JPH1191099A - Ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ink jet recording apparatus capable of being inexpensively realized by enabling the setting of drive data to be allowed to correspond to a sonic wave generation element by relatively simple constitution while employing a lenear electronic scanning method principally reduced in clogging. SOLUTION: In the drive circuit of a ink jet recording apparatus wherein a plurality of piezoelectric elements are simultaneously driven as one group according to the drive data corresponding to image data to fly ink liquid droplets to perform recording, drive data row buffers 55, 65 storing drive data rows for driving respective piezoelectric elements in the group are provided and the drive data rows stored in them are successively read corresponding to the respective piezoelectric elements in the group through selectors 56, 66 and repeatedly read corresponding to each of respective groups and the AND operation with the image data inputted from a line memory through a latch is performed in AND circuits 57, 67 to form the drive data corresponding to the image data.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus for recording an image by flying ink droplets, and more particularly to generating an acoustic wave beam by driving a plurality of acoustic wave generating elements individually and substantially simultaneously. The present invention relates to an ink jet recording apparatus for causing ink droplets to fly.

[0002]

2. Description of the Related Art An ink jet recording apparatus for recording an image by flying liquid ink as small droplets onto a recording medium has many advantages such as being able to directly record on plain paper. However, the ink jet recording apparatus is liable to concentrate the ink due to evaporation and volatilization of the solvent of the liquid ink, so that the nozzle for flying the ink droplets is clogged, which causes a problem in that the ink droplets fly. there were.

In a so-called line type head having a large number of nozzles, it is indispensable to prevent the clogging. For this reason, it is necessary to provide additional means such as cleaning the nozzles, or use a nozzle having a small diameter. There were problems such as inability to do so. That is, in the conventional inkjet recording apparatus, the reliability of the line type head is low, and the higher the resolution, the more difficult it is to use.

In order to overcome these drawbacks, IBM TDB, vol. 16, No. 1, discloses a method in which ink is ejected from an ink liquid surface using the pressure of an ultrasonic beam generated by a piezoelectric element array constituted by a thin film piezoelectric material. .4, pp.1168 (1973-10), US
P-4308547 (1981), USP-4697195 (1987), USP-4751529
(1988), USP-4751530 (1988), USP-5041849 (1991),
JP-A-62-66943, JP-A-63-162253, JP-A-63-166545
JP-A-63-166546, JP-A-63-166548, JP-A-63-31
2157, JP-A-3-200199, JP-A-4-296562, JP-A-4-296
563, JP-A-4-356328 and JP-A-5-278218.

This method is a so-called nozzleless method that does not require a nozzle for each dot or a partition wall of an ink flow path, and is advantageous in preventing clogging, which has been a major obstacle in forming a line head. In addition, since an ink droplet having a very small diameter can be stably generated and fly, it is also suitable for high resolution.

However, this method uses an acoustic lens having a diameter larger than the recording pixel or the recording resolution, for example, 30 times as large as the recording pixel, to focus the ultrasonic beam into the ink. You must widen the space at which you can fly. Normally, a recording head is configured by arranging a plurality of piezoelectric element arrays in a staggered manner in order to narrow the flight interval of ink droplets.However, periodic density unevenness due to staggered arrangement and slight misalignment with adjacent dots There is a problem that the image quality affects the image quality.

Therefore, Japanese Patent Application Laid-Open No. 2-184443 discloses another method of converging an ultrasonic beam, in which a plurality of piezoelectric elements are arranged at a predetermined interval and each piezoelectric element of a piezoelectric element array is provided with a predetermined delay time difference. A method referred to as a sector electronic scanning method has been proposed in which an ultrasonic wave having a controlled phase is excited by being applied and driven to focus an ultrasonic beam at a point near an ink liquid surface. According to this method, it is possible to perform high-resolution recording by changing the flying position of the ink droplet without being limited by the arrangement pitch of the piezoelectric element array.

However, in the sector electronic scanning method, in order to cause ink droplets to fly at desired positions on the ink liquid surface, it is necessary to drive a piezoelectric element so that an ultrasonic beam is focused on each position. It is necessary to accurately calculate and control the delay time difference, and the driving circuit becomes complicated and expensive. Further, when the ink droplet is caused to fly at a position other than one point on the ink liquid surface which coincides with the center position of the piezoelectric element array, the focused ultrasonic wave has directionality, so that the ink droplet There is a problem that the ink droplets fly obliquely with respect to the ink liquid surface, and as a result, the arrival positions of the ink droplets are shifted due to a change in the height of the ink liquid surface or the distance between the ink liquid surface and the paper.

In order to solve such a problem, a part of a plurality of predetermined piezoelectric elements (piezoelectric element group) in a piezoelectric element array
A method called linear electronic scanning has been proposed in which a plurality of piezoelectric elements are simultaneously driven to fly one ink droplet, and the positions of the piezoelectric elements that are simultaneously driven are sequentially shifted to move the flying position of the ink droplet. In this method, since the delay time for each piezoelectric element is set to be symmetrical with respect to the center of the piezoelectric element group, the ink droplet always flies linearly in a direction perpendicular to the liquid surface. Furthermore, as a method of eliminating the trouble of controlling the delay time, a more simple method of dividing the piezoelectric element array into two groups based on the Fresnel diffraction theory and setting the delay times so that the phases are different from each other by a half wavelength is adopted. Methods have also been proposed.

In a piezoelectric element array driving circuit for realizing such a linear electronic scanning method, a group of piezoelectric elements to be driven must be selected based on image data.
That is, in the linear electronic scanning method, since the number of piezoelectric elements to be simultaneously driven becomes plural for image data corresponding to one image point, one pixel data is used for one image data used in a normal inkjet recording apparatus. A driving circuit having a special configuration completely different from the configuration in which one driving element is made to correspond is required.

In a conventional ink jet recording apparatus using the linear electronic scanning method, ink droplets are ejected at intervals equal to the arrangement pitch of the piezoelectric element array, and the ink droplets are ejected at intervals smaller than the arrangement pitch. Is difficult, and there is a limit in increasing the recording resolution.

[0012]

As described above, the ink jet recording apparatus of the type in which the piezoelectric element array is driven by the linear electronic scanning method to fly the ink droplets,
Although recording without clogging is possible in principle, it is necessary to drive a plurality of piezoelectric elements at the same time according to the image data to be recorded to fly one ink droplet. The issue was how to configure.

In the conventional ink jet recording apparatus using the linear electronic scanning method, ink droplets are ejected at intervals equal to the arrangement pitch of the piezoelectric element array, and the ink droplets are ejected at intervals smaller than the arrangement pitch. Is difficult, and there is a limit in increasing the recording resolution.

A first object of the present invention is to make it possible to set drive data to be made compatible with a sound wave generating element with a relatively simple configuration while adopting a linear electronic scanning method with less clogging in principle, and to reduce the cost. An object of the present invention is to provide an ink jet recording apparatus that can be realized.

A second object of the present invention is to provide an ink jet recording apparatus capable of recording at a higher resolution by causing ink droplets to fly at a pitch smaller than the arrangement pitch of the sound wave generating element array.

[0016]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, according to the present invention, a plurality of predetermined sound wave generating elements in a sound wave generating element array are grouped into one group, and each sound wave generating element in the group is image data. In an ink jet recording apparatus that performs recording by causing ink droplets to fly in groups by individually and substantially simultaneously driving according to drive data corresponding to a set of signals for driving each sound wave generating element in the group. The driving data string including the driving data is stored in the driving data string buffer, and the driving data string stored in the driving data string buffer is sequentially assigned to each sound wave generating element in the group and assigned to each group. It is characterized by generating drive data according to the image data by repeatedly reading out correspondingly and performing a logical product operation with the image data. To.

The drive data thus generated is sequentially transferred, for example, on a shift register to the next stage, and each sound wave generating element is driven according to the output of each stage of the shift register. The drive data sequence is constituted by data indicating the phase of the drive data corresponding to each sound wave generating element in the group, for example.

As described above, a drive data string composed of the same number of drive data as the number of sound wave generating elements required to fly one ink droplet is set and stored in the buffer, and the stored drive data string is stored in the buffer. Since drive data is generated in accordance with the image data by repeatedly reading, the drive data can be set with a simple configuration, and the capacity of the buffer for storing the drive data string can be minimized.

Further, according to the present invention, a plurality of predetermined sound wave generating elements in a sound wave generating element array are grouped into one group, and each sound wave generating element in this group is individually and substantially simultaneously driven in accordance with drive data corresponding to image data. By doing so, in an ink jet recording apparatus that performs recording by flying ink droplets for each group, a set of drive data for driving each sound wave generating element in the group is formed, and the ink droplets are moved to different positions. One of the first and second drive data strings set to fly to the selected drive data string is selected, and a logical AND operation of the selected drive data string and the image data is performed to obtain the image data. It is characterized in that corresponding drive data is generated.
The generated drive data is sequentially transferred, for example, on the shift register to the next stage, and each sound wave generating element is driven according to the output of each stage of the shift register.

In this case, the selected drive data string is temporarily stored in the drive data string buffer, and the drive data string stored in the drive data string buffer is sequentially stored in correspondence with each sound wave generating element in the group. Alternatively, the data may be repeatedly read out corresponding to each group.

As described above, when the first drive data sequence and the second drive data sequence are switched and selected, the first
A mode in which ink droplets are caused to fly to a first position with respect to the arrangement position of the sound wave generating elements by the drive data train of
The mode in which the ink droplets fly to the second position different from the first position can be easily switched by the driving data sequence of the above. Therefore, without changing the arrangement pitch of the sound wave generating elements, Ink droplets can be made to fly at a pitch smaller than the arrangement pitch, and high-resolution recording can be performed.

Here, the first and second drive data strings are constituted by, for example, data indicating individual phases of drive data corresponding to each sound wave generating element in a group of the sound wave generating element array. Further, at least one of the first and second drive data strings may include at least one non-drive data for turning off the corresponding sound wave generating element.

As a method for selecting one of the first and second drive data strings, for example,
There are two methods.

The first drive data string selection method is a method in which the first and second drive data strings are alternately switched and selected every time the ink droplet flies, and the sound wave generating element array has a simple circuit configuration. High-resolution recording at or above the array pitch, and the simple relationship between the arrangement order of the image data and the flying position of the ink droplets simplifies the method of reading image data. In addition, since the flying positions of the ink droplets are arranged at predetermined intervals in any of the flying operations, the recording operation can be stabilized.

The second drive data string selection method is a method in which the first and second drive data strings are mixed and selected in one ink droplet flying operation. Since the drive data for non-driving the sound wave generator can always be present, the maximum number of simultaneously driven sound wave generators is reduced, and there is an advantage that the power supply capacity of the drive circuit can be reduced. In addition, since non-drive data can be provided at regular intervals in the arrangement direction of the sound wave generating elements, mutual interference during the flight of ink droplets from each group is prevented, and the flying operation can be stabilized. Becomes

The third drive data string selection method is a method of selecting the first and second drive data strings by switching between the first half and the second half of a series of ink droplet flying operation periods in one line. When the flying position of the ink droplet shifts by one pixel in the flying operation, the flying position of the ink droplet is further reduced by 1 /
Since it is separated by two pixels, bleeding of ink droplets after flying and landing on the recording medium is effectively prevented.

[0027]

Embodiments of the present invention will be described below with reference to the drawings. [Overall Configuration of Inkjet Recording Apparatus] FIG. 1 is a perspective view of a main part showing a schematic configuration of an inkjet recording apparatus according to an embodiment of the present invention. First, the flying principle of ink droplets of the ink jet recording apparatus according to the present invention will be briefly described. For details of this principle, reference can be made to Japanese Patent Application No. 6-220713. In the present embodiment, an example will be described in which a piezoelectric element is used as a sound wave generating element and ink droplets are caused to fly by the pressure of an ultrasonic beam. However, an audio frequency sound wave beam may be used.

As shown in FIG. 1, a piezoelectric element array 2 is formed on a glass plate 1 which also serves as a support and an ultrasonic interference layer (acoustic bonding layer). The piezoelectric element array 2 includes a common electrode layer 2a surface-bonded to one main surface of the glass plate 1, and a piezoelectric layer 2b bonded and arranged on the other surface of the common electrode layer 2a.
And an individual electrode layer 2c provided on the other surface of the piezoelectric layer 2b and separating the piezoelectric layer 2b into an array.

A driving circuit 3 for driving the piezoelectric element array 2 is further provided on one main surface of the glass plate 1.
The nozzle substrate 4 is joined and arranged on the other main surface. In the nozzle substrate 4, an ink liquid chamber 5 having a slit-shaped nozzle hole 6 formed by cutting out a trapezoidal cross section is formed. Further, a one-dimensional Fresnel diffraction band plate 7 is formed at the interface between the ink liquid chamber 5 and the glass plate 1.

Here, the piezoelectric element array 2 is composed of the individual electrode layers 2
The piezoelectric element is separated into a plurality of piezoelectric elements corresponding to c. The number of piezoelectric elements is, for example, about 5000 in the case of a line type head of A4 paper size with a resolution of 600 dpi, and the individual electrode layers 2c corresponding to the number of piezoelectric elements are arranged in a line. The piezoelectric element array 2 can be manufactured as follows.

That is, a common electrode layer 2a made of a thin metal layer is formed on one main surface of the glass plate 1 by, for example, a vapor deposition method, and ZnO or P is formed on the common electrode layer 2a.
A piezoelectric material such as bTiZrO ₃ is sputtered to provide a piezoelectric layer 2b. Thereafter, individual electrode layers 2c paired with the common electrode layer 2a are formed on the surface of the piezoelectric layer 2b at a pitch corresponding to the recording bit. The thickness of the piezoelectric layer 2b is determined by the desired ultrasonic wave, and is generally designed to be half the desired ultrasonic wave wavelength including the equivalent thickness of the two electrode layers 2a and 2c.

The one-dimensional Fresnel diffraction zone plate 7, and the distance from the center and ^{x x = 0~1 1/2 k, 3} 1/2 k~5
^1/2 k, 7 ^1/2 k to 9 ^1/2 k, 11 ^1/2 k to 13
^1/2 k, a first region for passing ultrasonic waves to ... position without a phase ^{shift, x = 1 1/2 k~3 1/2 k} , 5 1/2 k
^{~7 1/2 k, 9 1/2 k~11 1/2} k, 13 1/2 k~15
The second regions for shifting the phase of the ultrasonic wave by a half wavelength are alternately arranged at the positions of k ^1/2 . However, when the thickness (focal length) of the nozzle substrate 4 is p and the wavelength of the ultrasonic wave to be used is λ, k = (λp / 2) ^1/2 . Since the first and second regions only need to have a phase difference of relatively half a wavelength, only one of the regions may be formed by photolithography of a metal vapor deposition film, and the thickness of the first and second regions may be within the ink liquid. Is selected to be about several μm to about several tens μm in which a phase shift of a half wavelength occurs due to a difference from the slow sound speed of

(Recording Principle of the Inkjet Recording Apparatus of FIG. 1) Next, a basic recording operation of the inkjet recording apparatus of FIG. 1 will be described with reference to FIGS.
FIG. 2A is a cross-sectional view in a direction orthogonal to the nozzle hole 4, and FIG.
FIG. 2B is a cross-sectional view along the nozzle hole 4.

First, in order to focus the ultrasonic beam on a straight line passing through the center line in the array direction of the piezoelectric element group in the driven group of the piezoelectric element array 2 and intersecting a plane perpendicular to the array direction and the liquid surface. , A burst voltage composed of an alternating current of a predetermined frequency or a pulse train is applied to a part of the piezoelectric element array 2, for example, the individual electrode layers 2 c 1, 2
c2, 2c3, and 2c4. Here, the frequency of the applied burst voltage is set so that the ultrasonic wavelength in the glass plate 1 functioning as the acoustic matching layer is longer than the pitch of the piezoelectric element array 2.

Then, the individual electrode layers 2c1, 2c2, 2c
3 and 2c4, the inner two individual electrode layers 2c2 and 2c
3, a predetermined burst voltage is applied to the two outer electrode layers 2c1 and 2c4 so that the ultrasonic beam is focused on a straight line where the surface perpendicular to the array direction and the liquid surface intersect. A burst voltage having a phase advanced from the individual electrodes 2c2 and 2c3 is applied. At this time, the mutual ultrasonic beams interfere with each other, and a lens effect occurs in the array direction of the piezoelectric element array 2 (main scanning direction).

On the other hand, the ultrasonic beam reaching the interface between the glass plate 1 and the ink liquid chamber 5 is centripetally moved by the Fresnel diffraction band plate 7 in a direction (sub-scanning direction) orthogonal to the array direction of the piezoelectric element array 2. Receives a focusing lens effect. That is, the focusing of the ultrasonic beam in the main scanning direction is performed by the glass plate 1 which also functions as an acoustic matching layer (ultrasonic interference layer).
The focusing in the sub-scanning direction is performed only in the ink liquid chamber 5 of the nozzle substrate 4.

At this time, since the thickness of the nozzle substrate 4 is previously selected and set so as to be in focus, the focus is applied to the surface of the ink liquid by the surface tension in the slit-shaped opening forming the nozzle hole 6. Will be combined. Therefore, the pressure of the ultrasonic beam focused in the main scanning direction and the sub-scanning direction allows the ink droplets to easily fly from the ink liquid surface, and to record a clear image without density unevenness on a recording medium surface (not shown). Can be.

(Driving Method of Inkjet Recording Apparatus) FIGS. 3A to 3D show a case where four adjacent piezoelectric elements in the piezoelectric element array 2 are grouped into one group and an ultrasonic beam is focused on one point. The operation in the case is schematically shown. That is, this is an operation in the case where the image point for one line is formed by dividing it into at least 1/4 lines or more, and the individual electrode layers 2c1, 2c2, 2c3, 2c
4, 2c5, 2c6, 2c7, and 2c8 are applied with a driving voltage while being shifted in the main scanning direction by a linear scanning operation.

That is, among the individual electrode layers 2c2, 2c3, 2c4, 2c5 grouped in FIG.
A predetermined burst voltage is applied to the inner two individual electrode layers 2c3 and 2c4, and the inner two individual electrode layers 2c3 and 2c4 are applied to the outer two individual electrode layers 2c2 and 2c5 as described above.
, A burst voltage having a phase advanced from the phase of the burst voltage applied is applied.

In FIG. 3B, a burst voltage is applied to the inner two individual electrode layers 2c4 and 2c5 of the grouped individual electrode layers 2c3, 2c4, 2c5 and 2c6, and the outer two In the individual electrode layers 2c3 and 2c6, the inner 2
A burst voltage having a phase advanced from the individual electrode layers 2c4 and 2c5 is applied.

In FIG. 3C, of the individual electrode layers 2c4, 2c5, 2c6, 2c7 further grouped, a burst voltage is applied to the inner two individual electrode layers 2c5, 2c6 and the outer two A burst voltage with an advanced phase is applied to the individual electrode layers 2c4 and 2c7.

FIG. 3D shows the individual electrode layers 2c1 and 2c2.
c2, 2c3, 2c4, 2c5, 2c6, 2c7, 2c
8 are divided into a group of individual electrode layers 2c1, 2c2, 2c3, 2c4 and a group of individual electrode layers 2c5, 2c6, 2c7, 2c8, and these two groups are simultaneously driven to form two ink liquids at a predetermined pitch. The operation when flying a droplet is shown.

In this example of operation, one group is composed of four piezoelectric elements in order to record one image point. However, if the number of piezoelectric elements constituting one group is increased, the superposition of centripetal focusing is achieved. Since the wavefront of the sound wave beam becomes smooth and the energy density becomes high, it is possible to reduce the dispersion of the ink droplets and the driving voltage applied to the piezoelectric element array 2.

[Drive Circuit 3 (FIG. 4)] Next, an embodiment of the drive circuit 3 in FIG. 1 will be described. FIG.
FIG. 3 is a block diagram illustrating a main configuration of a driving circuit 3 according to an embodiment. In FIG. 4, a control unit 40 controls the timing of the system, and may include a CPU. The line memory 42 is controlled by a timing signal from the control unit 40, and writes and reads image data.

The drive data generator 43 is provided with a line memory 4
The drive data for driving the piezoelectric elements 48 of the piezoelectric element array 2 in FIG. Here, for the sake of simplicity, the piezoelectric elements 48 are individually shown as 48a, 48b, 48c,..., But can be considered to correspond to the individual electrodes 2c in FIGS. The details of the drive data generation unit 43 will be described later in detail with reference to FIG.

Image data sent from a scanner output or a transmission path (not shown) is input to the line memory 42, and the timing is controlled by the control unit 40 and written into the line memory 42. The image data is 1 in this example.
It is composed of 1-bit data per pixel. The line memory 40 has a capacity of, for example, 4960 bits, and has a capacity of 600
Image data for one line of A4 paper size can be stored at a resolution of dpi.

The image data temporarily stored in the line memory 42 is sequentially read out and sent to the drive data generator 43. The drive data generation unit 43 generates a selection signal for driving the piezoelectric element 48 as described later.

(Operation of Drive Circuit 3 of FIG. 4) Next, the operation of the drive circuit 3 of FIG. 4 will be described with reference to a timing chart of FIG. 6 showing transfer of drive data and drive timing of the piezoelectric element. . The drive circuit 3 starts operating at the rise of the horizontal synchronization signal HSYNC. The drive data generated by the drive data generation unit 43 is provided to an input of a first-stage shift register element 44a of the shift register 44, and the control unit 40
Are sequentially transferred to the next-stage shift register elements 44b, 44c,... In synchronization with the clock SHIFT CLOCK. 49
When all 60 drive data are transferred to the shift register 44, the drive data in the shift register 44 is taken into the latch 45 by the latch signal LATCH CLOCK from the control unit 40.

Further, in the selector 46, the latch 45
2 types of high-frequency signals SIGNAL ZER having different phases from the high-frequency signal generator 41 in accordance with the drive data output from the
One of O, SIGNAL PAI and ground signal GND is selectively output.

The drive data generated by the drive data generator 43 includes these two types of high-frequency signals SIGNAL ZERO and SI
ON / OFF of the driving of the piezoelectric element 48 by each of the GNAL PAI
This is data for controlling off, and is 1-bit data for one high-frequency signal. That is, the driving data is 2
It is output as 2-bit data for turning on / off various kinds of high-frequency signals. Therefore, the shift register 44 and the latch 45 corresponding to one piezoelectric element 48 are configured so as to form a set of two bits. The selection of the high-frequency signal by the selector 46 is performed based on a truth table as shown in FIG.

The high frequency signal output from the selector 46 is amplified by a driver 47 and then applied to a corresponding piezoelectric element 48. A voltage having an amplitude of substantially 10 V to 30 V is applied to one piezoelectric element 48. In order to fly an ink droplet of about 600 dpi, the frequency of the high-frequency signal is selected to be about 50 MHz.

On the other hand, while the burst-like high-frequency signal is being applied to the piezoelectric element 48 in this manner,
Drive data for applying the second high-frequency signal is transferred to the shift register 44, and the application period DR of the first high-frequency signal is applied.
When IVE1, that is, the first ink droplet flying operation ends, the second high-frequency application period DRIVE2 starts. Hereinafter, similarly, the application of the high-frequency signal is repeated, and the recording operation of one line is completed when the required number of times has been performed. In FIG.
For simplicity, an example is shown in which one line is recorded by four flying operations.

(One Embodiment of Drive Data Generation Unit 43 (FIG. 5)) FIG. 5 shows a schematic configuration of the drive data generation unit 43 in FIG. In FIG. 5, drive data string setting sections 54 and 64 are for setting a data string for driving a plurality of piezoelectric elements necessary for flying one ink droplet. When flying one ink droplet by simultaneous driving, four driving data are set as a set of data strings. The drive data string is composed of two types of high-frequency signals SIGNAL Z having different phases as described above.
Two types are prepared to select ERO and SIGNAL PAI.

That is, the drive data generation unit 43 has drive data sequence generation blocks 53 and 63 for generating two types of drive data sequences ZERO-DATA and PAI-DATA corresponding to the two types of high-frequency signals SIGNAL ZERO and SIGNALPAI. ing. These two drive data string generation blocks 53 and 63 can be realized by the same configuration. The drive data string setting units 54 and 64 can have a simple switch configuration, and can be a RAM or RO.
It is also possible to configure using M.

The driving data string buffers 55 and 65 are buffers that take in the driving data strings from the driving data string setting units 54 and 64 and sequentially read out the data constituting the driving data strings one by one in time series. In the present embodiment, the driving data string buffers 55 and 65 are configured by shift registers of parallel input / serial output, and the driving data string setting sections 54 and 6 are controlled by a load signal LOAD CLOCK from the control section 40.
4 is read from the drive data string, and one data of the drive data string is read by a read signal READ CLOCK from the control unit 40.

The selectors 56 and 66 select the drive data sent from the drive data string buffers 55 and 65, respectively, according to the timing selection signal TIMING SELECT from the control unit 40, and send them to the AND circuits 57 and 67.

The AND circuits 57 and 67 include a selector 56,
The logical product of the driving data from the line memory 66 and the image data from the line memory 42 in FIG.
As drive data DRIVE DATA. Here, since it is necessary to make a plurality of drive data correspond to one pixel of image data, in this example, four read signals READ
After transmitting the logical product of the four drive data corresponding to CLOCK and one image data, the process proceeds to the processing of the image data for the next pixel. For this purpose, the line memory 4
A latch 52 is provided to hold one image data read out from 2 only for a period of 4 readings.

In FIG. 5, the line memory 42 shown in FIG.
Is input to the latch 52 via the quantization unit 51. However, when binary data is used as image data as in the present embodiment, the quantization unit 51 No need to work. However, for example, when the image data input to the line memory 42 is multi-valued data such as 8 bits per pixel, the quantization unit 51 performs binarization processing with an appropriate value.

The data transmitted from the AND circuits 57 and 67 in this manner is drive data for driving a predetermined piezoelectric element, and includes high-frequency signals SIGNAL ZERO and SIGNAL P.
This is binary data for selecting AI. High frequency signal SI
Similarly to the generation of the drive data ZERO-DATA for selecting GNAL ZERO, the drive data PAI-DATA for selecting the high-frequency signal SIGNAL PAI is also output. That is, 2-bit data is input to the shift register 44 in FIG.

(Operation of Drive Data Generation Unit 43 in FIG. 5) Next, the operation of the drive data generation unit 43 will be described in more detail with reference to the timing chart of drive data generation and transfer shown in FIG.

As shown in FIG. 7A, first, the control unit 40
In response to the load signal LOAD CLOCK from the drive data string setting unit 54, 64, the drive data string is supplied from the drive data string buffer 5
5, 65. At this time, the image data IMAGE DATA of the first pixel is read from the line memory 42 and temporarily stored in the latch 52. Four drive data DRIVE DATA are read signals for the image data of the first pixel.
Generated in synchronization with READ CLOCK.

Next, the image data of the fifth pixel, which is four pixels ahead of the image data of the first pixel, is read from the line memory 42, and four drive data are generated for the image data of the fifth pixel. Sent out. Hereinafter, similarly, image data shifted by four addresses is read from the line memory 42. That is, the drive data is set so that every fourth ink droplet flies at the position of the piezoelectric element.

When 4960 pieces of drive data are transferred in this way, as described earlier with reference to the timing chart of FIG. 6, the drive data is fetched into the latch 45 by the latch signal LATCH CLOCK, and every four piezoelectric elements are output. A series of recording operations of flying ink droplets from the position are performed.

Since the ink droplets fly every fourth element, the flying position is shifted by one element in the next ink droplet flight. That is, as shown in FIG. 7B, the transfer clock SHIFT CL
The transmission of the OCK is started, but for the first transfer clock, the timing selection signal TIMINGSE
LECT is off, and the outputs of the selectors 56 and 66 in FIG. 5 transmit non-drive data (here, a ground signal GND) without selecting a drive data string. This serves to shift the position of the piezoelectric element used at the time of the previous ink droplet flight by one, and forcibly puts the piezoelectric element corresponding to the extreme end into the non-drive state.

Thereafter, the timing selection signal TIMING SELEC
T is turned on, and a signal equal to or less than the load signal LOAD CLOCK is transmitted in the same manner as in FIG. At this time, the image data read from the line memory 42 is read every fourth pixel, such as the second pixel, the sixth pixel, the tenth pixel, the fourteenth pixel, and so on.

Similarly, as shown in FIG. 7C, the relationship between the timing selection signal TIMING SELECT and the transfer clock SHIFT CLOCK is such that two elements from the end are not driven during the third ink droplet flight. Is set. Although not shown, the same operation is performed during the fourth ink droplet flight,
The flying of all the ink droplets for one line is completed, and the flying of the next line is performed by the same operation as the first line.

(Specific Example of Driving Data Sequence) FIG. 9 shows an example of a driving data sequence composed of four driving data necessary for simultaneously driving four piezoelectric elements as described above.
FIG. 9A shows the phase of the high-frequency signal selected in the order of arrangement of the elements, and FIG. 9B shows the driving data sequence at that time. In this example, PAI, ZERO, Z
It is a data string that becomes ERO, PAI. Here, ZERO and PAI mean data for selecting high-frequency signals whose phases are different from each other by 180 °. The flying principle of the ink droplets when such drive data is given is as described with reference to FIGS.

Further, FIGS. 10 to 13 show examples of driving data strings when the number of simultaneously driven piezoelectric elements (the number of simultaneously driven elements) is different. 10 shows an example in which the number of simultaneous driving elements is 8, FIG. 11 shows an example in which the number of simultaneous driving elements is 10, FIG. 12 shows an example in which the number of simultaneous driving elements is 16, and FIG.

As described above, in the present embodiment, the drive data trains 54 and 64 set a drive data train composed of a set of drive data as shown in FIG.
These are stored in the drive data string buffers 55 and 65, respectively, and sequentially read out through the selectors 56 and 66, and the AND circuits 57 and 67 take the logical product with the image data to generate the drive data DRIVE DATA. Since the drive data DRIVE DATA is transferred by the shift register 44 so as to correspond to each piezoelectric element 48, a circuit for setting the drive data can have a relatively simple configuration.

In particular, as can be seen from the timing chart of FIG. 7, image data IMAGE DATA and drive data DRIVE DATA
Since the correspondence between columns is simple, when image data is read from the line memory 42, image data corresponding to pixels shifted by the number of data in the drive data column may be read. For example, when ink droplets are caused to fly by 16 piezoelectric elements as shown in FIG. 13, image data corresponding to pixels shifted by 16 pixels may be read from the line memory 42.

If this is further developed, the operation timing of FIG. 7A can be controlled as shown in the timing chart of FIG. 14, for example. That is, the reading of the image data from the line memory 42 is synchronized with the read signal READ CLOCK of the drive data sequence, and the image data is taken into the latch 52 by the load signal LOAD CLOCK of the drive data sequence. In this case, the reading of the image data from the line memory 42 is performed one pixel at a time for convenience, and the latch 52 latches the image data every four pixels. By doing so, there is no need to control the line memory 42 every four pixels, and the circuit can be further simplified.

(Another Embodiment of Driving Data Generating Unit 43 (FIG. 17)) Next, a driving method in which ink droplets are ejected at a pitch smaller than the arrangement pitch of the piezoelectric element array 2 to enable high-resolution recording. An embodiment of the data generation unit 43 will be described.

First, the principle of the present embodiment will be described with reference to FIGS. FIG. 15 is a diagram schematically showing the relationship between the position of a driven piezoelectric element and the ink droplet flying position when one or more adjacent four or five piezoelectric elements are simultaneously driven to fly one ink droplet. is there.

Here, for example, when four piezoelectric elements are simultaneously driven using the drive data shown in FIG. 16A, the ultrasonic wave is focused on the point A on the ink liquid surface and the ink liquid is moved from the point A to the ink liquid. Drops fly. On the other hand, when five piezoelectric elements are simultaneously driven using the drive data shown in FIG. 16B, the points are shifted by P / 2 (P is the arrangement pitch of the piezoelectric element array 2) from the point A on the ink liquid surface. The ultrasonic wave is focused on point B
The ink droplet flies from the point B.

As described above, when the number of piezoelectric elements driven to fly one ink droplet is even or odd, the position where the ink droplet flies depends on the arrangement pitch of the piezoelectric element array. It is shifted by 1/2 from P. The present embodiment utilizes such a principle. The principle can be referred to, for example, Japanese Patent Application No. 7-45661.

FIG. 17 is a block diagram showing a main configuration of the drive data generation unit 43 in the present embodiment. The drive data generation unit 43 of FIG. 17 is a drive data sequence generation block that generates two types of drive data sequences ZERO-DATA and PAI-DATA corresponding to two types of high-frequency signals SIGNAL ZERO and SIGNAL PAI, as in FIG. Although there is a configuration having 53, 63, these two drive data string generation blocks 53, 63
Perform the same operation with the same configuration, so only one drive data string generation block 53 will be described here.

In the present embodiment, the driving data string setting unit is 1
Two are provided for selection of one high-frequency signal. That is, the drive data string setting unit 54a is for the first flight mode in which the ink droplets fly to the first flight position, and the drive data sequence setting unit 54b is configured to transfer the ink droplets to the second flight position. This is for the second flight mode for flying. If these are made to correspond to FIG. 15, if the first flight mode is a case where an even number of piezoelectric elements are driven simultaneously, the second flight mode is a case where an odd number of piezoelectric elements are driven simultaneously. These drive data string setting units 54
FIGS. 10 and 11 show examples of the drive data strings respectively set in a and 54b.

The drive data string selection section 54c operates as a data selector, and selects the selection signal DATA SELEC from the control section 40.
One of the first and second drive data strings set in the drive data string setting units 54a and 54b by T is output to the drive data string buffer 55.

The drive data string selected by the drive data string selection unit 54c is a load signal LOAD CLOCK from the control unit 40.
Is stored in the driving data string buffer 55, and is read from the driving data string buffer 55 in synchronization with the read signal READ CLOCK. Hereinafter, the basic operation is performed according to the operation of FIG.

Next, as first and second drive data strings,
The operation will be described in detail in the case where the drive data strings shown in FIGS. 16A and 16B are used. FIG. 16A shows a drive data string for simultaneously driving four piezoelectric elements. The drive data string is composed of five data.
N is not one of the two kinds of high-frequency signals, and indicates data for deactivating the corresponding piezoelectric element. That is, although this drive data string is composed of five data, substantially only four piezoelectric elements are driven. In this case, since the drive data strings corresponding to the four driven piezoelectric elements are set to be symmetrical, the ink droplets fly at the center position (indicated by the arrow) of the four driven piezoelectric elements. Will be

FIG. 16B shows a drive data string for simultaneously driving five piezoelectric elements. Since this data string is also set to be symmetrical with respect to the left and right, the center of the five driven piezoelectric elements (indicated by an arrow). (Shown), the ink droplets fly.

As can be seen from FIGS. 16 (a) and 16 (b), in these first and second drive data strings, the flying position of the ink droplets is one with respect to the arrangement pitch of the piezoelectric element array.
/ 2.

Next, the operation of the drive data generator 43 in FIG. 17 when using these drive data strings will be described. In the drive data generation unit 43 in the present embodiment, the following three types of methods can be appropriately adopted for the selection of the drive data sequence in the drive data sequence selection unit 54c. Hereinafter, each drive data string selection method will be described.

(First Driving Data String Selection Method)
The drive data string selection method is a method in which the first and second drive data strings are alternately switched and selected for each ink droplet flying operation. FIG. 18 is an operation timing chart of the drive data generation unit 43 based on the first drive data string selection method. FIG. 19 is an arrangement of drive data set in the shift register 44 in FIG. It is the figure which showed the relationship of a position typically.

First, the first ink droplet flying operation will be described with reference to FIG. In FIG. 17, the image data of the first pixel from the line memory 42 in FIG.
2, the driving data string buffer 55
, The drive data string is read out in synchronization with the read signal READ CLOCK. At this time, the drive data string read from the drive data string buffer 55
a selection signal DATA SEL from the control unit 40
This is the first drive data string selected by the drive data string selection unit 54c according to ECT. This first drive data string is for simultaneously driving four adjacent piezoelectric elements as shown in FIG.
(MODE1) drive data string.

While sequentially reading out the drive data sequence in this way, the AND circuit 57 calculates the logical product with the image data of the first pixel, and outputs this to the shift register 44 as drive data. Shift data of 5 drive data to shift register 4
4, the load signal LOAD CLO from the control unit 40 is output.
The driving data string of mode 1 is set again in the driving data string buffer 55 by the CK from the driving data string setting unit 54a. At the same time, the image data of the eleventh pixel is fetched from the line memory 42 into the latch 52, and the drive data train of mode 1 is sequentially read out from the drive data train buffer 55 in synchronization with the read signal READ CLOCK. Drive data corresponding to the piezoelectric element is generated. Similarly, 21
The image data of the pixel is taken into the latch 52, and the five drive data are output to the shift register 44.

When such operation is repeated and all 4960 drive data per line are transferred to the shift register 44, similar to the operation timing shown in FIG.
Drive data is taken into the latch 45 by the latch signal LATCH CLOCK from the shift register 44, and each piezoelectric element is driven based on the drive data taken into the latch 45. Thus, the first ink droplet flying operation is completed.

Here, the operation of FIG. 18 is significantly different from the operation of FIG. 7 in that the image data read out from the line memory 42 is every ten pixels, but this is composed of five drive data. This is due to the use of two types of drive data strings.

Next, the second ink droplet flying operation will be described with reference to FIG.

In this case, similar to the first flight operation,
At the same time when the image data of the second pixel is taken into the latch 52, the drive data string is read out from the drive data string buffer 55 in synchronization with the read signal READ CLOCK. At this time, the drive data string read from the drive data string buffer 55 is set by the drive data string setting unit 54b, and the first drive data selected by the drive data string selection unit 54c according to the selection signal DATA SELECT from the control unit 40. Column. This second drive data string is for simultaneously driving five adjacent piezoelectric elements as shown in FIG. 16B, and this is called a mode 2 (MODE2) drive data string. I do.

In this way, five drive data corresponding to the image data of the second pixel are generated, and the shift register 44
, The process proceeds to the processing of the image data of the twelfth pixel. In this case, five drive data are generated in the same manner, and the processing shifts to processing of the image data of the 22nd pixel. All the drive data is transferred to the shift register 44, and the second ink droplet flying operation is performed.

Next, the third ink droplet flying operation will be described with reference to FIG. 18C. The generation of drive data for the third flying operation is the same as that in the first flying operation. Thus, the driving data string of mode 1 is selected. Similarly, during the fourth flying operation, the driving data string of mode 2 is selected, and thereafter, the driving data strings of mode 1 and mode 2 are alternately selected for each flying operation of the ink droplets. Such selection switching of the drive data string is performed by a signal from the control unit 40. As described above,
In the present embodiment, the ink droplet flying operation is performed ten times for one line of the recording operation.

FIG. 19 is a diagram showing the relationship between the arrangement of drive data set in the shift register 44 and the flying position at that time during these ten ink droplet flying operations. In FIG. 19, the driving data strings of mode 1 are arranged in order of A, B,
C, D, and E, the drive data strings of mode 2 are arranged in the order of a, b, c, d, and e, and the first drive data corresponding to the image data of the nth pixel is described as nA or na. Further, the flying positions of the ink droplets are indicated by arrows in the figure. For example, in the first flight operation, drive data 1B and 1
This indicates that the ink droplet flies at the intermediate position of C, and that the ink droplet flies at the position of the drive data 2c in the second flying operation.

As is clear from this, 10 times from the first time
In the first flying operation, the flying position of the ink droplet is operated so as to be shifted by の of the arrangement pitch of the piezoelectric element array 2 each time. It should be noted that data with parentheses, such as drive data (1E), indicates that the corresponding piezoelectric element is not driven, and the symbol W in the drawing is data that does not drive the high-frequency signal. That there is
These are made by the operation of the selector 56 as described with reference to FIG.

The above-described first drive data string selection method is as follows.
This is a method in which two driving data strings are switched and selected for each flying operation of ink droplets. With a simple circuit configuration, it is possible to realize high-resolution recording that is equal to or more than the arrangement pitch of the piezoelectric element array. Since the relationship with the flying position of the ink droplet is simple, the method of reading the image data from the line memory 42 can be simplified, and the flying position of the ink droplet can be set to a predetermined value in any flying operation. Since they are arranged at intervals, there is an advantage that the recording operation can be stabilized.

(Second Driving Data String Selection Method) In the second driving data string selection method, a first driving data string (a driving data string in mode 1) is used in one flying operation of an ink droplet.
And the second drive data string (the drive data string of mode 2) are mixed, in other words, the drive data string is alternately switched and selected in the arrangement order. 20 and 21
Shows an example in which two drive data strings are alternately switched and selected in the order in which adjacent drive data strings are arranged. FIG.
FIG. 21 shows the operation timing, and FIG. 21 shows the relationship between the arrangement order of the drive data and the flying positions of the ink droplets.

According to FIG. 20, in the first ink droplet flying operation, five driving data corresponding to the image data of the first pixel is generated by using the driving data string of mode 1;
Next, five drive data corresponding to the image data of the twelfth pixel is generated using the drive data string of mode 2. That is, the driving data sequence is generated by alternately switching and selecting the driving data sequence. For the second and subsequent ink droplet flying operations, drive data is generated by the same operation.

The difference from the case of FIG. 18 is that the read order of the image data is different in addition to the point that the drive data string is switched for each image data. That is, at the time of the first ink droplet flying operation, the image data is processed in the order of the first pixel, the twelfth pixel, the twenty-first pixel,.
The processing is performed in the order of the first pixel, the 22nd pixel, and so on. As can be seen from FIG. 21, the flying positions corresponding to the image data of the even-numbered pixels are alternately shifted in each ink droplet flying operation. However, when the ink droplet flying operation of ten times is completed, it operates correctly as a one-line recording operation.

As described above, according to the second driving data string selection method, the driving data strings are alternately switched in the order of the driving data strings, and the driving data string of the mode 1 and the driving data string of the mode 2 are changed in one flying operation of the ink droplet. This is a method in which drive data strings are mixed and selected. Since there is always drive data for non-drive of the piezoelectric element in each ink droplet flying operation, for example, drive data (1E), the maximum simultaneous drive piezoelectric element is provided. The number can be reduced. Therefore, there is an advantage that the power supply capacity of the drive circuit can be reduced.
Furthermore, since non-drive data can be provided at regular intervals in the arrangement direction of the piezoelectric elements, there is an advantage that mutual interference of the flying of ink droplets from each group can be prevented and the flying operation can be stabilized. There is also.

(Third drive data string selection method) In the third drive data string selection method, two drive data strings of mode 1 and mode 2 are used in the first half and the second half of the ink droplet flying operation period in one line. This is a method of switching and selecting, as shown in FIG.
This will be specifically described with reference to FIGS. 22 and 23 show the operation timing, and FIG. 24 shows the relationship between the arrangement order of the drive data and the flying positions of the ink droplets.

In this example, one line of recording operation is performed by ten ink droplet flying operations. However, for the first five flying operations, drive data is generated by using a drive data string of mode 1, and For the last five flight operations, drive data is generated using the drive data string of mode 2. FIG.
(A), (b), and (c) show the operation of the drive data generator 43 during the first, second, and third ink droplet flying operations, respectively, of the one-line printing operation. That is,
The driving data string of mode 1 is repeatedly read out for the first ink droplet flying operation, and the first pixel, the eleventh pixel,
Driving data corresponding to the image data of the 21st pixel is generated. The same applies to the second and subsequent ink droplet flying operations.

FIGS. 23D, 23E, and 23F show 6
The operation timing of drive data generation at the time of the seventh, seventh, and eighth flight operations is shown. By generating the drive data using the drive data string of mode 2, as shown in FIG. 24, for the first half to five flight operations,
The operation is performed such that the flying position is shifted by の of the arrangement pitch of the piezoelectric element array.

As described above, in the third drive data string selection method, the ink droplets are ejected to a position different from the mode 1 in the period in which the ink droplet flying operation by the drive data string in mode 1 is performed during the recording period of one line. By separating the period from the period in which the ink droplet flying operation is performed by the driving data string in Mode 2 to be performed, the flying position (landing position) of the ink droplet shifts by one pixel in the continuous flying operation. Therefore, for example, in the second drive data string selection method described with reference to FIG.
While there is only a shift of two pixels, in the third drive data string selection method, the flying position of the ink droplet is further reduced by 1 /
Since there is a separation of two pixels, there is an advantage that bleeding of ink droplets after landing on recording paper can be prevented.

By using any one of the three drive data string selection methods described above to select and switch different drive data strings, the arrangement pitch of the piezoelectric element array can be reduced with a relatively simple configuration. In this manner, ink droplets can fly at half the pitch, and higher-resolution recording can be performed without increasing the arrangement pitch of the piezoelectric element array. In addition, by utilizing the difference in merit due to the difference in the drive data string selection method described above, these methods can be selectively used.

In the above description, the mode in which four piezoelectric elements are driven simultaneously is mode 1, and the mode in which five piezoelectric elements are driven simultaneously is mode 2. However, the present invention relates to the number of simultaneously driven piezoelectric elements. It is not limited. That is, as shown in, for example, FIGS. 10, 11, and 12, the number of simultaneously driven elements can be changed and applied in various ways such as 8 and 9 elements or 9 and 10 elements.

FIG. 25, FIG. 26, FIG. 27, and FIG. 28 show other examples of the drive data sequence. That is, FIG.
This is an example of a driving data string for driving nine piezoelectric elements simultaneously by including non-driving data, which is composed of zero data. 26 to 28
This is an example of a drive data sequence for simultaneously driving substantially ten piezoelectric elements by including non-drive data, which is composed of 16 data.

As described above, by appropriately including the non-drive data in the drive data train, the flight intervals of the ink droplets to be simultaneously fly can be increased, and the flight operation can be stabilized. Furthermore, even if the number of elements to be driven is substantially different between mode 1 and mode 2 as shown in FIG. 16, the operation is performed with a simpler configuration as described above by treating them as drive data strings having the same number of data. Can be done.

In the above description, two phases of high-frequency signals SIGNAL ZERO and SIGNAL PAI having different driving data corresponding to each piezoelectric element are used as a driving data string for driving the piezoelectric element.
Was mentioned. Specifically, the phase of another high-frequency signal SIGNAL PAI is shifted by 180 ° with reference to the phase of one high-frequency signal SIGNAL ZERO. However, the drive data sequence in the present invention does not necessarily need to be data having such a phase relationship, and the drive data in which the phase of the other high-frequency signal is shifted by 90 ° with respect to one of the two types of high-frequency signals. Columns can also be used. In this case, for example, the driving data sequence may be set in the same manner as the driving data sequence shown in FIG.

Also, using only one of the two high-frequency signals, the high-frequency signal SIGNAL ZERO, generates the high-frequency signal SIGNAL ZERO.
A configuration that does not use AL PAI can also be used. Also in this case, ink droplets can be made to fly by appropriately selecting the drive data string. In the generation of the drive data in this case, for example, the high-frequency signal SIGNALZE in FIG.
The configuration may be such that only drive data ZERO-DATA for selecting RO is generated. In this case, the overall configuration of the driving circuit 3 can be simplified, for example, so that the shift register 44 and the latch 45 in FIG. 4 handle 1-bit data. Only the high-frequency signal SIGNAL ZERO may be output, and the selector 46 may select the high-frequency signal SIGNAL ZERO according to ON / OFF of the drive data ZERO-DATA.

Further, three kinds of high-frequency signals can be used as data constituting the drive data train. FIG.
Reference numeral 9 denotes an example of a drive data string including five data when three types of high-frequency signals are used. In this example, three kinds of high-frequency signals SIGNAL ZERO, SIGNAL PAI and SIGNAL PAI
2 is used. High-frequency signal SIGNAL PAI is 180 °, high-frequency signal SIGN based on high-frequency signal SIGNAL ZERO
AL PAI2 90 ° out of phase.

In this case, the driving data string is the first data string
It is composed of DATA1 and a second data string DATA2. A drive data generation unit using such a drive data sequence can be configured, for example, as shown in FIG. Drive data in FIG.
Drive data string buffer 54 for generating ZERO-DATA
The first data string DATA1 is stored in the drive data string buffer 64 for generating the drive data PAI-DATA.
What is necessary is just to set it as the structure which sets DATA2 respectively. The overall configuration of the drive circuit 3 in this case is such that, for example, three types of high-frequency signals are generated from the high-frequency signal generator 41 in FIG. 4, and the selector 46 selects a high-frequency signal based on a truth table shown in FIG. The configuration may be such that the data is output to the side.

By employing such a configuration using three types of high-frequency signals, the number of high-frequency signals to be prepared increases and the handling becomes slightly complicated, but smooth sound is generated by the ultrasonic waves generated from the individual piezoelectric elements. There is an advantage that a field can be formed and the flight stability of the ink droplet is further improved.

[0113]

As described above, according to the present invention, a plurality of predetermined sound wave generating elements in the sound wave generating element array are grouped into one group, and each sound wave generating element in this group is driven according to image data. In an ink jet printing apparatus that performs printing by flying ink droplets for each group by driving individually and substantially simultaneously according to data, a drive consisting of a set of drive data for driving each sound wave generating element in the group A driving data string buffer for storing a data string is provided, and the driving data strings stored in the driving data string buffer are sequentially read out corresponding to each sound wave generating element in the group and repeatedly read out corresponding to each group, and the image is read out. By performing a logical AND operation with the data, drive data corresponding to the image data is generated, and the generated drive data is output to, for example, a system. Sequentially by transfer to and configured to drive the individual ultrasound generating element with Torejisuta, without requiring a complicated circuit or a complicated process, it is possible to realize a linear electronic scanning operation with a relatively simple configuration.

According to the present invention, a set of drive data for driving each sound wave generating element in a group is provided.
In addition, first and second drive data strings set so as to cause ink droplets to fly to different positions are prepared, for example, in a drive data string buffer, and one of these drive data strings is selected. By performing a logical AND operation of the selected drive data sequence and the image data, drive data corresponding to the image data is generated, and the generated drive data is sequentially transferred by, for example, a shift register to drive each sound wave generating element. With this configuration, ink droplets can be made to fly at an interval smaller than the arrangement pitch of the sound wave generating element array with a relatively simple configuration. That is, higher-resolution recording can be realized without increasing the arrangement pitch of the sound wave generating element arrays.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a view for explaining the recording principle of the ink jet recording apparatus.

FIG. 3 is a diagram illustrating a driving method of the ink jet recording apparatus.

FIG. 4 is a block diagram showing an embodiment of a drive circuit in the inkjet recording apparatus.

FIG. 5 is a block diagram illustrating a configuration according to an embodiment of a drive data generation unit in FIG. 4;

FIG. 6 is a timing chart for explaining the operation of the drive circuit of FIG. 4;

FIG. 7 is a timing chart for explaining the operation of the drive data generation unit in FIG. 5;

FIG. 8 is a diagram showing a truth table for explaining drive data and drive phases;

FIG. 9 is a diagram showing an example of a driving data sequence.

FIG. 10 is a diagram showing another example of a drive data string.

FIG. 11 is a diagram showing still another example of a drive data string.

FIG. 12 is a diagram showing still another example of a drive data string.

FIG. 13 is a diagram showing still another example of a drive data string.

14 is another timing chart for explaining the operation of the drive data generation unit in FIG.

FIG. 15 is a diagram for explaining the relationship between the number of driven elements of the piezoelectric element array and the ink droplet flying position.

FIG. 16 shows first and second ink droplets in different flight modes.
Showing an example of the drive data sequence

FIG. 17 is a block diagram showing a configuration according to another embodiment of the drive data generation unit in FIG. 4;

FIG. 18 in the first drive data string selection method
Timing chart for explaining the operation of the driving data generator of FIG.

FIG. 19 is a view for explaining an arrangement of drive data and a flying position of an ink droplet in the first drive data string selection method.

FIG. 20 shows the second drive data string selection method in FIG.
Timing chart for explaining the operation of the driving data generator of FIG.

FIG. 21 is a diagram for explaining an arrangement of drive data and a flying position of an ink droplet.

FIG. 22 shows the second drive data string selection method in FIG.
Timing chart for explaining the operation of the driving data generator of FIG.

FIG. 23 illustrates a third drive data string selection method in FIG.
Timing chart for explaining the operation of the driving data generator of FIG.

FIG. 24 is a diagram for explaining an arrangement of drive data and a flying position of an ink droplet in a third drive data string selection method.

FIG. 25 is a diagram showing another example of the driving data sequence.

FIG. 26 is a diagram showing another example of the driving data sequence.

FIG. 27 is a diagram showing another example of the driving data sequence.

FIG. 28 is a diagram showing another example of the driving data sequence.

FIG. 29 is a diagram showing an example of a drive data string for selecting three types of high-frequency signals.

FIG. 30 is a diagram showing a truth table for selecting three types of high-frequency signals.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Glass plate 2 ... Sound generation source 3 ... Drive circuit 4 ... Nozzle substrate 5 ... Ink chamber 6 ... Nozzle hole 7 ... Fresnel diffraction band plate 40 ... Control unit 41 ... High frequency signal generation unit 42 ... Line memory 43 ... Drive data generation Unit 44 shift register 45 latch 46 selector 47 driver 48 piezoelectric element 52 latch 54, 64 drive data string setting unit 54c, 64c drive data string selection unit 55, 65 drive data string buffers 56, 66 ... Selectors 57, 67 ... AND circuit

Claims (9)

[Claims] A plurality of predetermined sound wave generating elements in a sound wave generating element array are grouped into one group, and each sound wave generating element in the group is individually and substantially simultaneously driven in accordance with drive data corresponding to image data. An ink jet recording apparatus that performs recording by flying ink droplets for each group; and a driving data column buffer that stores a driving data column including a set of driving data for driving each sound wave generating element in the group. Reading out the driving data sequence stored in the driving data sequence buffer sequentially and repeatedly corresponding to each sound wave generating element in the group, and performing an AND operation with the image data. And a drive data generating means for generating drive data corresponding to the image data by the Door recording device. 2. The ink jet recording apparatus according to claim 1, wherein the drive data sequence is data indicating a phase of drive data corresponding to each sound wave generating element in the group. 3. A method according to claim 1, wherein a plurality of predetermined sound wave generating elements in the sound wave generating element array are grouped into one group, and each sound wave generating element in the group is individually and substantially simultaneously driven according to drive data corresponding to image data. An ink jet recording apparatus for performing recording by flying ink droplets for each group, comprising a set of drive data for driving each sound wave generating element in the group, and flying the ink droplets to different positions. Driving data string selecting means for selecting one of the first and second driving data strings set to be driven, a driving data string selected by the driving data string selecting means, and the image data Drive data generating means for generating drive data according to the image data by performing a logical AND operation with An ink jet recording apparatus characterized. 4. A plurality of predetermined sound wave generating elements in a sound wave generating element array are grouped into one group, and each sound wave generating element in the group is individually and substantially simultaneously driven according to drive data corresponding to image data. An ink jet recording apparatus for performing recording by flying ink droplets for each group, comprising a set of drive data for driving each sound wave generating element in the group, and flying the ink droplets to different positions. Driving data string selecting means for selecting one of the first and second driving data strings set to be driven, and driving for storing the driving data string selected by the driving data string selecting means A data string buffer, and a drive data string stored in the drive data string buffer corresponding to each sound wave generating element in the group. An ink-jet recording apparatus comprising: a driving data generation unit that sequentially reads out and repeatedly corresponds to each group, and performs a logical product operation with the image data to generate driving data according to the image data. Recording device. 5. The ink jet printer according to claim 3, wherein the first and second drive data strings are data indicating a phase of drive data corresponding to each sound wave generating element in the group. Recording device. 6. The apparatus according to claim 3, wherein at least one of said first and second drive data strings includes at least one non-drive data for deactivating a corresponding sound wave generating element. The inkjet recording apparatus according to any one of the above items. 7. The driving data sequence selecting means alternately switches and selects the first and second driving data sequences for every flying operation of an ink droplet.
The inkjet recording apparatus according to any one of the preceding claims. 8. The driving data string selecting means according to claim 3, wherein the first and second driving data strings are mixed and selected in one flying operation of the ink droplet. Ink jet recording device. 9. The driving data sequence selecting means according to claim 1, wherein the first and second half of a series of ink droplet flying operation periods in one line are first.
5. The ink jet recording apparatus according to claim 3, wherein the second drive data sequence is switched and selected.