circuit 16 shown in FIG. 2. The circuit diagrams shown in FIGS. 8a and 8b are flowcharts showing the deflection amount adjustment control of the printing control unit 25 shown in FIG. 2.6: Filter 5: Solenoid valve 8: Ink jet head 9: Charging electrode 10, . 102
: Deflection electrode・ 11.12 Nigator 13: Board charge detection electrode 14: Shield wire 16: Pump energizing circuit (ink pressure setting means) 26: Recording paper R: Resistor (resistance means) 20: Impression charge voltage generation Vessel (@ direction search II
cjE generation means) Patent applicant Ricoh Co., Ltd. -M

Claims (5)

[Claims] (1) Pressurized ink is supplied to the ink jetting port, vibration is applied to the ink jetted from the ink jetting port, and the ink jetted from the ink jetting port is regularly separated into ink particles. In a deflection control inkjet recording device that generates charged ink particles by applying a charging electric field and deflecting the charged ink particles by a deflection electric field, a plate-shaped charge detection electrode with one end adjacent to a predetermined deflection locus; resistance means for connecting the plate-like charge detection electrode to a predetermined potential point; charge detection connected to the plate-like charge detection electrode for detecting discharge of charged ink particles colliding with the plate-like charge detection electrode passing through the resistance means; circuit; deflection search voltage generating means for generating a charging voltage that switches between a charged level and a non-charged level at a predetermined cycle longer than the ink droplet generation cycle; and ink pressure setting means; A deflection control inkjet recording device configured to change a set value of an ink pressure setting means by using a deflection control inkjet recording device. (2) The charge detection circuit is configured by a high input impedance field effect transistor, an amplifier, a bypass filter, an integrating circuit, and a comparator.
Deflection control inkjet recording device as described in 2. (3) The resistance means is a resistor.
The deflection control inkjet recording device according to item 1) or item (2). (4) The deflection control inkjet recording apparatus according to claim 1, wherein the ink pressure setting means is a pump energizing circuit for pressurizing the ink. (5) The deflection control inkjet recording apparatus according to claim (4), wherein the energizing circuit is a pump energizing voltage generator with adjustable gain.