JPH05229126A - Continuously jetting ink jet recorder - Google Patents

Abstract

PURPOSE:To detect a position of an ink jet shaft (nozzle shaft) in a simple and easy manner with high accuracy. CONSTITUTION:Ink jetted out of a nozzle 1 is divided into a series of ink particle trains. A control electrode 3 electrifies the ink particles by a dc test voltage, which is about one-half of a control voltage at the time of recording and applied from a dc power source DCS. A deflecting electrode 7 forms a deflection electric field orthogonal to an ink jet shaft to deflect the electrified ink particles as well as electrifies the ink particles splashed by the collision with the tip end of a knife edge 5 to a reversed polarity. A conductive particle catcher 8 catches the ink particles which have not been cut by the knife edge 5. An electric current/voltage conversion circuit CD detects the electric charge on the caught ink particles. Based on the detected electric charges, a polarity discrimination circuit PD judges whether the ink jet shaft is ideally adjusted. Based on the judged result, the ink jet shaft (nozzle shaft) is adjusted by an adjusting screw 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a continuous jet type ink jet recording apparatus, and more particularly to adjustment of an ink jet shaft (nozzle axis) in the continuous jet type ink jet recording apparatus.

[0002]

2. Description of the Related Art In a conventional continuous jet type ink jet recording apparatus, for example, as shown in FIG. 11, an ink bottle 91 for containing ink, an ink pump 92 for pressurizing and delivering the ink, and an ink tube 93 for supplying the ink. When,
Nozzle 94 having a very small diameter circular orifice, and nozzle 9
Ink electrode 95 for setting the potential of the ink in 4 to the ground level
And a vibrator 96 formed of a piezo vibrator attached to the nozzle 94, a vibrator driving oscillator 97 for giving an excitation signal to the vibrator 96, and a circular opening or a slit-like opening concentric with the nozzle 94. A control electrode 98 to which a control signal for controlling the charging of the inkjet corresponding to the image signal is applied.
And a ground electrode 99 which is grounded in front of the control electrode 98 and a knife edge 10 attached to the ground electrode 99.
0, a deflection high-voltage DC power supply (hereinafter, simply referred to as a deflection power supply) 101, and the deflection power supply 101 are connected to the ground electrode 99.
And a deflection electrode 102 for deflecting the charged ink particles to the ground electrode 99 side by creating a strong electric field orthogonal to the inkjet axis. In FIG. 11, reference numeral 103 indicates a rotary drum around which the recording medium is wound.

In such a conventional continuous jet type ink jet recording apparatus, the ink pressurized by the ink pump 92 is guided to the nozzle 94 through the ink tube 93, the ink jet is formed from the orifice, the ink jet diameter, the flow velocity and the ink physical properties. It splits into a series of ink particles at a spontaneous particle formation frequency that depends on the value. At this time, the nozzle 94
If the excitation frequency of the vibrator 96 attached to the vibrator is set near the spontaneous particle formation frequency, the particle formation is synchronized with the excitation of the vibrator 96, and extremely uniform size ink particles are generated in accordance with the excitation frequency.

When this uniform ink particle array is subjected to binary charge modulation by a control signal (recording pulse) whose phase is synchronized with the excitation signal, the charged ink particles are deflected to the ground electrode 99 side by the action of the deflection electric field. The non-charged ink particles cut by the knife edge 100 travel straight on the knife edge 100 to record dots on the recording medium wound around the rotating drum 103. Therefore, if the control signal (recording pulse) is made to correspond to the print signal or the image signal, the character or the image is binaryly recorded on the recording medium.

In order to properly and stably control the on / off of recording by a control signal given to the control electrode 98, a sufficient deflection amount is given to the ink jet and the position of the ink jet axis (nozzle axis) and the knife edge 100. It is necessary to set the relationship optimally.

Regarding the deflection amount of the ink jet, in the conventional continuous jet type ink jet recording apparatus which has been put into practical use, the ink jet is charged and modulated at 40 to 150 V,
Deflection of 0.1 to 0.4 mm on the knife edge 100
Is designed to be.

Regarding the adjustment of the ink jet shaft (nozzle shaft), in the conventional continuous jet type ink jet recording apparatus which has been put into practical use, for example, as shown in FIG. The structure is such that it is biased and can be independently adjusted at the fulcrum 111 by the adjusting screw 113, and is mechanically adjusted manually.

The deflection amount of the ink jet is proportional to the control voltage. Therefore, the optimum position for adjusting the inkjet shaft (nozzle shaft) is optimum when the tip of the knife edge 100 is substantially at the half point of the inkjet shaft when the control voltage is on and when the control voltage is off. However, in an actual machine, it is almost impossible to adjust the inkjet axis (nozzle axis) by observing the inkjet axis with a microscope.

Therefore, actually, the position of the nozzle 94 is adjusted by operating the continuous jet type ink jet recording apparatus and manually operating the adjusting screw 113 while performing the test printing.

On the other hand, when the relative position between the inkjet and the garter member (corresponding to the knife edge) is set and adjusted, the deflection amount of the substantial deflection electric field in the inkjet is reduced from the normal recording (for example, to 1/2). A continuous-jet type ink jet recording apparatus which has been proposed has been already proposed (see Japanese Laid-Open Patent Publication No. 2-1322). In this continuous jet type ink jet recording apparatus, by further connecting a charge amount detector to the garter member and monitoring the output thereof, it is possible to easily determine whether or not ink particles have hit the garter member.

In the description of FIG. 11, the charged ink particles are deflected and removed to the ground electrode 99 side, and the non-charged ink particles are moved straight on the knife edge 100 to be used for recording, but the reverse case is also possible. .. That is, the non-charged straight ink particles are cut by the knife edge 100 and the ink particles used for recording are attracted to the deflection electrode 102 (in the case of FIG. 11, positive polarity, that is, a negative control signal is given to the control electrode 98). It is a method of recording with charged ink particles by charging the ink to a sheet, passing through the knife edge 100.

[0012]

In the conventional continuous jet type ink jet recording apparatus described above, the adjusting screw 113 is manually operated while actually operating the continuous jet type ink jet recording apparatus to perform test printing. Since the position of the (axis) was adjusted, the adjustment was qualitative and there was a problem that it was impossible to confirm the two-minute point. That is, since it is possible to know the moment when the ink jet collides with the knife edge 100 in the adjustment process, the position of the nozzle 94 is estimated by the rotation angle of the adjustment screw 113 on the basis of that position, which is the limit that can be implemented. Backlash makes it even more inaccurate).

Further, since the position of the nozzle 94 is adjusted by manually operating the adjusting screw 113 while actually operating the continuous jet type ink jet recording apparatus, there is a problem that mechanical and electrical dangers are involved.

Further, since the recording medium is consumed for adjusting the position of the nozzle 94, there is a problem that it is uneconomical.

Further, when the ink jet collides with the tip of the knife edge 100 in the recording area, there is a problem that the rotary drum 103 and the like are contaminated by mist.

On the other hand, in the conventional continuous jet type ink jet recording apparatus, when the relative position between the ink jet and the garter member is set and adjusted, a substantial deflection electric field deflection amount in the ink jet is set to be smaller than that in the normal recording. Since the amount of deflection at the time of adjustment is only one, it is not possible to confirm how accurately the adjustment has been made. Precise adjustment is impossible unless the mechanical precision is high. When the mechanical precision is increased There is a problem that the continuous jet type ink jet recording apparatus becomes expensive. In particular, when the charge amount detector is connected to the garter member, the garter member must have an insulating structure. However, since the garter member is a portion that is always exposed to ink, it is very difficult to obtain an insulating structure. There is a problem that it is difficult and the structure is complicated.

In view of the above-mentioned point, the inventor of the present application performs a test run of the ink jet in a state where the rotary drum and the carriage are stopped in an area unrelated to recording (hereinafter referred to as home position), and when the ink jet is on and off. A continuous jet type ink jet in which the position of the ink jet axis (nozzle axis) is detected by giving a slight deflection around the bifurcation point of and and detecting the electric charge (current) carried by the ink jet that has passed through the knife edge. A recording device has already been proposed in Japanese Patent Application No. 2-275830.

Further, the inventor of the present application performs a test run of the ink jet in a state where the rotary drum and the carriage are stopped at the home position, gives the ink jet a continuously changing deflection (including stepwise), and passes the knife edge. Japanese Patent Application No. 2-299203 has already proposed a continuous jet type inkjet recording apparatus in which the position of the inkjet shaft (nozzle shaft) is detected by detecting the electric charge (current) carried by the inkjet.

It is an object of the present invention to provide a continuous jet type ink jet recording apparatus which is further improved to detect the position of the ink jet shaft (nozzle shaft) easily and accurately. That is, while the rotary drum and the carriage are stopped at the home position, a constant positive (or negative) charge is applied to the ink jet to perform a test run, and ink that collides with the knife edge and scatters is negatively (or negatively) induced by the deflection electric field. It is an object of the present invention to provide a continuous jet type ink jet recording apparatus in which the position of the ink jet shaft (nozzle shaft) is detected by detecting the charge that is positively charged.

[0020]

A continuous jet type ink jet recording apparatus of the present invention comprises a particle forming means for dividing an ink jet into a series of ink particle rows, and an ink particle formed by the particle forming means for charging. 1 charging means, a deflecting means for deflecting charged ink particles by creating a deflection electric field orthogonal to the inkjet axis, and a separating means for cutting ink particles deflected by the deflecting means and passing undeflected ink particles, The second charging means for charging the ink particles that collide with the tip of the separating means and scatter, and the ink particles that have passed through the separating means and the ink particles that collide with the tip of the separating means and scatter to capture the charge. Based on the electric charge detection means for detecting and the electric charge detected by the electric charge detection means, it is determined whether or not the adjustment state of the inkjet shaft is possible. That includes a jet axis adjusting state determining means, and a jet axis adjusting means for adjusting the positional relationship between the separating means and the ink jet axis.

[0021]

In the continuous jet type ink jet recording apparatus of the present invention, the particle forming means divides the ink jet into a series of ink particle rows, and the first charging means charges and deflects the ink particles formed by the particle forming means. The means creates a deflection electric field orthogonal to the inkjet axis to deflect the charged ink particles, the separating means cuts the ink particles deflected by the deflecting means and allows the undeflected ink particles to pass, and the second charging means separates the separating means. The ink particles that collide with the tip of the ink and are scattered are charged, and the charge detecting means captures the ink particles that have passed through the separating means and the ink particles that have scattered and collide with the tip of the separating means, and detects the charge, and the ink jet axis adjustment state. The determination means determines whether the adjustment state of the inkjet shaft is possible based on the charges detected by the charge detection means,
The inkjet axis adjusting means adjusts the positional relationship between the inkjet axis and the separating means.

[0022]

The present invention will be described in detail with reference to the drawings.

FIG. 1 is a block diagram showing the essential parts of a continuous jet type ink jet recording apparatus according to the first embodiment of the present invention. The continuous jet type inkjet recording apparatus of the present embodiment is
A non-charged ink particle is used for recording to cut off the charged ink particle, a nozzle 1 having an extremely small diameter circular orifice, and an ink electrode 2 for setting the potential of the ink in the nozzle 1 to the ground level. A control electrode 3 having a circular opening or a slit-shaped opening that is concentric with the nozzle 1 and to which a control signal for controlling charging of the inkjet is applied; and a ground electrode 4 that is grounded in front of the control electrode 3. A conductive knife edge 5 mounted on the ground electrode 4, a deflection power source 6, and a deflection power source 6 are connected to form a strong electric field orthogonal to the inkjet axis between the ground electrode 4 and charged ink particles to the ground electrode 4 side. A deflecting electrode 7 for deflecting the light to a negative electrode, a conductive particle catcher 8 serving as a detection electrode arranged at a home position in front of the ground electrode 4 and the deflecting electrode 7, and a conductive particle catcher. A shield wire 9 connected to the compression spring 12 for biasing the fulcrum 11 of the nozzle 1, the nozzle 1
An adjusting screw 13 for adjusting the position of the nozzle 1 (inclination of the nozzle axis), a positive DC power supply DCS whose output is applied to the control electrode 3 when adjusting the inkjet axis, and a microprocessor (control means). MPU: not shown)
A switch SW1 for connecting either the control signal or the output of the DC power supply DCS to the control electrode 3 based on an instruction from
And the current / voltage conversion circuit CD connected to the shielded wire 9
And a polarity determination circuit PD that determines the polarity of the output V ₀ of the current / voltage conversion circuit CD. The output of the polarity determination circuit PD is processed by the MPU and displayed on a display device (not shown). The DC power supply DCS is composed of a variable DC power supply whose output voltage can be adjusted.

Next, the operation of the continuous jet type ink jet recording apparatus of the first embodiment thus constructed will be described.

When adjusting the ink jet shaft (nozzle shaft), a rotary drum (not shown) around which the recording medium is wound.
And the carriage (not shown) on which the nozzle 1 is mounted is set to the home position and stopped.

Next, ink is supplied to an ink pump (not shown).
And is guided to the nozzle 1 through an ink tube (not shown), and the inkjet is ejected from the nozzle 1 to be held in a steady state. Further, a vibrator (not shown) attached to the nozzle 1 is excited at an oscillation frequency near the spontaneous particle generation frequency of the inkjet, and the inkjet ejected from the nozzle 1 becomes particles in synchronization with the excitation of the oscillator. ..

From this state, the MPU as the control means
First, the switch SW1 is switched to connect the positive polarity DC power supply DCS to the control electrode 3. During recording, the switch SW1 is switched to connect the control signal (recording image signal) to the control electrode 3. The DC test voltage output from the DC power supply DCS is set to a value around ½ of the control signal voltage (voltage for charging (turning off) the inkjet during recording).

In this state, when the ink jet shaft (nozzle shaft) is adjusted up and down by the adjusting screw 13, the ink jet passes through the knife edge 5, is cut by the knife edge 5, collides with the knife edge 5, and scatters. The current / voltage conversion circuit CD is generated depending on whether the formed ink is captured by the conductive particle catcher 8.
Electric charge (charge carried by inkjet)
The polarity of changes from negative, 0 (no charge), and positive. Therefore, the output of the polarity determination circuit PD also changes accordingly, and the output can determine the position of the inkjet shaft. Below, the reason is shown in FIG.
A description will be given based on (b) and (c).

2 (a), 2 (b) and 2 (c) show the state where the ink jet passes over the knife edge 5, the state where it is cut by the knife edge 5, and the collision with the tip of the knife edge 5, respectively. And shows the scattered state.
When passing over the knife edge 5 shown in FIG. 2A, the DC power source DC having the positive polarity applied to the control electrode 3
Since the negatively charged inkjet is captured by the conductive particle catcher 8 by the induction of the DC test voltage from S, the negative charge flows into the current / voltage conversion circuit CD. Figure 2
When it is cut by the knife edge 5 shown in (b), it is 0, that is, there is no charge inflow. When the tip of the knife edge 5 shown in FIG. 2 (c) collides and scatters, the knife edge 5 is grounded, and the negative charge of the ink jet disappears due to the collision. Then, when scattered from there, it is induced from the negatively charged deflection electrode 7 via the capacitor C _S, and droplets having a positive charge are generated. When this is captured by the conductive particle catcher 8, positive charges flow into the current / voltage conversion circuit CD.

Therefore, the position of the ink jet shaft can be determined by monitoring the polarity of this charge, that is, the output of the polarity determination circuit PD.

The optimum position of the inkjet shaft is the position where the positive charge is detected. That is, at this time, as described above, the ink jet charged with the DC test voltage around ½ of the control voltage at the time of recording and deflected by the deflection electric field to about ½ at the time of recording has the tip of the knife edge 5 moved. You're humbled. Therefore, since the deflection amount is proportional to the control voltage, the tip of the knife edge 5 is located at the bisector of the straight jet (ON) and the deflection jet (OFF) during recording.

At the time of recording, whether the tip of the knife edge 5 is exactly at the bisector of the straight jet and the deflecting jet is determined by the image quality of the recorded image. According to the present embodiment, the tip position of the knife edge 5 is set to an arbitrary position between the straight jet and the deflecting jet by changing the DC test voltage of the DC power supply DCS in the range of 0 to the control voltage during recording. Can be set.

By the way, in the continuous jet type ink jet recording apparatus of the first embodiment, the current / voltage conversion circuit CD must be capable of measuring a very small jet current of about 10 nA or less.

FIG. 3 is a circuit diagram showing an example of a circuit system suitable for use as the current / voltage converting circuit CD and the synchronizing signal generating circuit in the continuous jet type ink jet recording apparatus of the first embodiment shown in FIG. is there.

The current / voltage conversion circuit CD has an integrating capacitor C and an input stage of an FET (Field Effect).
Transistor) operational amplifier OP1
And an integrator using a commercial AC power supply of 100 V (hereinafter AC
FE operating in synchronization with a frequency of 100 V)
It is composed of three switches SW2, SW3, and SW4 that are T.

Further, the synchronizing signal generating circuit is a transformer T
And a resistor R, diodes D1 and D2, a Schmitt gate SG, a preset counter PSC, delay type flip-flops FF1 and FF2, an inverter IN, and an AND gate AD.

The preset value of the preset counter PSC can be set variably (the path is not shown), so that the integration time can be varied by an integral multiple of the cycle of AC100V. If the integration time is lengthened, the S / N ratio naturally improves. In this embodiment, as shown in the timing chart of FIG. 4, the integration time is set to three times the cycle of AC100V.

Reset signal RESET, integration start signal H
The OLD ^* (the superscript * indicates an inverted signal. The same applies to the following) and the integration end signal HOLD are fixed to one cycle of AC100V, respectively, and the switches SW4, SW3, and SW2 are closed at the "H" level. West,
Open at "L" level. The sample hold signal S / H is output in synchronization with the latter half of the hold period when the integration end signal HOLD is at "H" level.

In the synchronizing signal generation circuit, AC100V is stepped down by the transformer T, clamped to 0V and 5V by the diodes D1 and D2, and AC10 is applied by the Schmitt gate SG.
TTL (Transistor-Tra) synchronized with 0V
clock signal C of the nsistor logic level
Make K. Next, based on this clock signal CK, a preset counter PSC and two flip-flops FF
1 and FF2, inverter IN and AND gate AD, the integration start signal HOLD shown in the timing chart
^* , An integration end signal HOLD, a reset signal RESET and a sample hold signal S / H are created.

When the reset signal RESET becomes "H", the switch SW4 is closed, the integrating capacitor C is short-circuited, and the output voltage V ₀ of the integrator is reset to 0V.

After one cycle of AC100V, the reset signal R
When ESET becomes "L", the switch SW4 is opened. At this time, since the integration end signal HOLD is “L” (switch SW2 is open) and the integration start signal HOLD ^* is “H” (switch SW3 is closed), the jet current I _j is the operational amplifier OP1 forming the integrator. Flows into the virtual ground point of and integration is started.

Since the ink jet is charged so as to have a negative charge by the control signal applied to the control electrode 3,
A current I _{j in the} direction of the arrow flows through the integrating capacitor C, and the output voltage V ₀ of the integrator becomes a positive voltage.

When an integral multiple (three times in the figure) of the AC100V cycle has elapsed from the start of integration, the integration end signal HO
LD is "H" (switch SW2 is closed), integration start signal H
OLD ^* becomes the "L" (the switch SW3 is opened), the jet current I _j is cut off, so far into the integrating capacitor C jets are integrated into a current I _j is the output voltage V of integrator
Holds as ₀ .

By the way, in an actual machine, it is almost impossible to completely shield the space between the conductive particle catcher 8 and the integrator from noise. Therefore, during the integration operation, AC100V noise and high-frequency noise generated from other peripheral electronic devices are superimposed on the output. Of these, the high frequency noise is sufficiently long that the integration time is one cycle of 100 VAC or more, and is averaged so that no problem occurs. Further, in the current / voltage conversion circuit CD of this example, the integration time of the jet current I _{j is set to} an integral multiple of the cycle of AC100V, so that the noise of AC100V is averaged during the integration period and automatically removed. It will be.

Further, when the integration of the jet current I _j is completed, the integration start signal HOLD ^* becomes “L” and the switch SW3 is opened, so that the jet current I _j is turned off and at the same time the integrator is fed from the input side. The incoming noise is also blocked. Therefore, the operation of the polarity discriminating circuit PD is performed at this timing (in the section where the sample hold signal S / H is "H" in FIG. 4).
, The output of the integrator is free of noise and the jet current I _j is read correctly. Therefore, if only the integrator is sufficiently shielded, the noise is only the noise generated inside, and the jet current I _j can be measured with extremely high accuracy. In this way, extremely high performance current detecting means can be constructed with simple and inexpensive elements.

Now, the jet current I _j (Amper
e), the integration capacitor capacity C (Farad), and the integration time T (sec), the output V ₀ (Vo of the integrator OP1
lt) is V ₀ = I _j T / C. For example, I _j = 1
When 0 ^-9 A (1 nA), C = 10 ^-9 F (1000 p
F) and T = 0.1 sec (AC100V 5 cycles), V ₀ = 0.1V (100 mV), which is a sufficiently practical circuit.

FIG. 5A is a circuit diagram showing an example of a polarity discriminating circuit PD suitable for use in the continuous jet type ink jet recording apparatus of the first embodiment. This polarity discrimination circuit PD
Are two comparators CP1 and CP2 and two resistors R
1 and R2, a negative reference power source −V _S, and a positive reference power source + V _S. Where negative reference power supply −
V _S is larger than the voltage output from the current / voltage conversion circuit CD when the ink jet passes over the knife edge 5, and the positive reference power source + V _S causes the ink jet to collide with the tip of the knife edge 5 and splash the droplets. It is set to be smaller than the output voltage of the current / voltage conversion circuit CD due to the electric charges.

Two comparators CP1 and CP2 are also provided.
All operate with the sample hold signal S / H as a strobe signal. Resistors R1 and R2 convert the outputs of comparators CP1 and CP2 to logic levels.
2-bit output voltage V from the comparators CP1 and CP2
_{From 1} and V ₂ , as shown in the table of FIG. 5B, three positions of the inkjet shaft, that is, a state in which the inkjet passes over the knife edge 5 (V _O <−V _S ),
Inkjet to a state in which it is cut by the knife-edge _{5 (-V S <V O =} 0 <+ V S), the ink jet state impinging on the tip of the knife edge _{5 (V O> + V S} ) and can be discriminated.

FIG. 6 is a circuit diagram showing another example of the polarity discriminating circuit PD suitable for use in the continuous jet type ink jet recording apparatus of the first embodiment. This polarity determination circuit PD is
Operational amplifier OP2, bias power supply _Vb , four resistors R3, R4, R5 and R6, and two diodes D3.
And D4, and an A / D that operates in synchronization with the sample-hold signal S / H.
It is composed of a converter ADC. Current / voltage conversion circuit C
The output voltage V _{0 of} D is level-shifted by the non-inverting amplifier (when the inkjet is cut at the knife edge 5 (V
₀ = 0) so that the output becomes a positive voltage capable of A / D conversion) and amplification to a level at which A / D conversion is possible. The level shift is performed by the bias power supply V _b and the resistor R5, and the amplification of the output voltage V ₀ is performed by the resistors R3 and R4. Diode D3, resistor R6 and diode D4
Is an element for clamping the output of the non-inverting amplifier to 0 and a voltage that does not destroy the A / D converter ADC. When this polarity discriminating circuit PD is used, the state of the inkjet shaft is output as the difference between the output data of the A / D converter ADC.

In the continuous jet type ink jet recording apparatus of the first embodiment, the case where the ink particles are negatively charged and the negative deflection electric field is used has been described. However, even if the ink particles are positively charged and the positive deflection electric field is used, it is exactly the same. The effect of is obtained. However, in that case, the output voltage V _{0 of the} current / voltage conversion circuit CD
The polarity and the state of the inkjet shaft have an inverse relationship.

Further, in the continuous jet type ink jet recording apparatus of the first embodiment, the case where the DC power source DCS and the switch SW1 are used at the time of adjusting the ink jet axis is explained, but in the control signal generator (not shown). It is also possible to control this with the built-in MPU.

FIG. 7 is a view showing the arrangement of a continuous jet type ink jet recording apparatus according to the second embodiment of the present invention. The continuous jet type ink jet recording apparatus of the present embodiment uses charged ink particles for recording and cuts non-charged ink particles. The continuous jet type ink jet recording apparatus of the first embodiment shown in FIG. A device is a DC power supply DC
The DC test voltage output from S'is negative and is set to a value around 1/2 of the control signal voltage (the voltage that charges (turns on) the inkjet during recording), the position of the inkjet shaft and the charging of the inkjet. The state (explained in FIG. 8), the current / voltage conversion circuit CD ′ (explained in FIG. 9), and the A / D converter ADC ′ (explained in FIG. 10) are different.

8 (a), 8 (b) and 8 (c) show the state where the ink jet is passing over the knife edge 5, the state where it is cut by the knife edge 5 and the collision with the tip of the knife edge 5, respectively. And shows the scattered state.
When passing over the knife edge 5 shown in FIG. 8A, the DC power source DC of the negative polarity applied to the control electrode 3 is applied.
The positively charged ink jet is captured by the conductive particle catcher 8 due to the induction of the DC test voltage from S ′, so that the positive charge flows into the current / voltage conversion circuit CD ′. When cut by the knife edge 5 shown in FIG. 8B, 0, that is, there is no charge inflow. When the knife edge 5 shown in FIG. 8C collides with the tip of the knife edge 5 and scatters, since the knife edge 5 is grounded, the positive charge of the ink jet disappears due to the collision. When scattered from there, it is induced from the negatively charged deflection electrode 7 via the capacitance C _S , and again droplets having a positive charge are generated. However, in this case, since the deflection voltage is 10 times or more of the DC test voltage, it is extremely strongly charged, and when it is captured by the conductive particle catcher 8, it has the same polarity as that shown in FIG. Positive charge of the current flows into the current / voltage conversion circuit CD ′.

Therefore, the position of the ink jet shaft can be determined by monitoring the presence / absence of positive charge and the size thereof.

The optimum position of the inkjet shaft is the position where a large positive charge is detected. That is, at this time,
As described above, it is charged with a DC test voltage near ½ of the control voltage at the time of recording, and about 1 / the time of recording at the deflection electric field.
The inkjet that has been deflected by 2 makes the tip of the knife edge 5 graze. Therefore, since the deflection amount is proportional to the control voltage, the tip of the knife edge 5 is located at the bisector of the straight jet (OFF) and the deflection jet (ON) during recording.

At the time of recording, whether the tip of the knife edge 5 is exactly at the bisector of the straight jet and the deflecting jet is determined by the image quality of the recorded image. According to this embodiment, the tip end position of the knife edge 5 is set between the straight jet and the deflecting jet by varying the DC test voltage output from the DC power supply DCS 'within the range of 0 to the control voltage during recording. It can be set at any position.

FIG. 9 is a circuit diagram showing an example of a current / voltage conversion circuit CD 'suitable for use in the continuous jet type ink jet recording apparatus of the second embodiment. In the continuous jet type ink jet recording apparatus of this embodiment, only positive charges of 0 and 2 stages are detected. Therefore, the output of the integrator is
It becomes a negative voltage. Therefore, in the present embodiment, the operational amplifier OP3 is provided in order to enable input to the A / D converter ADC 'in the subsequent stage.
And an output voltage V ₀ is generated through an inverting amplifier composed of two resistors R7 and R8. Amplification factor R8 / R7
Is determined in consideration of the output level of the integrator and the allowable input level of the A / D converter ADC '.

FIG. 10A shows an AD suitable for use in the continuous jet type ink jet recording apparatus of the second embodiment.
It is a circuit diagram which shows an example of converter ADC '. In the continuous jet type ink jet recording apparatus of this embodiment, the same polarity (positive)
It is convenient to use the A / D converter ADC 'for the determination of the position of the inkjet axis, since only the electric charge of is detected. 10A shows an example of a simplified A / D converter composed of two comparators CP3 and CP4, two reference power sources + V _S ^′ , + V _S ^“, and two resistors R9 and R10. , The reference power source + V _S ^' is smaller than the output of the current / voltage conversion circuit CD' when the ink jet passes the knife edge 5, and the reference power source + V _S ^" is the current / jet when the jet collides with the tip of the knife edge 5.
It is set smaller than the output of the voltage conversion circuit CD '.
However, + V _S ^' <+ V _S ^" .

Also, two comparators CP3 and CP4
Both operate using the sample hold signal S / H as a strobe signal. Resistors R9 and R10 convert the outputs of comparators CP3 and CP4 to logic levels. 2-bit output voltage V ₃ from the comparators CP3 and CP4
From V ₄ and V ₄ , as shown in the table of FIG. 10B, three positions of the inkjet shaft, that is, a state in which the inkjet passes the knife edge 5 (+ V _S ^' <V ₀ <+
V _S ^" ), a state where the inkjet is cut by the knife edge 5 (V ₀ <+ V _S ^' ), and a state where the inkjet collides with the tip of the knife edge 5 (V ₀ > + V _S ^" ).
Can be determined.

It is needless to say that a commercially available A / D converter can be used instead of the A / D converter shown in FIG.

In the second embodiment, the case where the ink particles are positively charged and the negative deflection electric field is used has been described. However, the same effect can be obtained even when the ink particles are negatively charged and the positive deflection electric field is used. Be done. However, in that case, current /
The inverting amplifier of the voltage conversion circuit CD 'needs to be a non-inverting amplifier.

In the first and second embodiments, 2
Although the continuous ejection type inkjet recording apparatus of the value control method has been described, it is needless to say that the same can be applied to the continuous ejection type inkjet recording apparatus of the analog deflection method.

[0063]

As described above, according to the present invention,
A state in which the ink particles are deflected to a predetermined position by the DC test voltage and the deflected ink particles pass through the separating means,
Since the state of being cut by the separating means and the state of colliding with the tip of the separating means can be easily detected by the second charging means and the electric charge detecting means, highly accurate and easy adjustment of the inkjet shaft is possible. Has the effect of becoming.

Further, by making the DC test voltage variable, the positional relationship between the ink jet shaft and the separating means can be arbitrarily adjusted.

Further, by configuring the charge detecting means by including an integrator which operates in synchronization with AC100V,
There is an effect that it is possible to detect the inkjet axis with high reliability.

Furthermore, the charging means and the second charging means charge the ink particles to the opposite polarities or the same polarities having greatly different levels, so that the inkjet shaft can be adjusted easily and inexpensively with high accuracy and ease. There is an effect that a continuous jet type ink jet recording apparatus which can be realized can be realized.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a continuous jet type ink jet recording apparatus according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a principle of determining an inkjet shaft in the continuous jet inkjet recording apparatus according to the first embodiment.

3 is a circuit diagram showing an example of a current / voltage conversion circuit in FIG.

FIG. 4 is a timing chart explaining the operation of the current / voltage conversion circuit of FIG.

5 is a circuit diagram showing an example of a polarity determination circuit in FIG.

6 is a circuit diagram showing another example of the polarity determining circuit in FIG.

FIG. 7 is a configuration diagram showing a continuous jet type ink jet recording apparatus according to a second embodiment of the present invention.

FIG. 8 is a diagram illustrating a principle of determining an inkjet shaft in a continuous jet type inkjet recording apparatus according to a second embodiment.

9 is a circuit diagram showing an example of a current / voltage conversion circuit in FIG.

10 is a circuit diagram showing an example of an A / D converter in FIG.

FIG. 11 is a configuration diagram showing an example of a conventional continuous jet type inkjet recording apparatus.

FIG. 12 is a view showing an example of a nozzle adjusting mechanism in FIG.

[Explanation of symbols]

 1 Nozzle 2 Ink Electrode 3 Control Electrode 4 Grounding Electrode 5 Knife Edge 6 Deflection Power Supply 7 Deflection Electrode 8 Conductive Particle Catcher 9 Shield Wire 11 Support Point 12 Compression Spring 13 Adjustment Screw AD and Gate ADC 'A / D Converter C Integration Capacitor CD Current / voltage conversion circuit CP1-CP4 Comparator D1-D4 Diode DCS, DCS 'DC power supply FF1, FF2 Flip-flop IN Inverter OP1-OP3 Operational amplifier PD Polarity determination circuit PSC Preset counter R, R1-R10 Resistance SG Schmitt gate SW1- SW4 switch

Claims (6)

[Claims] 1. A particle forming means for dividing an ink jet into a series of ink particle rows, a first charging means for charging ink particles formed by the particle forming means, and a deflection electric field perpendicular to an ink jet axis. Deflection means for deflecting charged ink particles, separation means for cutting ink particles deflected by this deflection means and passing ink particles not deflected, and ink particles that collide with the tip of this separation means and are scattered Second charging means, charge detection means for capturing the ink particles that have passed through the separation means and ink particles that have collided with the tips of the separation means and scattered, and detect the charge thereof, and the charge detection means detects the charges. An inkjet axis adjustment state determining means for determining whether or not the inkjet axis adjustment state is possible based on an electric charge; Continuous jet type ink jet recording apparatus characterized by comprising a jet axis adjusting means for adjusting the positional relationship between the separating means. 2. The first charging means includes a control signal generating means for generating a control voltage according to a recording signal, a test voltage generating means for generating a DC test voltage between 0 and the control voltage, and an input. A control electrode for charging the ink particles according to the applied voltage, and a switch means for connecting one of the output of the control signal generating means and the output of the test voltage generating means to the control electrode. The continuous jet type ink jet recording apparatus according to claim 1. 3. A control signal generating means for generating a control voltage according to a recording signal and a DC test voltage between 0 and the control voltage, and an output of the control signal generating means. The continuous jet type ink jet recording apparatus according to claim 1, further comprising a control electrode which is connected and charges the ink particles according to an output of the control signal generating means. 4. The continuous jet type ink jet recording apparatus according to claim 1, wherein the second charging unit is included in the deflecting unit. 5. The first charging means and the second charging means charge ink particles to opposite polarities, and the inkjet axis adjustment state determining means is a charge detecting means including a polarity determining means. The continuous jet type inkjet recording apparatus according to claim 1. 6. The first charging means and the second charging means charge ink particles to the same polarity and different levels, and the inkjet axis adjustment state determining means includes an analog / digital converting means. The continuous jet type ink jet recording apparatus according to claim 1, wherein the continuous ejection type ink jet recording apparatus comprises a detecting means.