JP3248809B2 - Continuous jet type inkjet recording device - Google Patents

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 a variable dot size (recording dot diameter) by variably controlling the number of ink particles to be ejected to one pixel, thereby enabling expression of light and shade. The present invention relates to a technology for improving the image quality by accurately controlling the positions of the recording dots regardless of the dot size in the continuous jet type ink jet recording apparatus.

[0002]

2. Description of the Related Art Using a continuous jet type ink jet technology,
A technique for variably controlling the number of ink particles to be applied to one pixel and changing the dot size to express shading is as follows.
For example, US Pat. No. 4,620,196 and JP-A-62-2
No. 25363 and the like.

FIG. 17 is a block diagram showing a conventional rotary drum type continuous jet ink jet recording apparatus. The continuous jet type ink jet recording apparatus includes a nozzle 1 to which a pressurized ink is supplied, an ink electrode 2 for setting the potential of the ink in the nozzle 1 to a ground level, and a piezoelectric vibrator 3 attached to the nozzle 1. , An oscillator OSC for generating a particle-ized frequency signal f _d having a constant particle-ized frequency f _d (hereinafter, the signals are denoted by the same reference numerals as the frequency), and a particle-ized frequency signal f _d from the oscillator OSC. A driver driver CD for amplifying and driving the piezoelectric vibrator 3 to convert the ink jet into particles in synchronism therewith, and a pixel density data D _P having a circular or slit-shaped opening concentric with the nozzle 1
A control electrode 4 to which a charging control signal φ _C for controlling charging of the ink jet is applied, a ground electrode 5 arranged in front of the control electrode 4 and grounded, and a knife edge mounted on the ground electrode 5 6 and a high-voltage DC power supply for deflection (hereinafter, referred to as
A deflection power supply 7 connected to the deflection power supply 7 and a deflection electrode 8 for generating a strong electric field perpendicular to the jet flight axis between the deflection power supply 7 and the ground electrode 5 to deflect the charged ink particles to the ground electrode 5 side.
And a rotary drum DR for generating a charge control signal φ _C
Are read out in synchronization with a line buffer LB that stores pixel density data D _P for one rotation and an encoder clock (pixel recording command signal) f _E from a shaft encoder SE coupled to the axis of the rotating drum DR. Line buffer L
The encoder clock f _E pixel density data D _P from B
And a pulse width modulator PWM that converts the pulse width into a pulse width in synchronization with the particle frequency signal f _d from the oscillator OSC and an output S _C of the pulse width modulator PWM (hereinafter referred to as a PWM signal).
And a high-voltage switch HVS for converting the charge control signal φC into a charge control signal φ _C. In FIG. 17, reference numeral RM indicates a recording medium wound around the rotary drum DR.

[0004] The pulse width modulator PWM converts pixel density data D _P read out from the line buffer LB to the PWM signal S _C having a pulse width corresponding to the value. The pulse width modulator PWM is composed of, for example, a preset down counter. That is, presets the pixel density data D _P with the encoder clock f _E, disintegrating frequency signal f _d
Do it by entering as a down clock, time from the time of the preset to the preset down counter becomes empty is the pulse width of the PWM signal S _C.

FIG. 18 is a view for explaining the principle of variably controlling the dot size by pulse width modulation used in the conventional continuous jet type ink jet recording apparatus shown in FIG. Here, for the sake of convenience, a case where 9 gradations are expressed is shown, and the encoder clock f _E which is the output of the shaft encoder SE has a frequency which is １ ／ of the particleization frequency signal f _d which is the output of the oscillator OSC. is designed so that the phase is locked to the addition disintegrating frequency signal f _d. Eight ink particles in one cycle of the encoder clock f _E form one pixel. Although eight dot size by any number in either the non-charged ink of is controlled, the number of the non-charged ink is stored in the line buffer LB as pixel density data D _P. In FIG.
● represents uncharged ink particles, goes straight without being deflected and is recorded on the recording medium RM, and ○ represents charged ink particles, is deflected and cut by the knife edge 6 and does not reach the recording medium RM. . In particular, FIG. 18 illustrates a case where one pixel is formed of 1, 3, and 5 ink particles.

In such a conventional continuous jet type ink jet recording apparatus, an uncharged ink particle row to be recorded flies in the air and is decelerated by air resistance. FIG. 19 is a diagram illustrating a behavior of an ink particle row constituting a pixel flying in the air. Now, the jet velocity, the particleization frequency f _d
And five jets having the same particle diameter are prepared, and the charge control signal φ _C having 1, 2, 3, 4, and 5 uncharged ink particles per pixel is simultaneously applied to the control electrode 4 (“ A "). When the row of ink particles enters the deflection electrode 8, the charged ink particles begin to be deflected below the jet flight axis by the action of the deflection electric field ("B"). Further, when traveling in the deflection electric field, the uncharged ink particle train on the jet flight axis gradually combines the subsequent ink particles with the head ink particles because the air resistance received by each head ink particle is the largest (“C”). ”). In the combined ink particles, the ratio of the increase of the inertial force (proportional to the cube of the particle size) becomes larger than the increase of the air resistance (proportional to the square of the particle size), and the degree of deceleration due to the air resistance decreases. As a result, when coalescence starts,
When the non-charged ink particle row having a smaller number of ink particles per pixel has a longer delay and reaches the recording medium RM on the rotary drum DR through the knife edge 6, FIG.
A delay as shown in FIG. 9 occurs (“D”). With this delay, smaller dots (dots with lower pixel density) are printed with a delay in the direction opposite to the rotation direction (main scanning direction) of the rotating drum DR, resulting in a positional shift of the recorded dots according to the dot size. .

[0007] To solve this problem, the present inventor has (have larger dots as the delay time is increased) charge control signal phi _C applied timing is delayed in response to the dot size, position shift of the recording dots Has already proposed a continuous ejection type ink jet recording apparatus that corrects the image quality.
-246034). As a result, this problem has been solved, but a new problem has occurred in that the recording time is lengthened. That is, in the continuous jet type ink jet recording apparatus, the larger the dot size (the larger the number of non-charged ink particles), the longer the delay time must be. It must be included in the number of ink particles per pixel. As a result, the number of ink particles per pixel increases, resulting in an increase in running cost due to useless ink and an increase in recording time.

[0008]

In the above-described conventional continuous jet type ink jet recording apparatus, since the delay of the non-charged ink particle row differs depending on the dot size, the position of the recording dot is shifted. The resulting image has a problem that the position shift is noticeable in a place where the density changes rapidly. In particular, there is a problem that when a color image in which colors having greatly different ratios of C (cyan), M (magenta), and Y (yellow) are expressed, a significant color shift occurs.

[0009] In order to solve this problem, the charge control signal in the continuous jet type ink jet recording apparatus for delaying the application timing of phi _C, lengthening the running cost increase the recording time by a waste ink depending on the dot size There is a problem that occurs.

In view of the foregoing, it is an object of the present invention to correct a delay of an uncharged ink particle row depending on a dot size,
It is an object of the present invention to provide a continuous ejection type ink jet recording apparatus in which recording dots are recorded at predetermined dot positions regardless of the dot size. Specifically, a correction charge according to the dot size is given to the ink particles to be recorded (hereinafter, referred to as recording ink particles), and the jet flight axis is displaced to the deflection electrode side in pixel units, so as to be related to the dot size. It is an object of the present invention to provide a continuous jet type ink jet recording apparatus in which the recording dots can be accurately positioned without performing the operation.

It is another object of the present invention to change only the jet trajectory of recording ink particles and keep the jet trajectory of non-recording ink particles (hereinafter, referred to as non-recording ink particles) unchanged. Another object of the present invention is to provide a continuous jet type ink jet recording apparatus having a high separation stability between recording ink particles and non-recording ink particles by means.

Still another object of the present invention is to provide a continuous jet type ink jet recording apparatus capable of recording a recording dot at a predetermined dot position irrespective of a dot size and maintaining a conventional recording speed. is there.

[0013]

According to the present invention, a continuous jet type ink jet recording apparatus uses a pixel density data for one pixel.
Variable the number of ink droplets
Continuations that can be used to express shades by changing
In an ejection type ink jet recording apparatus, a pressurized ink is guided to eject a jet from a nozzle, and the jet has a uniform size in synchronization with a particleization frequency signal applied to a vibrator mounted on the nozzle. Jet forming means for splitting into ink particles having: a control electrode disposed in front of the nozzle to which a charging control voltage having a potential difference from the ink in the nozzle is applied to charge the jet; and a jet disposed in front of the control electrode. A deflecting means comprising a deflecting electrode and a ground electrode for forming a constant electric field orthogonal to the flight axis to deflect the charged ink particles in the direction of the electric field, and passing the ink particles which are straight or deflected to the deflecting electrode side, Separating means for blocking ink particles deflected to the ground electrode side, and a particle frequency signal corresponding to the value of the pixel density data
Signal that outputs a PWM signal with a pulse width that is an integral multiple of the
Loose width modulation means and when the PWM signal is active
The larger the value of the pixel density data, the earlier the ink particle
A charge compensator for charging a charge having a polarity deflected to the deflection electrode side.
A charge correction signal generating means for generating a positive signal;
When the signal is active, the ground electrode side
Generates a charge control signal to charge electric charges of a polarity that deflects
And a superposition signal of the charge control signal and the charge correction signal.
High voltage for applying a charge control voltage corresponding to
And switch means .

Further, the continuous jet type ink jet recording apparatus of the present invention drives one pixel using the pixel density data.
Change the dot size by variably controlling the number of ink particles
Continuous injection type
In a jet recording apparatus, pressurized ink is guided to eject a jet from a nozzle, and the jet is split into ink particles having a uniform size in synchronization with a particle frequency signal applied to a vibrator mounted on the nozzle. A jet forming means to be disposed; a control electrode disposed in front of the nozzle to which a charging control voltage having a potential difference from the ink in the nozzle is applied to charge the jet; and a fixed electrode disposed in front of the control electrode and orthogonal to the jet flight axis. A deflecting means comprising a deflecting electrode and a ground electrode for forming an electric field to deflect the charged ink particles in the direction of the electric field; and a deflecting means for passing the ink particles which are straight or deflected to the deflecting electrode side and deflected to the ground electrode side. separating means for blocking the ink particles, the
Of the period of the particleization frequency signal according to the value of the pixel density data
Pulse width modulation for outputting a PWM signal with an integral multiple of pulse width
Means and the pixel when the PWM signal is active
The larger the value of the density data, the more the deflection electrode
Generates a charge correction signal that charges the charge with the
And the charge correction signal is transmitted to the jet forming means.
Means for generating a charge correction signal to be applied to the
When the M signal is active, the ground electrode
Generates a charge control signal to charge the charge of the polarity deflected to the
The charging control voltage corresponding to this charging control signal is
High-voltage switch means for applying a voltage to the control electrode .

[0015]

In the continuous jet type ink jet recording apparatus of the present invention, the jet forming means jets the jet from the nozzle, and the jet is applied to the vibrator mounted on the nozzle.
The ink is divided into ink particles having a uniform size in synchronization with the emulation frequency signal , and the control electrode applies a charge control voltage having a potential difference to the ink in the nozzle to charge the jet,
A deflecting means comprising a deflecting electrode and a ground electrode forms a constant electric field orthogonal to the jet flight axis to deflect the charged ink particles in the direction of the electric field, and the separating means moves the ink particles straight or deflected to the deflecting electrode side. The ink particles passed through and deflected to the ground electrode side are blocked. Pulse width modulation means
Is the period of the particle frequency signal according to the value of the pixel density data
A PWM signal with a pulse width that is an integral multiple of
The signal generation means uses the pixel density when the PWM signal is active.
The larger the data value, the more the ink particles are deflected to the deflection electrode side
Generates a charge correction signal to charge the charge of
The pressure switch means is turned on when the PWM signal is active.
Charge particles with polarities that deflect to the ground electrode side
A charge control signal is generated, and a charge control signal, a charge correction signal,
Is applied to the control electrode.
You .

Further, the continuous jet type ink jet recording apparatus of the present invention, indicia oscillator jet forming means is attached to the jet ejects a jet from the nozzle to the nozzle
The ink is divided into ink particles having a uniform size in synchronization with the applied particleization frequency signal , and the control electrode applies a charge control voltage having a potential difference from the ink in the nozzle to charge the jet, and the deflection electrode and the ground electrode Deflecting means, which forms a constant electric field orthogonal to the jet flight axis, deflects the charged ink particles in the direction of the electric field, and the separating means passes through the ink particles which are straight or deflected to the deflecting electrode side and the ground electrode side. To block the deflected ink particles. pulse
The width modulation means controls the particleization frequency according to the value of the pixel density data.
Outputting a PWM signal with a pulse width that is an integral multiple of the signal period,
When the charge correction signal generating means is active with the PWM signal
The larger the value of the pixel density data, the larger the deflection
Charge correction signal for charging the electric charge of the polarity deflected to the pole side.
Generated, and the charge correction signal
High-voltage switch means to activate the PWM signal.
Polarity that deflects ink particles to the ground electrode side when active
Generates a charge control signal for charging the
A charging control voltage corresponding to the signal is applied to the control electrode .

[0017]

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

FIG. 1 is a block diagram showing a continuous jet type ink jet recording apparatus according to a first embodiment of the present invention. First
The continuous jet type ink jet recording apparatus of the embodiment is shown in FIG.
, A data converter DC and a D / A converter (negative) DA
N is added. Therefore, the other parts are configured in the same manner as the corresponding parts in the conventional continuous ejection type ink jet recording apparatus shown in FIG. 17, and the corresponding parts are denoted by the same reference numerals and detailed description is omitted. (The same applies to the following examples).

The data converter DC has a line buffer LB
The pixel density data D _P which is output from and input in synchronization with the encoder clock f _E, and outputs the data D _A conversion characteristic as shown in FIG. Data converter DC, for example, as shown in FIG. 5, the look-up table LUT for outputting data D _A pixel density data D _P as an address input
It is composed of

The D / A converter (negative) DAN inputs the data D _A which is output from the data converter DC, and outputs a charge correction signal phi _A having a negative characteristic as shown in FIG. However, the D / A converter (negative) DAN is the pulse width modulator PW
PWM signal S _C is active (LOW output from the M
Outputs electrostatic correction signal phi _A which only converts the data D _A at level), and outputs the 0V when not active (HIGH level) (see FIG. 4).

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

The oscillator OSC has a constant particleization frequency f _d
In oscillation, and outputs the disintegrating frequency signal f _d.

The vibrator driver CD amplifies the particle frequency signal f _d from the oscillator OSC to drive the piezo vibrator 3, and synchronizes the ink jet emitted from the nozzle 1 with the particle frequency f _d in a series. Split into rows of ink particles.

On the other hand, a pulse width modulator PWM has a pixel density data D _P which is the output of the line buffer LB, output and disintegrating frequency signal f _d is the oscillator OSC, the encoder clock f which is the output of the shaft encoder SE type and _E, under stand in synchronization with the encoder clock f _E is
Ri corresponding to the value of the pixel density data D _P disintegrating frequency signal f
PWM signal of an integral multiple of the pulse width of the periodic 1 / f _d of _d S _C
Is output.

The data converter DC receives the pixel density data D _P and the encoder clock f _E, and outputs data D _A obtained by converting the pixel density data D _P in synchronization with the encoder clock f _E.

Next, the D / A converter (negative) DAN receives the data D _A and the PWM signal S _C, and converts the data D _A only when the PWM signal S _C is active. Output _A.

The high voltage switch HVS receives the PWM signal S _C and the charge correction signal φ _A, and charges the charge control signal φ _C obtained by converting the PWM signal S _C to a high voltage with the charge control voltage ( _A ) superimposed thereon. φ _C + φ _A ) is applied to the control electrode 4. As a result, the charging of the ink particle row emitted from the nozzle 1 is controlled by the control electrode 4.

The charge correction signal φ _A is, as shown in FIG.
The active level (0 V) of the charge control signal φ _C is corrected in the negative direction according to the pulse width (pixel density) of the PWM signal S _C. As can be seen from Figure 4, the charge correction signal phi _A is greater the value of the pixel density data D _P absolute value is large, the ink particles are more positively charged above the knife edge 6 (deflection electrode 8 side) Will be displaced. As a result, the dot position deviation caused by the deceleration of the ink particles by air resistance is corrected by the given correction charge to the recording ink particles by electrostatic correction signal phi _A corresponding to the value of the pixel density data D _P (in Figure 1 (See the rotation direction of the rotary drum DR), and the recording ink particle row is recorded at a predetermined dot position on the recording medium RM regardless of the dot size.

The characteristic curve of the data converter DC in FIG. 2 and the characteristic curve of the D / A converter (negative) dan in FIG. 3 are experimentally determined so that the recording dot position does not shift due to the difference in dot size. .

[0030] Incidentally, according to the continuous jet type ink jet recording apparatus of the first embodiment, as can be seen from FIG. 4, since the charge potential V _C is always kept constant, the charge correction signal phi _A is the control electrode 4 Even when the voltage is applied, the separation of the recording ink particle row from the non-recording ink particle row by the knife edge 6 is stably maintained.

Incidentally, the delay caused by the air resistance to the recording ink particle array forming the pixel may be affected not only by the configuration of the recording ink particle array of the own pixel but also by the recording ink particle array of the preceding pixel. In particular, when the maximum number of ink particles constituting one pixel is small, that is, in the case of image recording with a small number of gradations, this effect must be particularly considered. FIGS. 6A, 6B and 6C are circuit diagrams each showing an example of the data converter DC in which the look-up table LUT is configured in consideration of the previous history (preceding pixel density data).

FIG. 6A is a circuit diagram showing an example of a data converter DC using a look-up table LUT created in consideration of the preceding pixel density data DP _-1 for one pixel. The data converter DC includes a one-pixel delay circuit PDC and a look-up table LUT. In the data converter DC, and the pixel density data D _P to be recorded, the pixel density data D _{P- 1} delayed one pixel by one pixel delay circuit PDC and the look-up table LU
Is input to the T, the recording pixel density data D _P and the data D _A that takes into account the pixel density data D _P-1 to 1 pixel ahead is output from the look-up table LUT. The table data of the lookup table LUT is determined by an experiment as described above.

FIG. 6B shows an example of a data converter DC using a look-up table LUT created in consideration of the preceding pixel density data D _P-1 and D _P-2 for two pixels. It is a circuit diagram. This data converter DC has 2
Stage one-pixel delay circuit PDC and look-up table L
And UT. In the data converter DC, and the pixel density data D _P to be recorded, one-pixel delay circuits P
And pixel density data D _P-1 delayed by one pixel by DC, the pixel density data D _P-2 was delayed by two pixels by 1 pixel delay circuit PDC in two stages is input to a look-up table LUT, the pixel density data to be recorded D _P, 1 pixel preceding the pixel density data D _P-1 and the data D _a that takes into account the pixel density data D _P-2 to 2 pixels prior are output from the look-up table LUT. Lookup table LUT
Is determined by experiments as described above.

FIG. 6C shows data conversion using a look-up table LUT created in consideration of preceding pixel density data D _{P-1 to} D _Pn for n (n is an integer of 3 or more) pixels. FIG. 3 is a circuit diagram illustrating an example of a circuit DC. This data converter DC is composed of an n-stage one-pixel delay circuit PDC and a look-up table LUT. In the data converter DC, and the pixel density data D _P to be recorded, 1
The pixel density data DP _-1 delayed by one pixel by the pixel delay circuit PDC and the pixel density data _DPn delayed by n pixels by the n-stage one-pixel delay circuit PDC are input to the look-up table LUT and recorded. Pixel density data D _P , 1
Pixel density data D _P-1 to pixel preceding, ..., data D _A that takes into account the pixel density data D _Pn preceding n pixels are output from the look-up table LUT. The table data of the lookup table LUT is determined by an experiment as described above.

When a data converter DC as shown in FIGS. 6A, 6B and 6C is used, by taking the previous history (preceding pixel density data) into account, the recording dot of the recording dot can be further increased. A high-quality image with no displacement can be obtained.

The inventor of the present application has connected a bias voltage generator BS whose output voltage can be varied to the control electrode 4,
An equal amount of bias charge is applied to both the non-charged ink particles and the charged ink particles to control the jet flight axis, always maintain the optimum distance between the jet flight axis and the knife edge 6, and separate the jet. Has already been proposed (Japanese Patent Laid-Open No. 5-2).
No. 46036).

FIG. 7 is a block diagram showing a main part of a continuous jet type ink jet recording apparatus according to a second embodiment of the present invention. The continuous ejection type ink jet recording apparatus of the present embodiment
The automatic jet ink jet shaft adjusting device is incorporated in the continuous jet ink jet recording apparatus of the first embodiment shown in FIG. That is, in the continuous ejection type ink jet recording apparatus of the first embodiment, a conductive particle catcher 9 disposed at a home position in front of the ground electrode 5 and the deflection electrode 8 and a shield wire 10 connected to the conductive particle catcher 9 are provided. , A current detector CTD connected to the shield wire 10, and an A / D connected to the current detector CTD.
Converter ADC and MPU (MicroProcessor Unit) 1 of continuous ejection type ink jet recording apparatus
1 and a bias voltage generator BS for applying a bias signal φ _B (adjustable variable voltage V _B ) to the high-voltage switch HVS via a D / A converter (negative) DAN.

In the continuous jet type ink jet recording apparatus of the second embodiment thus constructed, the high voltage switch HVS
Of the charge control signal phi _C and the D / A converter (negative) DAN charge correction signal phi _A and the superimposed voltage (φ _C + φ _A) further bias signal phi _B is superimposed charge control voltage (φ _C + φ _A +
φ _B ) is applied to the control electrode 4. That is, the charging control voltage (φ _C + φ _A + φ _B ) applied to the control electrode 4 is:
As shown in FIG. 8, the charge control voltage (φ _C) in the continuous ejection type ink jet recording apparatus of the first embodiment shown in FIG.
+ Φ _A ) becomes a waveform shifted by the DC bias (φ _B ).

The charging control voltage (φ _C + φ _A + φ
_In the state where _B ) is applied to the control electrode 4, the nozzle 1
When the ink jet is started from the nozzle 1 at the home position, the ink particles charged by the control electrode 4 are cut by the knife edge 6 according to the charged charge, or the conductive particles are not cut by the knife edge 6. It is caught at 9. The minute current due to the charged charges of the ink particles caught by the conductive particle catcher 9 is detected by the current detector CTD through the shield line 10, converted into digital data by the A / D converter ADC, and input to the MPU 11. MPU11 determines a bias signal phi _B instructs its output to the bias voltage generator BS to be applied to the high voltage switch HVS on the basis of the digital data. When applying a bias signal phi _B to the control electrode 4 through the D / A converter (negative) DAN and high voltage switch HVS, with an equal amount of bias charge is applied to the recording ink particles and non-recording ink particles, the jet flying The shaft is displaced toward the deflection electrode 8 or the ground electrode 5. MP
U11, by repeating the determination of the measurement and the bias signal phi _B of the minute current, automatically adjusted to be the position of the jet flying axis and the knife edge 6 (distance) related to the optimum position.

FIG. 9 is a block diagram showing a continuous jet type ink jet recording apparatus according to a third embodiment of the present invention. The continuous ejection type ink jet recording apparatus of the present embodiment is different from the continuous ejection type ink jet recording apparatus of the first embodiment in terms of D / A.
Replace converter (negative) DAN outputs of opposite polarity of the charge correction signal phi _A D / A converter (positive) DAP, and D / A converter (positive) output of the DAP is connected to the ink electrode 2, electrostatic correction signal phi _a is those to be applied to the ink in the nozzle 2.

As shown in FIG. 10, the data converter DC has the same conversion characteristics as the data converter DC in the continuous ejection type ink jet recording apparatus of the first embodiment shown in FIG.

As shown in FIG. 11, the D / A converter (positive) DAP has a polarity opposite to that of the D / A converter (negative) DAN in the continuous jet type ink jet recording apparatus of the first embodiment shown in FIG. It has the following characteristics.

Also in the continuous jet type ink jet recording apparatus of the third embodiment, the potential difference (φ _C −φ _A ) applied between the control electrode 4 and the ink electrode 2 is as follows.
As shown in FIG. 12, the jet is charged in the same manner as in the continuous jet type ink jet recording apparatus of the first embodiment. Therefore, even in a continuous jet type ink jet recording apparatus of the third embodiment, the dot position misalignment due to deceleration of the ink particles by the air resistance, the pixel density data D _P
Is corrected by the correction charge given to the recording ink particles by the charge correction signal φ _A according to the value of the recording ink particles, and the recording ink particle row is recorded at a predetermined dot position on the recording medium RM regardless of the dot size. Needless to say.

FIG. 13 is a block diagram showing a main part of a continuous jet type ink jet recording apparatus according to a fourth embodiment of the present invention. The continuous ejection type ink jet recording apparatus of the fourth embodiment is different from the continuous ejection type ink jet recording apparatus of the third embodiment in that an automatic adjustment device for the jet ejection axis (see Japanese Patent Laid-Open No. 5-2 / 1993).
No. 46036). That is, the bias signal φ _B is added to the charge correction signal φ _A in the continuous ejection type ink jet recording apparatus of the third embodiment.
Are superimposed so that the bias voltage generator BS and the like
Connected to A-converter (positive) DAP. The same bias voltage generator BS as that of the continuous ejection type ink jet recording apparatus of the second embodiment shown in FIG. 7 is used.
From PU11 is commanded to output a reverse polarity of the bias signal phi _B.

In the continuous jet type ink jet recording apparatus of the fourth embodiment configured as described above, the potential difference (φ _C − (φ _A +) applied between the control electrode 4 and the ink electrode 2.
φ _B )) is as shown in FIG. 14, and the bias signal φ _B output from the bias voltage generator BS is the same as in the continuous ejection type ink jet recording apparatus of the second embodiment shown in FIG. is shifted by a DC bias component (phi _B) the potential difference applied to (φ _C -φ _a) between the control electrode 4 and the ink electrode 2.

FIG. 15 is a block diagram showing a main part of a continuous jet type ink jet recording apparatus according to a fifth embodiment of the present invention. The continuous ejection type ink jet recording apparatus according to the fifth embodiment is different from the continuous ejection type ink jet recording apparatus according to the first embodiment shown in FIG. 1 in that the apparatus for automatically adjusting the jet ejection axis (see JP-A-5-246036). It is intended to be incorporated. That is, the bias voltage generator BS is added to the continuous ejection type ink jet recording apparatus of the first embodiment.
By connecting additional to the output of the bias voltage generator BS etc. in ink electrode 2 is obtained by a bias signal phi _B to be applied to the ink in the nozzle 2.

The same effect as that of the continuous jet ink jet recording apparatus of the second embodiment shown in FIG. 7 can be obtained also in the continuous jet ink jet recording apparatus of the fifth embodiment constructed as described above. Needless to say.

FIG. 16 is a block diagram showing a main part of a continuous jet type ink jet recording apparatus according to a sixth embodiment of the present invention. The continuous ejection type ink jet recording apparatus according to the sixth embodiment is different from the continuous ejection type ink jet recording apparatus according to the third embodiment shown in FIG. 9 in that the automatic jet ejection axis adjusting device (see JP-A-5-246036) is used. It is intended to be incorporated. That is, the bias voltage generator BS is added to the continuous ejection type ink jet recording apparatus of the third embodiment.
By connecting the output of the bias voltage generator BS to the high-pressure switch HVS by adding, in which so as to apply to the control electrode 4 by superimposing a bias signal phi _B to the charge control signal phi _C.

The same effect as in the continuous jet ink jet recording apparatus of the fourth embodiment shown in FIG. 13 can be obtained in the continuous jet ink jet recording apparatus of the sixth embodiment constructed as described above. Needless to say.

[0050]

As described above, according to the present invention, the charge control voltage in which the charge control signal from the first control voltage generator and the charge correction signal from the second control voltage generator are superimposed on the control electrode. Is applied, a correction charge corresponding to the dot size is given to the recording ink particles, and the recording dot can be accurately positioned regardless of the dot size by displacing the jet flight axis to the deflection electrode side in pixel units. This has the effect.

Further, by applying a charging control signal from the first control voltage generating means to the control electrode and applying a charging correction signal from the second control voltage generating means to the ink electrode, the recording ink particles By applying a correction charge corresponding to the dot size and displacing the jet flight axis toward the deflection electrode in pixel units, there is an effect that the recording dots can be accurately positioned regardless of the dot size.

Further, by changing only the jet flight axis of the recording ink particles and keeping the jet flight axis of the non-recording ink particles unchanged, the separation between the recording ink particles and the non-recording ink particles by the separating means is stably maintained. There is an effect that can be.

Further, by displacing the recording ink particle array to the deflection electrode side in pixel units, there is an effect that accurate dot positioning becomes possible regardless of the dot size without impairing the recording speed.

[Brief description of the 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 graph showing characteristics of the data converter in FIG.

FIG. 3 is a graph showing characteristics of a D / A converter (negative) in FIG. 1;

FIG. 4 is a timing chart showing a timing of generating a charge control voltage in the continuous jet type ink jet recording apparatus of the first embodiment.

FIG. 5 is a diagram illustrating an example of a data converter in FIG. 1;

6 (a) to 6 (c) are diagrams each showing an example in consideration of preceding pixel density data of the data converter in FIG. 1;

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

FIG. 8 is a timing chart showing a timing of generating a charge control voltage in the continuous jet type ink jet recording apparatus of the second embodiment.

FIG. 9 is a configuration diagram illustrating a continuous ejection type ink jet recording apparatus according to a third embodiment of the present invention.

FIG. 10 is a graph showing characteristics of the data converter in FIG. 9;

11 is a graph showing characteristics of the D / A converter (positive) in FIG.

FIG. 12 is a timing chart showing a timing of generating a charge control voltage in the continuous ejection type ink jet recording apparatus of the third embodiment.

FIG. 13 is a configuration diagram showing a main part of a continuous ejection type ink jet recording apparatus according to a fourth embodiment of the present invention.

FIG. 14 is a timing chart showing a timing of generating a charge control voltage in the continuous ejection type ink jet recording apparatus of the fourth embodiment.

FIG. 15 is a configuration diagram showing a main part of a continuous ejection type ink jet recording apparatus according to a fifth embodiment of the present invention.

FIG. 16 is a configuration diagram showing a main part of a continuous jet ink jet recording apparatus according to a sixth embodiment of the present invention.

FIG. 17 is a configuration diagram showing an example of a conventional continuous jet type ink jet recording apparatus.

FIG. 18 is a timing chart for explaining a principle of variably controlling a recording dot diameter by pulse width modulation in a conventional continuous ejection type ink jet recording apparatus.

FIG. 19 is a diagram illustrating that a recording dot misalignment occurs according to a dot size in a conventional continuous ejection type ink jet recording apparatus.

[Explanation of symbols]

Reference Signs List 1 nozzle 2 ink electrode 3 piezo oscillator 4 control electrode 5 ground electrode 6 knife edge 7 deflection power supply 8 deflection electrode 9 conductive particle catcher 10 shield wire 11 MPU ADC A / D converter CD oscillator driver CTD current detector D _A Data DAN D / A converter (negative) DAP D / A converter (positive) DC data converter D _P pixel density data DR Rotary drum f _d Particle frequency signal f _E Encoder clock HVS High voltage switch LB Line buffer OSC oscillator PWM Pulse width modulator S _C PWM signal SE Shaft encoder φ _A charging correction signal φ _B bias signal φ _C charging control signal

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/055 B41J 2/075

Claims (10)

(57) [Claims] (1)Driving one pixel using pixel density data
Variable the number of ink particles to change the dot size
Continuous injection type
In the ink jet recording device,  The pressurized ink is guided and ejects a jet from the nozzle,
Vibrator with jet mounted on nozzleParticles applied to
Frequency signalInk particles having a uniform size in synchronization with
Jet forming means for splitting the ink into a plurality of nozzles,
HaveCharge control voltage appliedCharged jet
A control electrode, which is disposed in front of the control electrode and is orthogonal to the jet flight axis.
A constant electric field to move the charged ink particles in the direction of the electric field.
Deflecting means comprising a deflecting electrode for deflecting light and a ground electrode
And the ink particles that go straight or are deflected to the deflection electrode side
To block the ink particles deflected to the ground electrode side.
Separation means for disconnecting;The frequency of the particleization frequency signal corresponding to the value of the pixel density data
Pulse width that outputs a PWM signal with a pulse width that is an integral multiple of the period
Modulation means; When the PWM signal is active, the pixel density data
The larger the value of the data, the more the ink particles are deflected to the deflection electrode side.
Band that generates a charge correction signal that charges the charge of
Electric correction signal generating means, When the PWM signal is active,
Charging control to charge the electric charge of the polarity deflected to the ground electrode side
Signal, and the charge control signal and the charge correction signal
Charging control voltage corresponding to the superimposed signal of
High pressure switch means Continuation characterized by including
Injection type inkjet recording device. 2. A charge correction signal generating means,
To maintain a constant gap between the jet flight axis and the separation means
Generating a variable voltage, and charging the variable voltage
2. The continuous jet type ink jet recording apparatus according to claim 1, further comprising a bias voltage generating means for superimposing the bias voltage on the correction signal . 3. A is connected to the ink electrodes in said jet forming means, the adjustment variable voltage to keep the gap between the separating means and the jet flying axis constant occurs, the adjustment variable voltage
2. A continuous jet type ink jet recording apparatus according to claim 1, further comprising: a bias voltage generating means for applying a bias voltage to said ink electrode . (4)Driving one pixel using pixel density data
Variable the number of ink particles to change the dot size
Continuous injection type
In the ink jet recording device,  The pressurized ink is guided and ejects a jet from the nozzle,
Vibrator with jet mounted on nozzleParticles applied to
Frequency signalInk particles having a uniform size in synchronization with
Jet forming means for splitting the ink into a plurality of nozzles,
HaveCharge control voltage appliedCharged jet
A control electrode, which is disposed in front of the control electrode and is orthogonal to the jet flight axis.
A constant electric field to move the charged ink particles in the direction of the electric field.
Deflecting means comprising a deflecting electrode for deflecting light and a ground electrode
And the ink particles that go straight or are deflected to the deflection electrode side
To block the ink particles deflected to the ground electrode side.
Separation means for disconnecting;The frequency of the particleization frequency signal corresponding to the value of the pixel density data
Pulse width that outputs a PWM signal with a pulse width that is an integral multiple of the period
Modulation means; When the PWM signal is active, the pixel density data
The larger the value of the data, the more the ink particles are deflected to the deflection electrode side.
Generates a charge correction signal that charges the charge of
Charge correction signal to the ink electrode in the jet forming means.
Charge correction signal generating means to be applied to When the PWM signal is active,
Charging control to charge the electric charge of the polarity deflected to the ground electrode side
Signal to generate a charge control signal corresponding to this charge control signal.
High pressure switch means for applying pressure to the control electrode; including
A continuous jet type ink jet recording apparatus characterized by the above-mentioned. 5. A gap between a jet flight axis and said separating means.
Generates an adjustable variable voltage that keeps the
The voltage is superimposed on the charge correction signal of the charge correction signal generating means.
5. The continuous ejection type ink jet recording apparatus according to claim 4, further comprising a bias voltage generating means . 6. A gap between a jet flight axis and said separation means.
Generates an adjustable variable voltage that is kept constant, and
A voltage that superimposes the pressure on the charging control voltage of the high-voltage switch means.
5. The continuous ejection type ink jet recording apparatus according to claim 4, further comprising a bias voltage generating means . 7. A charge correction signal of said charge correction signal generating means.
No. continuous jet type ink jet recording apparatus to 6 according claims 1 changes according to the target pixel density data. 8. A charge correction signal of said charge correction signal generating means.
No. continuous jet type ink jet recording apparatus of claims 1 to 6, wherein changes in accordance with the preceding pixel density data with own pixel density data. 9. A charge control signal and a charge control signal for said high voltage switch means.
9. The continuous ejection type ink jet recording apparatus according to claim 1, wherein a charge correction signal of said charge correction signal generating means changes in synchronization with a pixel recording command signal and a particleization frequency signal. 10. The charge correction signal generating means includes a look-up table constituted by a rewritable memory having pixel density data as an address input.
A continuous jet ink jet recording apparatus as described in the above.