JPH0920005A - Inkjet printer - Google Patents

Abstract

(57) Abstract: Since dots that could not be formed by the first printing operation are formed by the second printing operation, it is necessary to form one line of character by two printing operations. It was very difficult to speed up. In a preceding cycle of repetition, an ink ejection nozzle selected every other first ink ejection nozzle array is ejected by a first ejection control unit according to dot array data representing a character. Then, in the subsequent cycle of the repetition, the ink ejection nozzles selected at every other second ink ejection nozzles and at a position different from the ink ejection nozzles selected at every other arrangement of the first ink ejection nozzles. By controlling the ejection of the nozzles by the second ejection control means according to the data of the dot arrangement for expressing the character, the nozzles of the first arrangement of the ink ejecting nozzles,
A character is expressed by a combination of a dot array of ejected ink with a nozzle of the second array of ink ejecting nozzles.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet printer, and more particularly to an inkjet printer that can operate at high speed.

[0002]

2. Description of the Related Art FIG. 16 is a partially exploded perspective view of a typical example of a print head of a conventional ink jet printer.

Referring to FIG. 16, a print head of a conventional ink jet printer is made of a piezoelectric material and has an upper surface similar to the ink chamber base 102 having grooves formed by a plurality of comb-shaped side walls 122. An ink chamber cover block 104, which is made of a piezoelectric material, has a plurality of comb-shaped grooves on the lower surface, and is fixed so that the lower surface is in contact with the upper surface of the ink chamber base 102, the ink chamber base 102, and the ink chamber cover. Side wall electrode 1 provided on the wall surface in each ink chamber 106 formed by each groove with block 104
08, an orifice plate 116 that covers the end surfaces of the ink chamber base 102 and the ink chamber cover block 104 on the side where the ink chamber 106 is open, and the ink chamber base 1
And a driving integrated circuit (hereinafter referred to as “driving IC”) 110 for applying a predetermined voltage to each sidewall electrode 108, which is provided in a portion where the groove of the upper surface of 02 is not formed. The driving IC 110 is connected to an external control circuit (not shown) by an input wiring 112, and is connected to each sidewall electrode 108 by a driving wiring pattern 114.

A nozzle orifice 118 from which ink is ejected is provided at a position of the orifice plate 116 corresponding to the center of the opening of each ink chamber 106.
Each ink chamber 106 is provided in the ink chamber cover block 104.
A plurality of ink introduction holes 12 for supplying ink for each
0 is provided.

FIG. 17A is an enlarged sectional view of the side wall 122. The side wall 122 is the ink chamber base 102 made of a piezoelectric material.
It is also part of, and is also piezoelectric. Separate sidewall electrodes 108a and 108b are provided on both side surfaces of the sidewall 122, respectively. The side wall 122 is polarized in the direction indicated by arrow D in FIG.

A positive voltage is applied to the side wall electrode 108a and a negative voltage is applied to the side wall electrode 108b. Side wall 122
Is polarized. Therefore, as shown in FIG. 17B, the side wall 122 undergoes shear deformation due to the inverse piezoelectric effect. This phenomenon is called the piezoelectric shear mode effect. Each side wall on the lower surface of the ink chamber cover block 104 is polarized on the side opposite to the arrow D.

FIG. 18 is a sectional view taken along line XVI-XVI in FIG. FIG. 18 shows the state of the print head during operation. It should be noted that only five ink chambers 106 are drawn in FIG. 16 for simplification of the drawing. In the actual print head, FIG.
As shown in FIG.
b, 106c, 106d ... Are provided.

The operation of the print head of the conventional ink jet printer will be described with reference to FIGS. The ink chamber 106 is filled with the ink supplied from the ink introduction hole 120. The driving IC 110 applies a predetermined voltage to each of the side wall electrodes 108 according to the dot pattern of the print data. The side walls provided in each of the ink chamber block 102 and the ink chamber cover block 104 undergo shear deformation according to the voltage applied to the side wall electrode 108.

The cross-sectional shape of each ink chamber 106 changes due to the deformation of the side wall. The pressure rises in the ink chamber 106 where both side walls are deformed inward and the cross-sectional area thereof is reduced.
Therefore, ink is ejected from the nozzle orifice 118. No ink is ejected from the other ink chambers.

In FIG. 18, side wall electrodes 108a, 108
No voltage is applied to b. Side wall electrode 108c, 1
A positive voltage is applied to 08e. Side wall electrode 1
A negative voltage is applied to 08d and 108f. Among the side walls, the side walls 122c, 122d, 122e, 122f and the like having potential differences between the side wall electrodes on both surfaces thereof are deformed as shown in FIG. After that, the side walls 122c and 122e and the side walls 122d and 122f are
Since the plus and minus of the voltage applied to the side wall electrodes on both sides thereof are opposite, deformation occurs in the opposite direction.

Due to the shearing deformation of the side wall as described above, the areas of the ink chambers 106d and 106f are reduced, and ink is ejected from these ink chambers. No ink is ejected from the other ink chambers. As a result, a vertical length of 1 is printed on the recording paper placed near the orifice plate 116 of the print head.
A set of dots for columns is formed. The print head moves in a direction orthogonal to the arrangement direction of the ink chambers 106 to form the next set of dots for one vertical column.

The above operation is repeated to form a character as a set of dots on the recording paper.

[0013]

However, the conventional ink jet printer has a problem that it is difficult to increase the printing speed without increasing the manufacturing cost. As shown in FIG. 18, adjacent ink chambers share a side wall. Therefore, it is impossible to eject ink simultaneously from the adjacent ink chambers. Therefore, dot recording is performed by alternately driving every other ink chamber.
For example, first, odd-numbered ink chambers are driven, and then even-numbered ink chambers are driven. That is, printing of dots for one row of nozzles is completed by the printing operation of two cycles.

In this case, the relative positional relationship between the recording paper and the print head must not be changed until the 2-cycle recording operation is completed. Otherwise, the dots that should be arranged in one row will be dispersed in two or more rows. In the serial printer, it is possible to stop the relative movement between the print head and the recording paper during the two-cycle recording operation as described above.
Practically impossible. Further, also in the line printer, the above operation is a major obstacle to speeding up.

In order to avoid the above-mentioned difficulties in the serial printer, the following method can be considered. That is, the first recording operation is performed over one line while moving the print head and the recording paper relatively. Next, another recording operation is performed on the same line on the recording paper. And one
Dots that could not be printed by the second printing operation are formed by the second printing operation. That is, in this case, a complete array of dots is formed by two recording operations.

However, according to this method, one line becomes 2
Since it is necessary to record by one printing operation, it is naturally difficult to speed up printing.

Further, the nozzle array of the print head is lengthened,
A method of speeding up printing is also conceivable. However, for that purpose, the size of the head must be increased.
Further, if the data to be printed at one time extends over a plurality of lines, a much larger number of data buffers are required to temporarily store the data when printing. Therefore, the inkjet printer having such a mechanism is disadvantageous in cost.

Therefore, an object of the present invention is to provide an ink jet printer capable of speeding up printing without increasing the cost.

[0019]

An ink jet printer according to the present invention includes an array of a plurality of aligned and individually controllable ink jet nozzles, and is arranged in a direction intersecting with an object to be recorded. An ink jet printer in which a character is represented as a dot array of ejected ink in an alignment direction and a cross direction by individually controlling ejection of ink while performing relative displacement between the ink ejection nozzles. The array includes an array of first ink ejecting nozzles and an array of second ink ejecting nozzles arranged side by side.

In the ink jet printer according to the present invention, in the preceding cycle of repetition, the ejection control of the ink ejection nozzles selected every other arrangement of the first ink ejection nozzles is performed according to the data of the dot arrangement expressing the character. And a second ink ejection nozzle selected in every other second ink ejection nozzle array and in every other array of first ink ejection nozzles in subsequent cycles of repetition. And a second ejection control unit that controls ejection of ink ejection nozzles at positions different from that in accordance with dot array data that should represent a character.

The first ejection control means ejects the ink ejection nozzles selected every other arrangement of the first ink ejection nozzles according to the data of the dot arrangement for expressing the character in the preceding cycle of repetition. Control.

The second ejection control means is selected every other second ink ejection nozzle in the subsequent cycle of the repetition, and is selected in the preceding cycle of the arrangement of the first ink ejection nozzles. The ink ejection nozzles at positions different from the ink ejection nozzles are ejection-controlled in accordance with the dot array data that should represent the character.

A character is represented by a combination of dot arrays of ejected ink of the nozzles of the first array of ink ejection nozzles and the nozzles of the array of second ink ejection nozzles.

[0024]

1 is a perspective view of a print head of an ink jet printer according to an embodiment of the present invention. FIG.
FIG. 3 is an exploded perspective view of the print head shown in FIG. 1.

Referring to FIGS. 1 and 2, the print head includes a first multi-nozzle head 10 having a first ink jet nozzle array and a first multi-nozzle head 10.
A second multi-nozzle head 12 fixed to the back surface of the first ink jet nozzle and having a second array of ink jet nozzles;
An orifice plate 14 is fixed to the first multi-nozzle head 10 and the second multi-nozzle head 12 so as to cover the above ink jet nozzle array.

The first multi-nozzle head 10 has a plurality of grooves formed by separating a plurality of comb-shaped side walls 13, and a first ink chamber base 16 made of a piezoelectric material such as piezoelectric ceramics. A groove having the same shape as the groove formed in the first ink chamber base 16 is formed on the lower surface, is fixed to the upper surface of the first ink chamber base 16, and is a first ink chamber cover block made of piezoelectric ceramics or the like. 18 and.
The grooves of the first ink chamber base 16 and the grooves of the first ink chamber cover block 18 form a plurality of ink chambers 33.

The first multi-nozzle head 10 further includes
Side wall electrodes 20 provided in each ink chamber 33 and formed of a conductive thin film that covers both side walls of each ink chamber 33 and the bottom surface of each ink chamber 33 on the first ink chamber base 16 side.
A first driving IC 22 fixed to the first ink chamber base 16 for applying a voltage for driving the first ink ejection nozzle array to the side wall electrode 20; and an external circuit (not shown). Input wiring 24 for connecting the first driving IC 22, first driving IC 22 and each electrode 2
Drive wiring pattern 26 for connecting with 0.

The second multi-nozzle head 12 also has a structure similar to that of the first multi-nozzle head 10. The second multi-nozzle head 12 includes a second ink chamber base 28 made of piezoelectric ceramics and the like, and a second ink chamber base 2
A second ink chamber cover block 30 made of piezoelectric ceramics or the like, which is fixed to the lower surface of 8 and forms a plurality of ink chambers 34 with the second ink chamber base 28, and is provided in each ink chamber 34. Side electrode 32 made of a conductive thin film
And a second drive IC (not shown) for applying a drive voltage to the sidewall electrode 32 and a necessary wiring pattern.

The orifice plate 14 is provided in each ink chamber 3
Nozzle orifices 38 are provided at locations corresponding to the center of the cross section of the openings 3 and 34, respectively.

On the surfaces of the first ink chamber cover block 18 and the second ink chamber cover block 30 opposite to the ink chambers, ink introducing holes 36 for supplying ink to the ink chambers 33 and 34 are provided. It is provided. However, the ink introduction hole 36 of the second ink chamber cover block 30 is not shown.

FIG. 3A is a view in the direction of arrow IIIA-IIIA in FIG. 1, and is a plan view of the orifice plate 14.

With reference to FIG. 3A, the orifice plate 14 has an A-row nozzle group indicated by arrow A and a B-row nozzle group indicated by arrow B. The print head is shown in Figure 3.
In (A), the recording paper is moved in the direction indicated by arrow D.

FIG. 3B is a sectional view taken along the line IIIB-IIIB of FIG. 1 and shows a cross section of the ink chambers 33 and 34. FIG.
Referring to (B), this print head has a row A ink chamber group corresponding to the row A nozzle group and a row B ink chamber group corresponding to the row B nozzle group.

Referring to FIG. 3B, each ink chamber 33,
The piezoelectric ceramic forming the side wall of 34 is polarized in the direction indicated by the small arrow in the figure.

In FIG. 3A, when the distance between the A-row nozzle group and the B-row nozzle group is represented by l, l is calculated by the following equation.

L = N × d However, N is an arbitrary natural number, and d is an interval between dots to be recorded (hereinafter referred to as “basic dot pitch”).

The basic dot pitch d is shown in FIG. In FIG. 3, an arrow D indicates the moving direction of the print head. There is a slight difference in the driving method of each ink ejecting nozzle between when N is even and when N is odd. For this embodiment, N shall be an odd number.

The operation of the print head will be described with reference to FIGS. 1 to 3B. The drive IC 22 and the drive IC (not shown) respond to print information sent from the outside, via the drive wiring pattern 26, the side wall electrodes 20,
A predetermined voltage is applied to 32.

When a voltage is applied to each sidewall electrode 20, 32, shear deformation due to the inverse piezoelectric effect occurs in the piezoelectric ceramics constituting the sidewall, as described in the section of the prior art. This is shown in FIG.

With reference to FIG. 5, each of the ink chamber group in the A row and the ink chamber group in the B row is driven similarly to the ink chamber group in the conventional technique. That is, the side walls 13 and 15 to which a predetermined potential difference is applied between the side wall electrodes on both sides cause shear deformation in the direction corresponding to the polarization direction. Ink chamber 3
Of the parts 3, 34, the ones whose both side walls are deformed inward have a reduced volume. Ink chamber 3 with reduced volume
The insides of the ink cartridges 3 and 34 are filled with the ink previously supplied from the ink introducing hole 36. Therefore, the pressure inside the ink chambers 33 and 34 whose volumes have decreased increases, and ink is ejected from the nozzle orifice 33.

As is clear from FIG. 5 and as described in the section of the prior art, each ink chamber 33, 34 shares a side wall with an adjacent ink chamber, and therefore can be driven only every other ink chamber. Therefore, every other ink chamber in the row A nozzle group and the row B nozzle group are alternately driven.

FIG. 6A shows how ink is ejected from the odd-numbered ink ejection nozzles in both the A-row nozzle group and the B-row nozzle group. Similarly, FIG. 6B shows how ink is ejected from the even-numbered ink ejecting nozzles. FIG.
Among the nozzle orifices 38 shown in (A) and FIG. 6 (B), the hatched nozzle orifice 38 is capable of ejecting ink.

Ink ejected from each nozzle of the row B and each nozzle of the row A by moving the print head in the direction of the arrow D while alternately repeating the operations of FIGS. 6A and 6B. Thus, a character is formed as a set of dots.

FIGS. 7A to 7C are schematic diagrams of dot arrangement on the recording paper showing a state of dot formation when N = 5.

With reference to FIG. 7 (A), the nozzle group of row B forms dots prior to the nozzle group of row A.
An odd-numbered dot group formed by the B-row nozzle group at a certain time point is a Bl row, and an odd-numbered dot group formed by the A-row nozzle group is an A1 row. The interval between the B1 row and the A1 row is 5d where the basic dot pitch is d. Between the A1 row and the Bl row, there is already a dot group formed by the B row nozzle group.

FIG. 7B shows the dot arrangement when the print head advances by d in the direction of arrow D. Figure 7
Referring to (B), an even-numbered dot group formed by the B-row nozzle group is defined as B2 row, and an even-numbered dot group formed by the A-row nozzle group is defined as A2 row.

The B2 row is d from the Bl row in the direction of the arrow D.
Just ahead. Similarly, column A2 is A in the direction of arrow D.
There is d ahead of row 1. At the same time, in the row A2, among the one dot row formed by the row B nozzle group, the blank portion where no dots are formed is filled with dots. That is, the recording operation by the A nozzle group is added to the recording operation by the B nozzle group to form one complete dot row.

The print head is further moved in the direction of arrow D by a distance d.
Figure 7 shows the state of the dot group when it is moved
(C). Referring to FIG. 7C, the row B nozzle group forms an odd-numbered dot group B3 row, and the row A nozzle group forms an odd-numbered dot group A3 row. The dot row of this row is completed by forming the odd-numbered dot group of the A3 row. By repeating the above-described operation, characters as an array of dots are formed on the recording paper.

FIG. 8 is a plan view of the orifice plate 14 showing a general arrangement of nozzle orifices of the ink jet nozzle according to the present invention. With reference to FIG. 8, the orifice plate 14 is provided with 2n nozzle orifices 38a in row A and 2n nozzle orifices 38b in row B. Every other nozzle in each row is driven alternately.

FIG. 9 is a schematic plan view showing a dot array on the recording paper formed by the array of nozzle orifices shown in FIG. In FIG. 9, the dots are represented as a matrix. The uppermost dot at the left end of Fig. 9 is D
It is expressed as (1, 1), and the dot in the i-th row and the j-th column is D (i,
j). However, 1 ≦ i ≦ 2n.

In FIG. 8, there is a distance l = N between columns A and B.
Only xd apart. N is an arbitrary odd number, and d represents a basic dot pitch.

FIGS. 10A and 10B are timing charts showing the print timings of the B-row nozzle group and the A-row nozzle group and the dots to be printed, respectively. FIG.
In (A) and FIG. 10 (B), k represents an arbitrary integer of 1 or more and n or less, and j represents the row number of the dot recorded by the B row nozzle group at time t ₀ . However, FIG.
In (B), when j is equal to or less than N, the recording operation of the column A is not performed.

The maximum number of times that one nozzle can eject ink in one second is called the maximum frequency and is represented by f _MAX . t ₀ is equal to the reciprocal of f _MAX . t ₀ represents the shortest value of the time interval of ink ejection from the nozzle.

Referring to FIGS. 10A and 10B, when the time t = t ₀ , the B-row nozzle group selects each D (2k−1, j) dot in the dot matrix. I am recording. That is, of the nozzles of the B-row nozzle group, only the odd-numbered nozzles can print dots. on the other hand,
At this time, the row A nozzle group has a dot matrix of D (2k−
, 1, j-N). That is, only the odd-numbered nozzles of the nozzles of the row A nozzle group can perform dot recording. However, it should be noted that the row A nozzle group is behind the row B nozzle group by l (= N × d).

[0055] When the time has elapsed t _0/2, in the B column nozzle group D (2k, j + 1) (k = l, 2, ...,
The recording operation of the dot group of n) is performed. That is, only the even-numbered dots in the dot row one row ahead of the last time are recorded. Similarly, only the even-numbered dots are printed in the nozzle group in the A row.

[0056] Further t ₀ / the second time has elapsed, D operates the odd-numbered nozzles again B column nozzle group (2k-
1, j + 2) (k = 1, 2, ..., N), the odd-numbered dot groups are recorded. Even in the nozzle group of row A, odd-numbered dot groups represented by D (2k-1, j-N + 2) (k = 1, 2, ..., N) are recorded.

In this way, dot formation by the A-row nozzle group and the B-row nozzle group is performed for each of the odd-numbered dot group and the even-numbered dot group. Considering each dot row, B
After the even-numbered or odd-numbered dots are formed by the row nozzle group, after a time T = t ₀ × N, the remaining odd-numbered or even-numbered dots are formed by the row-A nozzle group to form a complete dot row. The formation of this dot row is shown in FIG.
This is the same as the manner of forming the dot row shown in FIG.

FIG. 11 is a circuit block diagram of an example of a control circuit for realizing the above-described operation of the print head in the ink jet printer according to the present invention.

With reference to FIG. 11, this ink jet plink has an input port 40 for receiving print data from the outside.
And a bus 42 connected to the input port 40, and a bus 42
Connected to the CPU 44 for controlling the entire inkjet printer, a program executed by the CPU 44, a character dot pattern for character printing, and other necessary information stored in advance in the ROM 46.
And a RAM 4 connected to the bus 42 and used as a buffer area for temporarily storing print data input from the input port 40, a work area of the CPU 44, and the like.
8 and a print data output port 50 which is connected to the bus 42 and which outputs a dot pattern for each character row in response to a command from the CPU 44, and a CPU 42 which is connected to the bus 42.
A drive signal output port 52 for outputting a drive signal to a drive system of the ink jet printer in response to a command from 4.
It includes a timer / counter 54 connected to the bus 42 for outputting a timing signal serving as a reference for the operation of the inkjet printer.

A motor 56 and a motor driver 58 connected to the drive signal output port 52 for changing the relative position between the print head and the recording paper, and the relative positional relationship between the print head and the recording paper are detected. A head position detecting means 60 for outputting a head position detecting signal, a print pulse generating means 62 connected to the timer / counter 54 for outputting a print pulse indicating a print timing, a print data output port 50, Print pulse generation means 62,
An electrode signal generation circuit 64 that is connected to the drive signal output port 52, receives a dot pattern for one column to express a character, and outputs an electrode signal applied to the side wall electrode of each ink chamber, and an electrode signal generation circuit. A print head 66 connected to the circuit 64 for ejecting ink onto the recording paper to form a character as an array of dots.

The print head 66 includes a first electrode group 68 and a second electrode group 7 each connected to the electrode signal generating circuit 64.
0 is included. The first electrode group 68 is for driving the nozzle group of row B shown in FIG. Second electrode group 7
0 is for driving the nozzles in the row A shown in FIG.

The print pulse generating means 62 is connected to the electrode signal generating circuit 64 by the signal line 63. The print data output port 50 and the electrode signal generation circuit 64 are 2n
They are connected by a signal line 51 of a book. The drive signal output port 52 is connected to the electrode signal generation circuit 64 by a signal line 53. The first electrode group 68 and the second electrode group 70 are connected to the electrode signal generation circuit 64 by 2n connection lines 69 and 71, respectively.

FIG. 12 is a more detailed circuit block diagram of the electrode signal generating circuit 64. With reference to FIG. 12, the electrode signal generation circuit 64 receives a dot pattern signal representing a dot pattern of 1 column of a character to be printed from 2n signal lines 51, and an ODD input from a signal line 53.
A first ODD for outputting an odd-numbered dot signal for driving an odd-numbered electrode of the first electrode group 68 and an even-numbered dot signal for driving an even-numbered electrode in response to the / EVEN switching signal. / EVEN switching circuit 72 and the first O
A first electrode signal gate circuit 74 connected to the DD / EVEN switching circuit 72, which outputs an electrode signal for driving the first electrode group 68 in response to a print pulse input from the connection line 63, and the signal line 51. In order to input and store a dot pattern signal representing a dot pattern for one line of a character to be printed from, to shift by one stage in response to an input pulse signal from the signal line 63, and to output after shifting N stages. 2n × N-stage shift register 76 and ODD / EV from the connection line 53 connected to the 2n × N-stage shift register 76
In response to the EN switching signal, an odd-numbered dot signal for driving an odd-numbered electrode of the second electrode group 70 and an even-numbered dot signal for driving an even-numbered electrode of the second electrode group 70 are provided. Second ODD / E for switching and alternately outputting
A second VEN switching circuit 78 and a second ODD / EVEN switching circuit 78, which output an electrode signal for driving the second electrode group 70 in response to a print pulse input from the control line 63. An electrode signal gate circuit 80 is included.

FIG. 13 is a more detailed block diagram of the first ODD / EVEN switching circuit 72. With reference to FIG. 13, the first ODD / EVEN switching circuit 72 has a signal b1 indicating ON / OFF of one dot of a dot pattern for one column of a character to be printed, on one of the respective inputs.
Is input, and the constant potential “1” is input to the other, and ODD
It includes 2n select 82 for switching between b1 and "l" for output in response to the / EVEN switching signal. It should be noted that the signal b1 and the constant potential “l” are different between the input to the even-numbered selector 82 and the input to the odd-numbered selector 82.
The connection with is reversed.

FIG. 14 is a more detailed block diagram of the 2n × N stage shift register 76 and the second ODD / EVEN switching circuit 78. Referring to FIG. 14, 2n × N-stage shift register 76 receives and stores signal b1 representing ON / OFF for 1 dot of the dot pattern for 1 column of the character to be printed, and stores it in signal line 63. It includes 2n N-stage shift registers 84 which shift one stage at a time in response to a print pulse input from, and output after shifting by N stages.

The structure of the second ODD / EVEN switching circuit 78 is exactly the same as the structure of the first ODD / EVEN switching circuit 72, and includes 2n selectors 86. However, the dot pattern signal delayed by the time corresponding to N times printing by the N-stage shift register 84 is input to the selector 86.

The operation of the ink jet printer will be described with reference to FIGS. A character code indicating a character to be printed is input to the input port 40 from the outside. The timer / counter 54 detects the end of the recording operation of the previous character by the head position detection signal and sends an interrupt signal to the CPU 44.

The CPU 44 responds to the interrupt signal by storing the character code input from the input port 40 in the RAM 48.
Once. The CPU 44 reads the first character code to be printed from the RAM 48, and reads the dot pattern of that character from the dot patterns stored in the ROM 46.

The CPU 44 further outputs a dot signal representing the dot pattern for one column of the dot pattern to the print data output port 50. At the same time, the CPU 44 outputs to the drive signal output port 52 an ODD / EVEN switching signal that specifies switching between forming odd-numbered dots and even-numbered dots. When the piezoelectric body forming the side wall of the ink chamber is polarized in the direction shown in FIG. 3B, it is driven among the two side wall electrodes provided on both sides of the side wall. The potential of the side wall electrode on the ink chamber side is set lower than the potential of the side wall electrode on the ink chamber side that is not driven.

On the other hand, the dot signal representing the dot of the character means that the dot is recorded when the value is "l" and the dot is not recorded when the value is "0". Therefore, the dot signals input to the first ODD / EVEN switching circuit 72 and the 2n × N-stage shift register 76 have been inverted in advance. In FIG. 13, the bar drawn above the dot signal b1 means the inversion of the above signal.

The inverted dot signal b1 is directly input to the first ODD / EVEN switching circuit 72.
On the other hand, the dot signal b1 input to the 2n × N-stage shift register 76 is delayed by the time corresponding to the printing operation for N times and input to the second ODD / EVEN switching circuit 78.
Each of the selectors 82 and 86 selects and outputs either the dot signal b1 or "1" in response to the ODD / EVEN switching signal. However, this selection is performed as follows.

When the ODD / EVEN switching signal is at the high level, the odd-numbered selectors 82 and 86 output the dot signal b1 and the even-numbered selectors 82 and 86 output the constant voltage "l". On the other hand, when the ODD / EVEN switching signal is at the low level, the odd-numbered selectors 82 and 86 output the constant potential “l”, and the even-numbered selectors 82 and 86.
Outputs the dot signal b1.

The print pulse generating means 62 uses the first ODD.
/ EVEN switching circuit 72 and second ODD / EVEN
The printing pulse signal is sent out when the output of the switching circuit 78 becomes stable. The first electrode signal gate circuit 74 and the second electrode signal gate circuit 80 amplify the voltage of the dot signal in response to the print pulse signal, and each of the first electrode group 68 and the second electrode group 70, respectively. The electrode signal given to the electrode is output.

At this time, if the ODD / EVEN switching signal is at high level, a high potential is uniformly applied to the even-numbered electrodes, and a ground potential or a high potential is applied to the odd-numbered electrodes depending on whether or not dots are formed. Given. Therefore, of the odd-numbered ink chambers, only the one to which the ground potential is applied,
The side wall is deformed inward and ejects ink. As a result, only odd-numbered dots are formed. At this time, the stored contents of each N-stage shift register 84 are shifted by one stage.

The motor 56 is driven by the CPU 44 via the motor driver 58 and the drive signal output port 52, and changes the relative position between the recording paper and the print head 66.

The head position detecting means 60 detects a change in the relative position between the recording paper and the print head 66 and outputs a head position detection signal. The CPU 44 detects the end of dot formation for one row by the head position detection signal via the timer / counter 54. However, actually, the two electrode groups 68 and 70 form odd-numbered dots in two columns separated by l = NXd.

The CPU 44 uses the print data output port 50.
Then, at the same time as outputting the dot pattern signal for the next one column, the ODD / EVEN switching signal is switched from the high level to the low level. As a result, the first ODD / EVEN
From the switching circuit 72, a dot signal for forming an even-numbered dot by each of the nozzles in the B row is supplied to the second ODD /
The EVEN switching circuit 78 outputs dot signals delayed N times for forming even-numbered dots by the nozzles in the A column. The printing pulse is generated similarly to the formation of the odd-numbered dots to record the even-numbered dots.

The CPU 44 repeats the above-described operation a predetermined number of times, and when printing of one character is completed, the next character is read from the RAM 48 and the same operation is repeated.
After printing all the characters in RAM 48, CP
The operation of U44 returns again to store the character code arriving at the input port 40 in the RAM 48. By the above-described operation, the dot array is formed on the recording paper in the form as shown in FIGS. 7 (A) to 7 (C).

FIGS. 15A and 15B are diagrams showing the print pulse generation timing and the change in the ODD / EVEN switching signal, respectively. As shown in FIGS. 15A and 15B, the ODD / EVEN switching signal alternately takes a high level value and a low level value each time one dot row is formed. As a result, even-numbered dots and odd-numbered dots are formed alternately.

In the above embodiment, the ink jet print head utilizing the shear deformation using the inverse piezoelectric effect was used. However, the present invention is not limited to the above-described embodiment, and can be applied to any one as long as it uses the ink ejection method that utilizes the deformation of the side wall separating the ink chambers.

In the above embodiment, the case where N is an odd number has been described. However, the present invention is not limited to this. When N is an even number, for example, among the nozzle groups arranged in two rows, when one row forms an even dot, the other row may form an odd dot. In this case, it is sufficient to slightly change the manual connection of each selector 86 in the second ODD / EVEN switching circuit 78.

Further, in the above embodiment, the generation of the electrode signal is realized by the circuit. However, the invention is not so limited. For example C
The value of each electrode signal may be determined by a program executed in the PU 44.

[0083]

In the ink jet plink according to the present invention, the first ejection control means characterizes the ink ejection nozzles selected every other lth ink ejection nozzle array in the preceding cycle of repetition. The ejection control is performed according to the data of the dot array that should express

The second ejection control means is selected every other second ink ejection nozzle in the subsequent cycle of repetition, and is selected in the preceding cycle of the arrangement of the first ink ejection nozzles. The ink ejection nozzles at positions different from the ink ejection nozzles are ejection-controlled in accordance with the dot array data that should represent the character.

A recharacter is represented by a combination of the dot arrays of the ejected ink of the nozzles of the first ink ejecting nozzle array and the nozzles of the second ink ejecting nozzle array. Therefore, the printing of one line of junk is completed by one printing operation.

During that time, it is not necessary to stop the movement of the print head. Therefore. High-speed printing operation can be easily realized.

Further, the arrangement of the ink jet nozzles arranged in two rows is compact, and it is not necessary to enlarge the head in order to realize high speed printing. Further, since it is not necessary to print many lines at once, a large area buffer is not needed. Therefore, a significant increase in cost can be avoided.

Therefore, it is possible to provide the ink jet printer which can speed up the printing without increasing the cost.

[Brief description of the drawings]

FIG. 1 is a partially exploded perspective view of a print head of an inkjet printer according to an embodiment of the present invention.

FIG. 2 is an exploded perspective view of the print head shown in FIG.

3A is a sectional view taken along the line IIIA-IIIA in FIG. 1, and FIG. 3B is a sectional view taken along the line IIIB-IIIB in FIG.

FIG. 4 is a schematic plan view of a dot array formed on a recording sheet.

5 is a view showing an operation state of the print head shown in FIG.
It is a IB-IIIB direction arrow sectional view.

6A and 6B are plan views of the orifice plate of the inkjet printer according to the present invention.

7A to 7C are schematic plan views showing formation of dot arrays by the inkjet printer according to the present invention.

FIG. 8 is a plan view of a nozzle orifice of an inkjet printer according to another embodiment of the present invention.

FIG. 9 is a schematic plan view showing a process of forming a dot array according to the present invention.

FIGS. 10A and 10B are timing charts showing the timing of dot formation by one nozzle of each of the two columns of the inkjet printer according to the present invention.

FIG. 11 is a circuit block diagram of an embodiment of the present invention.

FIG. 12 is a more detailed block diagram of the electrode signal generation circuit according to the embodiment of the present invention.

FIG. 13 is a first ODD / E according to the embodiment of the present invention.
It is a block diagram of a VEN switching circuit.

FIG. 14 is a block diagram of a 2n × N-stage shift register and a second ODD / EVEN switching circuit according to the embodiment of the present invention.

FIG. 15 is a print pulse according to the embodiment of the present invention;
9 is a timing chart showing a relationship with an ODD / EVEN switching completion message.

FIG. 16 is a partially exploded perspective view of a print head of a conventional inkjet printer.

17A and 17B are cross-sectional views of a side wall of an ink chamber formed of a piezoelectric material.

FIG. 18 is a cross-sectional view taken along arrow XVI-XVI in FIG. 16 showing the operating condition of the print head of the conventional inkjet printer.

[Explanation of symbols]

 10 First Multi-Nozzle Head 12 Second Multi-Nozzle Head 14 Orifice Plate 16 First Ink Chamber Base 18 First Ink Chamber Cover Block 20 Sidewall Electrode 22 Driving IC 28 Second Ink Chamber Base 30 Second Ink chamber cover block 32 Side wall electrode 33 Ink chamber 34 Ink chamber 38 Nozzle orifice 40 Human power port 42 Bus 44 CPU 46 ROM 48 RAM 50 Print data output port 52 Drive signal output port 54 Timer / counter 60 Head position detection means 62 Print pulse generation Means 64 Electrode signal generation circuit 66 Print head 68 First electrode group 70 Second electrode group 72 First ODD / EVEN switching circuit 74 First electrode signal gate circuit 76 2n × N-stage shift register 78 Second ODD / EVEN switching circuit 8 0 second electrode signal gate circuit 82 selector 84 N-stage shift register 86 selector

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[Procedure amendment]

[Submission date] August 2, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 1

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0019

[Correction method] Change

[Correction contents]

[0019]

An ink jet printer according to the present invention includes an array of a plurality of aligned and individually controllable ink jet nozzles, and is arranged in a direction intersecting with an object to be recorded. An ink jet printer in which a character is expressed as a dot array of ejected ink in an alignment direction and a cross direction by individually controlling ejection of ink while performing relative displacement between the ink ejection nozzles. Has an ink chamber
Ink chamber cover covering the base and the surface of the ink chamber base
Forming a first nozzle head and a second nozzle head from the member,
The above-described ink jetting is performed on one side surface of the first and second nozzle heads.
While forming the opening of the injection nozzle, the ink on the other side
Driving the ink jet nozzle on the surface of the chamber base
A drive unit is provided for the ink chamber base of the first nozzle head.
Of the ink chamber base of the second nozzle head
The back surface is fixed, and the first and second nozzle heads
To cover the opening of the ink ejection nozzle on one side,
First nozzle orifice corresponding to each ink jet nozzle
And an array of second nozzle orifices.
An orifice plate is provided.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0020

[Correction method] Change

[Correction contents]

The above ink jet printer has the first
The ink ejection nozzle of the nozzle head and the second nozzle
The ink jet nozzle of the head is driven by the drive unit,
Ejection by the ink ejection nozzle of the first nozzle head
Dot array and ink ejection nozzle of the second nozzle head
Key in combination with the dot array of ejected ink
Express the character.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0021

[Correction method] Deleted

[Procedure Amendment 5]

[Document name to be amended] Statement

[Correction target item name] 0022

[Correction method] Deleted

[Procedure correction 6]

[Document name to be amended] Statement

[Correction target item name] 0023

[Correction method] Deleted

[Procedure amendment 7]

[Document name to be amended] Statement

[Correction target item name] 0040

[Correction method] Change

[Correction contents]

With reference to FIG. 5, each of the ink chamber group in the A row and the ink chamber group in the B row is driven similarly to the ink chamber group in the conventional technique. That is, the side walls 13 and 15 to which a predetermined potential difference is applied between the side wall electrodes on both sides cause shear deformation in the direction corresponding to the polarization direction. Ink chamber 3
Of the parts 3, 34, the ones whose both side walls are deformed inward have a reduced volume. Ink chamber 3 with reduced volume
The insides of the ink cartridges 3 and 34 are filled with the ink previously supplied from the ink introducing hole 36. Therefore the reduced pressure inside the ink chambers 33, 34 thereof volume increases, ink is ejected from the nozzle orifice 3 8.

[Procedure amendment 8]

[Document name to be amended] Statement

[Correction target item name] 0083

[Correction method] Change

[Correction contents]

The ink jet printer according to the present invention has a plurality of ink ejecting nozzles,
And an ink chamber cover portion that covers the surface of the ink chamber base.
Forming a first nozzle head and a second nozzle head from the material,
Ink jetting on one side surface of the first and second nozzle heads
In addition to forming the nozzle opening, the ink chamber on the other side
Drive the above ink jet nozzles on the surface of the base.
An ink chamber base for the first nozzle head
And the back of the ink chamber base of the second nozzle head
The surface of the first and second nozzle heads.
Each of the above so as to cover the opening of the side ink jet nozzle.
First nozzle orifice corresponding to the ink jet nozzle of
And an array of second nozzle orifices.
Ink of the first nozzle head with a refill plate
Ink ejection nozzles of the ejection nozzle and the second nozzle head
Of the first nozzle head by driving the
Second dot array of ink jetted by the ink jet nozzle and second
Of the ink jet from the ink jet nozzle of the nozzle head of
Characters are expressed by combining with a dot array.
You.

[Procedure amendment 9]

[Document name to be amended] Statement

[Correction target item name]

[Correction method] Deleted

[Procedure amendment 10]

[Document name to be amended] Statement

[Correction target item name] 0085

[Correction method] Change

[Correction contents]

In the ink jet nozzle of the first nozzle head
Of the ejected ink and the second nozzle head
Because represented character by a combination of a dot array of ejection ink by the ink jet nozzles, printing of calibration <br/> Rakuta of one row is completed by a single printing operation.

[Procedure amendment 11]

[Document name to be amended] Statement

[Correction target item name] 0088

[Correction method] Change

[Correction contents]

Therefore, it is possible to provide the ink jet printer which can speed up the printing without increasing the cost. Moreover, to the first and second nozzles
To cover the opening of the ink jet nozzle on one side of the lid,
A first nozzle nozzle corresponding to each of the above ink jet nozzles.
The arrangement of the Liffith and the arrangement of the second nozzle orifice
Since it has an orifice plate,
Dimensional errors during manufacture of the slip head and the second nozzle head,
The first nozzle nozzle is not affected by misalignment during sticking.
Make sure that the alignment position of the Liffith and the second nozzle orifice is accurate.
Can be formed without any problems, and the ejection
It is possible to accurately obtain the dot array of the links, and
Characters can be accurately and clearly expressed. Ma
In addition, electrical connection such as control signal and power supply to the drive unit
It can be done easily.

[Procedure amendment 12]

[Document name to be amended] Drawing

[Correction target item name] Figure 2

[Correction method] Change

[Correction contents]

[Fig. 2]

Claims (1)

[Claims] 1. An ink jet nozzle including an array of a plurality of aligned and individually controllable ink jet nozzles, wherein the ink jet nozzle is relatively displaced with respect to a recording object in an alignment direction and a crossing direction. An inkjet printer in which a character is represented as a dot array of ejected ink in the alignment direction and the intersecting direction by individually ejecting the ink jet nozzles, and the array of ink jet nozzles is arranged side by side. An array of first ink ejection nozzles and an array of second ink ejection nozzles, wherein every other ink ejection nozzle of the first ink ejection nozzle array is selected in a preceding cycle of repetition. A first ejection control means for controlling ejection in accordance with dot array data representing the character, and the second ink in a subsequent cycle of repetition. An ink ejection nozzle that is selected for every other ejection nozzle and that is at a position different from the ink ejection nozzle that is selected for every other ejection arrangement of the first ink ejection nozzles has a dot arrangement for expressing the character. Second ejection control means for controlling ejection according to data, whereby a set of ejection ink dot arrangements of the nozzles of the first ink ejection nozzle array and the nozzles of the second ink ejection nozzle array Inkjet printer where characters are expressed by matching.