JP2002120365A - Head driver and method for driving head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a head driver for ink jet recorder, and the like, and a method for driving a head in which the data volume and the processing time of head drive waveform can be limited and highly accurate control can be ensured without increasing them. SOLUTION: Count data 11 of head drive operation is compared with a plurality of time data 12 except those having 0 head drive current value and if the count data 11 is equal to one of the plurality of time data 12, current data 14 indicated by the time data 12 is outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a head driving apparatus and a head driving method for an ink jet recording apparatus.

[0002]

2. Description of the Related Art In the field of an ink jet recording apparatus, two systems, a thermal system and a piezo system, have become widespread. Among them, the piezo system is composed of a piezoelectric element to form an actuator and eject ink droplets. It has a feature that the droplet amount and the landing position can be accurately controlled.

Hereinafter, the driving waveform of the piezo type ink jet head will be described with reference to the drawings.

FIG. 5A is a schematic diagram showing an example of a conventional head drive waveform as a voltage waveform, FIG. 5B is a schematic diagram showing an example of a conventional head drive waveform as a current waveform, and FIG. 3C is a schematic diagram showing a change in the meniscus and actuator of the conventional head, and the state of the ink droplet flying.

In FIG. 5, T on the time axis is a printing cycle for forming one pixel, and t1, t2, t3, t4, t
5, t6, t7, and t8 indicate the time of the change point of the drive waveform,
a, Vb, Vc, Vd are voltage values for displacing the actuator, Ia, Ib, Ic, Id are current values for displacing the actuator, 81 is a part of a head relating to ink ejection, 82 is an actuator, and 83 is an actuator. A meniscus 84 is an ejected ink droplet, (91) (92) (93) (9)
4) shows a state of displacement between the actuator and the meniscus.

Although the waveforms of the voltage waveform shown in FIG. 5A and the current waveform shown in FIG. 5B are greatly different from each other, the waveforms are completely equivalent in consideration of the fact that the actuator is a capacitive load. Here, the current waveform will be described as an example.

Time 0 is a steady state (91), and time t
When the actuator 82 is charged from 1 with the current Ib, the actuator 82 starts to be displaced in a direction to push out the meniscus 83, and is displaced at time t2 until a state (92). After maintaining this state until time t3, the current Ic is continued until time t4.
Causes the actuator 82 to pull back the meniscus 83 to the state (93),
When the actuator 82 is rapidly charged with the current Id larger than the current Ib until the time t6 after the holding until the time t5, the actuator 82 changes the meniscus 83 to the state (9).
4), the ink droplet 84 is ejected, and this state is maintained until t7.
The actuator 82 is discharged with a current Ia smaller than c, and the meniscus 83 is gradually pulled back to return to a flat steady state (9).
Return to 1).

The above operation is defined as one printing cycle, and an image is formed by repeating this operation a required number of times.

Next, a description will be given of a conventional head drive waveform generation circuit for realizing the above-described operation.

FIG. 3 shows an example of the drive current waveform of the head actuator. T1 to t8 indicate the time of the current change point, and the numerical value in parentheses below indicates the time data (Hex display; hereinafter, all data are Hex). Display), t9 to t11 are the times of the reference clock included in the period when the current is not 0, the numerical value in parentheses below is the time data representing the time, I
a, Ib, Ic, and Id denote current values, and numerical values in parentheses indicate current data. The direction in which the current flows into the head actuator is plus, the direction in which the current flows out of the head actuator is minus, and the data when the current value is 0 is 7F.

In FIG. 3, if the printing cycle is 128 μs
ec, the time resolution is 0.5 μsec, and the drive current waveform for one printing cycle is expressed as current data / time data, and is expressed as 7F / 00, 7F / 01, 7F / 02,.
27, A3 / 28, A3 / 29, 7F / 2A ..., 7F /
59, 19 / 5A, 7F / 5B, ..., 7F / 6D, F4
/ 6E, 7F / 6F ..., 7F / 8B, 42 / 8C, 42
/ 8D, 42 / 8E, 7F / 8F, ..., 7F / FF
It becomes 56 pieces.

Next, two examples of generating the above-described head drive current waveform will be described. FIG. 6 is an example of a block diagram in the case where a head drive device is configured using a conventional memory.

In FIG. 6, reference numeral 1 denotes a counter which receives a clear signal for clearing data at the beginning of a printing cycle and a clock signal as a time reference, and 121 denotes count data 1
A memory which outputs current data 14 of a head drive waveform using 1 as an address, and 7 is a memory output, that is, a current data 14
A digital-to-analog converter (DAC) which receives digital data of the input and converts it into analog data and outputs the data,
An amplifier circuit which receives an AC output 17 as an input and amplifies the input;
Is a head that receives the amplifier circuit output 18 as input and displaces the actuator to eject ink droplets, and heads 7, 8, and 9 constitute a head block.

A CPU (not shown) for controlling the system of the ink jet recording apparatus before starting the head driving operation
To store current data 14 in memory 1
Write to 21. The counter 1 repeats the clearing and counting operations in each printing cycle according to the printing operation of the ink jet recording apparatus, supplies the current time, that is, the count data 11 to the memory 121 as an address, and outputs the driving waveform current data 14 from the memory 121. You. The current data 14 is converted into an analog value by the DAC 7, amplified by the amplifier circuit 8, supplied to the head 9, and ejecting an ink droplet by displacing the actuator 82.

Next, another example using a shift register will be described with reference to the block diagram of FIG. FIG. 7 is a block diagram in the case where a head drive device is configured using a conventional shift register.

In FIG. 7, reference numeral 141 denotes a shift register which holds the current data 14 of the head drive waveform for one printing cycle. The number of the registers is equal to the number of data in one printing cycle. A clock signal which is wired so as to return to the input and serves as a time reference is input to the clock input. The circuits subsequent to the DAC 7 have the same configuration as in FIG. 7, and a description thereof will be omitted.

A CPU (not shown) for controlling the system of the ink jet recording apparatus before starting the head driving operation
Current data 14 for one printing cycle arranged in order of time
Is written to the shift register 141. Shift register 1
41 outputs the current data 14 of the drive waveform in synchronization with the clock in accordance with the printing operation of the ink jet recording apparatus.
Since the number of registers of the shift register 141 is equal to the number of data in one printing cycle and the output is returned to the input, the head drive waveform is repeatedly output in synchronization with the printing cycle.

The case where a 256B head drive waveform is generated has been described above with reference to two examples. Next, the process of creating the 256B head drive current data will be described with reference to FIGS. . FIG. 8 is a diagram showing a head drive current waveform when the head drive waveform is corrected by changing only the current value at the same timing in the related art, and FIG. 9 is a diagram showing an example of a temperature characteristic of the conventional head drive current. FIG. 10 is a processing flowchart in a conventional head driving device, and FIG. 11 is a diagram showing a conventional head driving current waveform in a case where the head driving waveform is corrected by changing both the timing and the current value. FIG. 12 is a schematic diagram showing the relationship between the temperatures of a conventional head driving device, FIG. 13 is an enlarged schematic diagram of a part of the head driving current waveform shown in FIG. 12, and FIG. FIG. 15 is a schematic diagram showing linear interpolation of values, and FIG. 15 is a processing flowchart in a conventional head driving device.

In the ink jet head, the discharge performance of the ink droplets, that is, the discharge amount and the discharge speed are greatly affected by the ambient temperature, particularly the ink temperature, so that the head drive waveform must be corrected according to the temperature. . The correction may be performed by changing only the current value while maintaining the same timing, or may be performed by changing both the timing and the current value.

First, a case where the correction is performed by changing only the current value at the same timing with reference to FIGS. 8 to 10 will be described. In FIG. 8, 161 and 162 are examples of head drive waveforms at different temperatures. The current value changes, but the timing is the same. FIG. 9 shows an example of a temperature characteristic of how to change the current value. In general, when the temperature of the ink is low, the viscosity increases, so that stronger driving energy is required. Therefore, the current value is high at low temperatures and low at high temperatures. Although this temperature characteristic is non-linear with respect to temperature, if a correction data table is provided for all head operating temperatures, the amount of data becomes enormous. Only the table is held, and the temperature at the time of the actual operation is calculated by a method such as linear interpolation based on the reference data tables on both sides adjacent to the temperature. FIG. 10 shows a processing flowchart at this time. In this case,
The total amount of data that must be retained is 256B x
10 = 2560B.

Next, a case where the correction is performed by changing both the timing and the current value will be described with reference to FIGS. In FIG. 11, reference numerals 221 and 222 denote examples of head drive waveforms at different temperatures. This indicates that both the current value and the timing have changed. 12, reference numeral 243 denotes a temperature during a certain operation, and reference numerals 241 and 242 denote reference temperatures on both sides of the temperature of 243. The temperature difference between 243 and 242 is TEMP1, and the temperature difference between 243 and 241 is TEMP2.

FIG. 13 is an enlarged view of a portion surrounded by an ellipse in FIG. 11, and a description will be given of a case where a waveform at a certain operating temperature is obtained from the reference temperature waveform for this portion. First, as for the rising timing of the waveform, the difference between the timing between the reference temperature 262 and the operating temperature 263 is T1, the difference between the reference temperature 261 and the operating temperature 263 is T2, and the falling timing of the waveform is T1. The difference between the timing between the reference temperature 262 and the operating temperature 263 is T3, the difference between the reference temperature 261 and the operating temperature 263 is T4, and the current value is the reference temperature 2
I1 is the difference between the current value of the reference temperature 261 and the operating temperature 263, and I1 is the difference of the current value between the reference temperature 261 and the operating temperature 263.
Let 2.

The relationship between the timing and the current data at this time is as follows: T1: T2 = T3: T4 = I1: I2 = TEMP1: T
It becomes EMP2, and the timing and current value at the time of operating temperature 263 can be obtained by linear interpolation. The head drive waveform is as shown at 263 in FIG. FIG. 14 shows that an area obtained by linear interpolation for the timing and an area obtained by linear interpolation for the current value are synthesized by AND logic. FIG. 15 shows a processing flowchart at this time.

As described above, in the conventional technique, the printing cycle is 128 μsec and the time resolution is 0.5 μsec.
Holds the drive current waveform data for one printing cycle,
In order to output the data, a memory of 256 bytes (hereinafter abbreviated as B) and a data holding means such as a shift register are required,
Further, a means for holding data of 256B × 10 = 2560B as 10-point reference data for temperature correction is required. Also, as for the processing time of these data, the data processing time of 256B × 3 = 768B is required in combination with the data at the two reference temperatures and the data at the current temperature.

Further, if the time resolution is doubled to 0.25 μsec for the purpose of higher precision control, the current data for one printing cycle is 512B, the reference data for temperature correction is 5120B, and the data processing is performed. Time is 15
36B, which is a result of doubling in proportion to the resolution.

[0026]

In the above-described conventional head driving apparatus, a large amount of data must be held and processed for generating a head driving waveform, and in addition, higher quality printing is achieved. Therefore, when the resolution of the head drive waveform data is increased, both the data amount and the processing time increase in proportion to the resolution, causing a problem that hardware resources increase and printing speed decreases.

The present invention relates to a head driving device and a head driving device, such as an ink jet recording device, which can reduce the data amount and processing time of a head driving waveform, and can perform higher precision control without increasing these. It is an object to provide a driving method.

[0028]

According to the present invention, there is provided a counter for counting a reference clock, a plurality of current data holding means for holding head drive current data except for a current value of 0, and a time data paired with the current data. A plurality of time data holding means, a plurality of comparators outputting a coincidence signal between the count data of the counter and the time data of the time data holding means, and the time data when the coincidence signal of the comparator is true. Output switching means for outputting current data of the current data holding means paired with the holding means and outputting current data of a current value 0 when the coincidence signal of the comparator is false.

[0029]

According to the first aspect of the present invention, a counter for counting a reference clock, a plurality of current data holding means for holding head drive current data except for a current value of 0, and a pair of current data are provided. A plurality of time data holding means for holding time data; a plurality of comparators for outputting a coincidence signal between the count data of the counter and the time data of the time data holding means; and a time data holding means when the coincidence signal of the comparator is true. Output switching means for outputting the current data of the current data holding means paired with the current data holding means and outputting the current data of the current value 0 when the coincidence signal of the comparator is false. It is no longer necessary to hold all the current data, and the head drive waveform is generated only by holding the current data other than the current value 0 and the time data. Data of the head driving waveform because it is possible, it is possible to reduce the processing time,
Since the data amount does not increase even if the resolution of the head drive waveform is increased, an increase in hardware resources and a decrease in printing speed can be prevented.

According to a second aspect of the present invention, the current time of the head driving operation is compared with a plurality of time data having a head driving current value other than 0, and the current time becomes equal to one of the plurality of time data. In this case, by outputting the current data at the time indicated by the time data, it is not necessary to hold all the current data in one print cycle of the head drive waveform.
Since the head drive waveform can be generated only by holding the current data other than the current value 0 and the time data, the data amount and the processing time of the head drive waveform can be suppressed and the resolution of the head drive waveform can be reduced. Since increasing the data amount does not increase the data amount, it is possible to prevent an increase in hardware resources and a decrease in printing speed.

According to a third aspect of the present invention, the current time of the head drive operation is compared with a plurality of time data having a head drive current value other than 0, and the current time becomes equal to one of the plurality of time data. In this case, the current data at the time indicated by the time data is output, and when the current time is not equal to any of the plurality of time data, the current data of the current value 0 is output, thereby printing one head drive waveform. It is not necessary to hold all the current data of the cycle, and the head drive waveform can be generated only by holding the current data other than the current value 0 and the time data. Therefore, the data amount and the processing time of the head drive waveform can be reduced. It can be kept low and the data amount does not increase even if the resolution of the head drive waveform is increased, thus preventing an increase in hardware resources and a decrease in printing speed. It is possible.

According to the present invention, the current time of the head drive operation is compared with a plurality of time data in which the head drive current value is other than 0, and the current time becomes equal to the first time data. In this case, the current data at the time indicated by the first time data is output, and thereafter, if the current time is not equal to any of the plurality of time data, the current data of the current value 0 is output, and the current time and the The second time data is compared with the second time data, and when the current time becomes equal to the second time data, the current data at the time indicated by the second time data is output, so that the entirety of one print cycle of the head drive waveform is output. Therefore, the head drive waveform can be generated only by holding the current data other than the current value 0 and the time data, so that the data amount of the head drive waveform and the processing time It is possible to suppress, since there can also increase the amount of data by increasing the resolution of the head driving waveform, it is possible to prevent a decrease in printing speed and increase in the hardware resources.

According to the fifth aspect of the present invention, since the holding means is a register, an access method to the holding means can be made easier as compared with the case where other memory means is used, and the apparatus has a structure. Hardware can be simplified.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
4 will be described.

FIG. 1 is a block diagram of a head driving device according to an embodiment of the present invention, and particularly illustrates a waveform generating circuit in detail. FIG. 2 is a timing chart showing an outline of the operation of the head driving device according to the embodiment of the present invention;
FIG. 3 is a schematic diagram illustrating an example of a head drive current waveform according to the embodiment of the present invention, and FIG. 4 is a block diagram illustrating a schematic configuration of an ink jet recording apparatus equipped with the head drive device according to the embodiment of the present invention.

In FIG. 4, reference numeral 41 denotes a CPU for controlling the entire system of the ink jet printing apparatus; 42, a memory for storing system programs and data; 43, an interface for controlling communication between the ink jet printing apparatus and devices such as a personal computer. , A head control unit 44 for generating a head drive waveform and a head print data; and 45, a paper transport motor 46 and a carriage motor 47.
Is a motor control unit that controls the rotation of the motor.

Hereinafter, the generation of the head drive waveform in the head control unit 44 in FIG. 4 will be described in detail.

First, the case where the head drive waveform of FIG. 3 is generated by the circuit of the block diagram of FIG. 1 will be described.

The counter 1 shown in FIG. 1 counts the clock signal, and the count data 11 is cleared by the clear signal. The time data register 2 is a register in which the time data 12 when the head drive current value is other than 0 is written by the control means such as the CPU 41 and holds the time data 12, and always outputs the held time data 12 to the comparator 3. Continue to do. The time data 12 is supplied from the comparator 3 to the count data 11 of the counter 1, that is,
It is always compared with the elapsed time (current time) from the clear, and when the count data 11 and the time data 12 do not match, the match signal 13 output from the comparator 3
Becomes false, and count data 11 and time data 1
When the two match, the match signal 13 output from the comparator 3 becomes true.

The current data register 4 for holding the current data 14 when the head drive current value is other than 0 is paired with the time data register 2 and the comparator 3, and the terminal for controlling its output is connected to the comparator 3 Match signal 1 of
3 is input. The current data register 4 normally does not output the held current data 14 (when the coincidence signal 13 from the comparator 3 is false),
When the coincidence signal 13 from the pair becomes true, current data 14 is output from the paired current data register 4.

The NOR logic circuit 5 receives a plurality of coincidence signals 13 from the comparator 3 and outputs a NOR logic output 15 to the current 0 data register 6. That is, the NOR logic output 15 outputs true when all the coincidence signals 13 are false. The current 0 data register 6 stores the current 0 data 14h at the time of the current 0 when the NOR logic output 15 becomes true.
Is output. The delay circuit 10 is provided with a DAC at a later stage.
7, a delay circuit for adjusting the timing with the amplifier circuit 8 and the head 9 (the description is omitted because it is described above).

In FIGS. 1 and 2, first, a CP for controlling the system of the ink jet recording apparatus as one of the printing operations, that is, one of the initialization operations before starting the head driving operation.
All time data when the head drive current value is other than 0 is stored by U41. For example, the value 28 corresponding to the time t1 is used as the time data 12a and the time data register 2a
To be stored. If this is abbreviated as t1 = 28 = 12a⇒2a, similarly, t9 = 29 = 12b⇒2b, t3 = 5A = 12c⇒2c, t5 = 6E = 12d⇒2d, t7 = 8C = 12e⇒2e, t10 = 8D = 12f → 2f, t11 = 8E = 12g → 2g, Similarly, the CPU 41 causes the head 41 to store all current data other than 0. For example, at time t1
Is stored in the current data register 4a as the current data 14a. If this is abbreviated as t1: A3 = 14a⇒4a, similarly, t9: A3 = 14b⇒4b, t3: 19 = 14c⇒4c, t5: F4 = 14d⇒4d, t7: 42 = 14e⇒4e, t10: 42 = 14f⇒4f, t11: 42 = 14g⇒4g, and the CPU 41 writes current 0 data 14h (7F in this case), which becomes current 0, into the current 0 data register 6, and terminates the initialization operation.

Next, the start of the printing cycle, that is, the time t =
When the counter 1 is cleared to 0, the count data 11 is cleared. When clearing is canceled and a clock serving as a reference for the timing of the head drive waveform is input, a count operation is started. At this time, all the match signals 13
Is false and the NOR logic output 15 becomes true, so that the current 0 data register 6 outputs the current 0 data 14h, that is, 7
F is output.

At time t1, the count data 11 becomes 2
8, the time data 12a of the time data register 2a,
That is, it is equal to 28. Then, the match signal 13a becomes true from the comparator 3a, whereby the current data 14a stored in the current data register 4a, that is, A
3 is output, and the NOR logic output 15 becomes false, so that the current 0 data register stops outputting. Therefore, the current data 14 becomes A3 and is input to the DAC 7. DA
The steps subsequent to C7 are the same as in the prior art, and a description thereof will be omitted.

The next clock after time t1 is input and time t
9, the match signal 13 is true, the NOR logic output 15 is false, and the current data
a is output, but this state is the same as at time t1.

At the time t2 when the next clock is input from the time t9, the count data 11 becomes 2A and is not equal to any of the time data.
Are all false and the NOR logic output 15 becomes true, so that the current 0 data 14h is output from the current 0 data register 6.

The above operation is repeated to generate a head drive waveform for one printing cycle.

As described above, the configuration in which the waveform is generated by the data of the current value when the head drive current value is other than 0 has a printing cycle of 128 μm as compared with the prior art.
sec, when the time resolution is 0.5 μsec, 1
In the present embodiment, the data amount for holding and outputting the drive current waveform data for the printing cycle required 256 B, but in the present embodiment, the time data 7 B and the current data 8
B is 15B, and the amount of reference data of 10 points for temperature correction is 1560, which is required by the conventional technology, which is 2560B.
50B, which is about 1/17, and a significant reduction in memory can be realized with a decrease in the data amount.

Naturally, the time required to process these data is reduced to about 1/17 in proportion to the data amount. Higher speed can also be achieved.

Further, the data for temperature correction is temporarily set to 0.
Even if all data are held at a resolution of 1 ° C. within the range of ５０50 ° C., the data can be stored at 750 B. Therefore, all data can be held as they are without calculating data from the reference data by a method such as linear interpolation. In this case, the time for processing the data becomes unnecessary, and only the data is transferred.

In the above embodiment, the regions (t1 to t2, t3 to t4, t5 to t) where the head drive current flows are set.
6, four times t7 to t8), two clocks of the reference clock are used between t1 and t2, and three clocks of the reference clock are used between t7 and t8. That is, with the speeding up and higher precision (higher resolution) of the head drive, the rise and fall of the head drive waveform are often increased steeply. When the area is one clock of the reference clock, the time data 4B and the current data 5B are combined into 9B data, which is about 1/28 compared with 256B of the prior art, and the effect is further enhanced.

In the above embodiment, the description has been given assuming that the current data 14 of the current 0 is normally output.
In the case where a small charge current is supplied to cancel the fluctuation of the bias potential of the head actuator due to the spontaneous discharge, it is possible to cope with it only by setting necessary charge current data in the current 0 data register 6.

Also, one time data register 2a has 1
The control logic can be simplified by storing the two time data 12a and providing the comparator 3a corresponding thereto and the current data register 4a storing the current data 14a corresponding to the time data 12a.

Further, the waveform between the times corresponding to the change points (for example, between time t1 and time t2 in FIG. 3) becomes linear, so that the amplifier circuit at the subsequent stage has special characteristics. Since there is no need to use an amplifier circuit having good linearity, the configuration of the amplifier circuit can be simplified.

In the above embodiment, the number of points of the head drive current other than 0 is seven. However, the present invention is not limited to the number of change points. It is needless to say that not only the register but also the comparator which compares the true / false of the match and the comparator which compares the magnitudes can perform the same function.

Further, the current data register 4, NOR
It is needless to say that the output switching means constituted by the logic circuit 5 and the current 0 data register 6 can be replaced as long as it has a function of holding and outputting current data when the conditions are satisfied by comparison with a comparator. .

[0057]

As described above, according to the present invention, the data amount and the processing time of the head drive waveform can be reduced, and the data amount and the processing time can be reduced even when the speed and resolution of the head drive waveform are increased. Increase can be suppressed.

[Brief description of the drawings]

FIG. 1 is a block diagram of a head driving device according to an embodiment of the present invention.

FIG. 2 is a timing chart showing an outline of an operation of the head driving device according to the embodiment of the present invention;

FIG. 3 is a schematic diagram showing an example of a head drive current waveform according to the embodiment of the present invention.

FIG. 4 is a block diagram illustrating a schematic configuration of an ink jet recording apparatus equipped with a head driving device according to an embodiment of the present invention.

5A is a schematic diagram illustrating an example of a conventional head drive waveform as a voltage waveform, FIG. 5B is a schematic diagram illustrating an example of a conventional head drive waveform as a current waveform, and FIG. 5C is a schematic diagram illustrating a conventional head actuator and a meniscus. Schematic diagram showing changes in ink droplets and flying states of ink droplets

FIG. 6 is a block diagram in the case where a head drive device is configured using a conventional memory.

FIG. 7 is a block diagram in the case where a head drive device is configured using a conventional shift register.

FIG. 8 is a diagram showing a head drive current waveform when the head drive waveform is corrected by changing only the current value at the same timing in the related art.

FIG. 9 is a diagram showing an example of a temperature characteristic of a conventional head drive current.

FIG. 10 is a processing flowchart in a conventional head driving device.

FIG. 11 is a diagram showing a conventional head drive current waveform when the head drive waveform is corrected by changing both the timing and the current value.

FIG. 12 is a schematic diagram showing a temperature relationship of a conventional head driving device.

FIG. 13 is an enlarged schematic view of a part of the head drive current waveform shown in FIG. 12;

FIG. 14 is a schematic diagram showing conventional linear interpolation of timing and current value.

FIG. 15 is a processing flowchart in a conventional head driving device.

[Explanation of symbols]

Reference Signs List 1 counter 2 time data register 3 comparator 4 current data register 5 NOR logic circuit 6 current 0 data register 7 digital-analog converter (DAC) 8 amplifier circuit 9 head 10 delay circuit 11 count data 12 time data 13 coincidence signal 14 current data 15 NOR logic output 17 DAC output 18 Amplifier output 41 CPU 42 Memory 43 Interface unit 44 Head control unit 45 Motor control unit 46 Paper transport motor 47 Carriage motor 81 Head (part related to ejection) 82 Actuator 83 Meniscus 84 Ink droplet 91 Head steady state 92 Head driving first state 93 Head driving second state 94 Head driving third state 121 Memory 141 Shift register 161 Head at a certain temperature Drive current waveform 162 Head drive current waveform at a temperature different from 161 221 Head drive current waveform at a certain temperature 222 Head drive current waveform at a certain temperature different from 221 241 A certain temperature 242 A certain temperature different from 241 243 Between 241 and 242 261 Head drive current waveform at a certain temperature 262 Head drive current waveform at a certain temperature different from 261 263 Head drive current waveform at a temperature between 263 261 and 262

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takanobu Kajikawa 1006 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Inventor Kenichi Kimori 1006 Kadoma Kadoma Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. (72) Inventor Michiki Nanro 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Industrial Co., Ltd. (reference) 2C057 AF05 AF64 AK02 AK07 AK15 AL26 AL31 AM17 AM22 AR08 AR16 BA03 BA14

Claims (5)

[Claims] A counter for counting a reference clock;
A plurality of current data holding means for holding head drive current data except for a current value of 0; a plurality of time data holding means for holding time data that is paired with the current data; a count data of the counter and a hold of the time data A plurality of comparators that output a coincidence signal with time data of the means, and when the coincidence signal of the comparator is true, output current data of the current data holding means paired with the time data holding means; An output switching means for outputting current data having a current value of 0 when the coincidence signal is false. 2. The method according to claim 1, wherein the current time of the head drive operation is compared with a plurality of time data having a head drive current value other than 0, and when the current time becomes equal to one of the plurality of time data, A head driving device for outputting current data at a time indicated by time data. 3. The method according to claim 1, wherein a current time of the head driving operation is compared with a plurality of time data having a head driving current value other than 0, and when the current time becomes equal to one of the plurality of time data, A head driving device that outputs current data at a time indicated by time data, and outputs current data having a current value of 0 when the current time is not equal to any of the plurality of time data. 4. A method for comparing a current time of a head driving operation with a plurality of time data having a head driving current value other than 0, and when the current time becomes equal to the first time data, The current data of the time indicated by the time data of 1 is output. If the current time is not equal to any of the plurality of time data, the current data of the current value 0 is output.
Thereafter, the current time is compared with the second time data, and when the current time becomes equal to the second time data, the current data at the time indicated by the second time data is output. Head driving method. 5. The head driving device according to claim 1, wherein the holding means is a register.