JP3512046B2 - Recording head drive voltage adjustment device for inkjet recording device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a recording head drive voltage adjusting device for an ink jet recording apparatus, and more particularly, it is based on the temperature of the recording head as a reference voltage input to a drive voltage adjusting circuit for adjusting the drive voltage of the recording head. The present invention relates to a device in which a smoothed voltage obtained by smoothing a generated reference voltage adjusting pulse signal is applied.

[0002]

2. Description of the Related Art Conventionally, in an ink jet recording apparatus, recording ink contained in an ink cartridge is supplied to a plurality of fine ink supply passages provided in a recording head through a so-called manifold, while supplying each ink. By driving the piezoelectric element provided in the passage in accordance with the image data, the ink is ejected from the ejection nozzle provided at the tip of the recording head for recording, and therefore the outside air temperature, that is, the temperature of the recording head. , The viscosity of the ink becomes high, and the ink ejection performance deteriorates. Therefore, by increasing the drive voltage supplied to the piezoelectric element, the ink ejection force is increased, especially in winter. Good ink ejection performance can be obtained.

That is, a drive voltage adjusted by a drive voltage adjusting circuit composed of a so-called series regulator is supplied to a drive circuit for driving a plurality of piezoelectric elements provided in the recording head. For example, the drive voltage adjusting circuit 100 shown in FIG. 10 will be described. An input terminal d to which an input voltage Vi from a power supply circuit is applied and an output terminal e that outputs an output voltage Vo as a drive voltage to a drive circuit (not shown). The voltage line L100 having
100 is interposed, and two voltage dividing resistors R120 and R121 for detecting the output voltage Vo are connected.

On the other hand, a transistor T1 connected in series is provided between the voltage line L100 and the voltage dividing line L101.
01 and a resistor R101, a circuit including a transistor T102 and a resistor R102 connected in series,
A circuit including a transistor T103 and a resistor R103 connected in series is connected in parallel with the voltage dividing resistor R120. Further, the voltage division of the voltage dividing line L101 is applied to one input terminal of the error amplification circuit (differential amplifier) 122 whose output terminal is connected to the base of the transistor T100, and the other input terminal is The reference voltage Vr from the reference power source E100 is applied.

By the way, a control terminal a connected to the base of the transistor T101, a control terminal b connected to the base of the transistor T102, and a transistor T103.
A control signal A, a control signal B, and a control signal C output from a control device (not shown) are respectively supplied to the control terminal c connected to the base of the. That is, these 3
When the two control signals A to C are at the “L” level, the transistors T101 to 103 are not conductive, so that the voltage dividing resistance value between the voltage line L100 and the voltage dividing line L101 is the resistance value of the voltage dividing resistor R120, and the output Voltage (driving voltage)
Although a predetermined voltage is output as Vo, when the control signals A to C are sequentially switched to the “H” level, these resistors R101 to 103 become parallel resistors with respect to the voltage dividing resistor R120, and the voltage line L100. And partial pressure line L1
Since the voltage division ratio between 01 and O becomes smaller and the divided voltage of the divided line L101 becomes larger than the reference voltage Vr, the output voltage from the error amplification circuit 122 is the difference voltage between these divided voltage and the reference voltage Vr. It becomes small so as to be eliminated, and a lower output voltage Vo is output as a drive voltage.

Next, the simple drive voltage adjusting circuit 200 shown in FIG. 11 will be described. An input terminal f to which an input voltage Vi from a power supply circuit is applied and an output voltage Vo as a drive voltage to a drive circuit not shown. The voltage line L200 having an output terminal g for outputting
And two voltage dividing resistors R220 and R221 for detecting the output voltage Vo are connected. Further, the divided voltage of the voltage dividing line L201 is applied to one input terminal of the error amplification circuit (differential amplifier) 222 whose output terminal is connected to the base of the transistor T200. By the way, the D / A converter 230 is added to the CPU 230a.
Since the 1-chip CPU 230 provided with b outputs the reference voltage adjustment data KAD corresponding to the temperature of the print head to the D / A converter 230b, the D / A converter 230b outputs the reference voltage adjustment data KAD. The corresponding reference voltage Vr is applied to the other input terminal of the error amplification circuit 222.

That is, when the reference voltage adjustment data KAD is changed and the reference voltage Vr becomes smaller, the output voltage from the error amplifier circuit 222 eliminates the difference voltage between the divided voltage and the reference voltage Vr. It becomes smaller and a lower output voltage Vo is output as the drive voltage. On the other hand, when the reference voltage adjustment data KAD is changed and the reference voltage Vr becomes large, the output voltage from the error amplification circuit 222 becomes large so as to eliminate the difference voltage between these divided voltage and the reference voltage Vr. , A higher output voltage Vo is output as the drive voltage.

[0008]

As described above, as shown in FIG.
In the general drive voltage adjusting circuit 100 shown in 0,
Since the circuit for adjusting the divided voltage by combining a plurality of transistors and resistors is provided, the drive voltage adjusting circuit 100
However, there is a problem in that the drive voltage adjusting circuit 100 is expensive because the precision of the circuit configuration is required to be high for a large number of these resistors.

Therefore, in the simple drive voltage adjusting circuit 200 shown in FIG.
Although the drive circuit itself is simplified, this drive voltage adjusting circuit 20
One chip C for supplying a reference voltage Vr that can be changed to 0
The PU 230 is required to have a D / A converter 230b with high conversion accuracy, but D with high conversion accuracy is required.
As the 1-chip CPU 230 equipped with the A / A converter 230b, the 1-chip CPU 230 that outputs the changeable reference voltage Vr is available because there are few types that are commercialized and it is expensive.
There is a problem that the cost of the PU 230 becomes high.

An object of the present invention is to provide a simple circuit for generating and smoothing a reference voltage adjusting pulse corresponding to the reference voltage adjusting data according to the detected temperature of the recording head, and outputting the reference voltage to the drive voltage adjusting circuit. It is an object of the present invention to provide a recording head drive voltage adjustment device for an inkjet recording device that can change

[0011]

According to another aspect of the present invention, there is provided a recording head drive voltage adjusting apparatus for an ink jet recording apparatus, wherein a drive voltage for driving a recording head of an ink jet recording apparatus for ejecting ink from an ejection nozzle to perform recording is at a predetermined ratio. In a recording head drive voltage adjustment device equipped with a drive voltage adjustment circuit that adjusts the drive voltage so that the difference voltage between the divided voltage divided by and the reference voltage is eliminated, the temperature of the print head is detected directly or indirectly. The temperature detecting means for storing the reference voltage temperature characteristic preset by associating the temperature of the recording head with the reference voltage adjustment data, and applying the detected temperature received from the temperature detecting means to the reference voltage temperature characteristic as the detected temperature. Adjustment data generating means for outputting the corresponding reference voltage adjustment data,
A pulse signal generator which receives the reference voltage adjustment data output from the adjustment data generating means and generates a reference voltage adjustment pulse signal having a pulse width or the number of pulses corresponding to the reference voltage adjustment data at predetermined intervals ; Received from signal generator
The reference photoelectrically digit reference voltage adjustment pulse signal with a flat smoothed
And a smoothing circuit for outputting a reference voltage having a magnitude corresponding to the pressure adjusting pulse signal to the drive voltage adjusting circuit.

The operation will be described. Since the temperature detecting means directly or indirectly detects the temperature of the recording head, the temperature of the recording head and the reference voltage adjustment data are associated with each other so that the reference voltage temperature characteristic is set in advance. The stored adjustment data generation means applies the detected temperature received from the temperature detection means to the reference voltage temperature characteristic and outputs reference voltage adjustment data according to the detected temperature. Then, the pulse signal generator receives the reference voltage adjustment data output from the adjustment data generating means, and responds to the reference voltage adjustment data every predetermined period.
Since generating a pulse signal for reference voltage adjustment of the pulse width or pulse number, the smoothing circuit, the reference voltage regulating the <br/> reference voltage adjustment pulse signal received from the pulse signal generator smoothes
A reference voltage having a magnitude corresponding to the adjustment pulse signal is output to the drive voltage adjustment circuit. As a result, the drive voltage adjustment circuit
The drive voltage is adjusted so as to eliminate the difference voltage between the divided voltage obtained by dividing the drive voltage for driving the recording head at a predetermined ratio and the reference voltage.

According to a second aspect of the present invention, there is provided a recording head drive voltage adjusting apparatus for an ink jet recording apparatus, wherein the pulse signal generator has a clock pulse generating circuit for generating a clock pulse, and the clock pulse generating circuit. A control pulse generation circuit that receives the clock pulse train from the reference voltage adjustment data and the reference voltage adjustment data, and outputs a control pulse signal having a pulse width corresponding to the data value of the reference voltage adjustment data every time a predetermined number of clock pulses are generated. An output circuit for converting the pulse amplitude of the control pulse signal received from the control pulse generating circuit into a predetermined amplitude to generate a reference voltage adjusting pulse signal.

Explaining the operation, the same operation as in claim 1 is achieved, but in the pulse signal generator, the clock pulse generating circuit generates the clock pulse.
The control pulse generation circuit receives the clock pulse train from the clock pulse generation circuit and the reference voltage adjustment data, and generates a control pulse signal having a pulse width corresponding to the data value of the reference voltage adjustment data to generate a predetermined number of clock pulses. The control circuit generates a reference voltage adjusting pulse signal by converting the pulse amplitude of the control pulse signal received from the control pulse generating circuit into a predetermined amplitude.

According to a third aspect of the present invention, there is provided a recording head drive voltage adjusting apparatus for an ink jet recording apparatus, wherein the pulse signal generator has a clock pulse generating circuit for generating a clock pulse, and the clock pulse generating circuit. A control pulse generation circuit that receives the clock pulse train from the reference voltage adjustment data and the reference voltage adjustment data, and outputs a control pulse signal of a pulse number according to the data value of the reference voltage adjustment data every time a predetermined number of clock pulses are generated. An output circuit for converting the pulse amplitude of the control pulse signal received from the control pulse generating circuit into a predetermined amplitude to generate a reference voltage adjusting pulse signal.

Explaining the operation, the same operation as in claim 1 is achieved, but in the pulse signal generator,
Since the clock pulse generation circuit generates the clock pulse, the control pulse generation circuit receives the clock pulse train from this clock pulse generation circuit and the reference voltage adjustment data, and outputs the pulse number corresponding to the data value of the reference voltage adjustment data. The control pulse signal is output each time a predetermined number of clock pulses are generated, and the output circuit converts the pulse amplitude of the control pulse signal received from the control pulse generation circuit into a predetermined amplitude to generate the reference voltage adjusting pulse signal. Occur.

According to a fourth aspect of the present invention, there is provided a recording head drive voltage adjusting device for an ink jet recording device, which is configured to eject ink from an ejection nozzle.
The recording head of an inkjet recording device that ejects and records
And the divided voltage obtained by dividing the drive voltage for driving
Adjust the drive voltage so that the reference voltage difference is eliminated
Recording head drive voltage adjusting device having drive voltage adjusting circuit
At the recording head temperature directly or indirectly
Output temperature detection means, recording head temperature and reference voltage adjustment
Preset reference voltage temperature characteristics in association with adjustment data
The reference temperature is stored as
Apply to temperature characteristics and adjust the reference voltage according to the detected temperature.
Adjustment data generating means for outputting
The reference voltage adjustment data output from the
For reference voltage adjustment corresponding to reference voltage adjustment data for each period
A pulse signal generator that generates a pulse signal and a pulse signal
Smooths the reference voltage adjustment pulse signal received from the generator.
Of the magnitude corresponding to the pulse signal for adjusting the reference voltage
A smoothing circuit for outputting a quasi-voltage to the drive voltage adjusting circuit,
The pulse signal generator includes a clock pulse generation circuit that generates a clock pulse, a clock pulse train from the clock pulse generation circuit, and reference voltage adjustment data, and the data value of the reference voltage adjustment data is a predetermined value or less. In the case of, a control pulse signal having a pulse number corresponding to the data value is formed, and when the data value is larger than a predetermined value, a pulse signal having a pulse width corresponding to the data value and a predetermined number of pulse trains are ORed. A control pulse generation circuit that outputs a control pulse signal each time a predetermined number of clock pulses are generated, and a pulse voltage for reference voltage adjustment by converting the pulse amplitude of the control pulse signal received from this control pulse generation circuit into a predetermined amplitude. And an output circuit for generating.

Explaining the operation, the same operation as in claim 1 is achieved, but in the pulse signal generator,
Since the clock pulse generation circuit generates a clock pulse, the control pulse generation circuit receives the clock pulse train from this clock pulse generation circuit and the reference voltage adjustment data, and when the data value of the reference voltage adjustment data is equal to or less than the predetermined value. , A control pulse signal of a pulse number according to the data value, and when the data value is larger than a predetermined value,
A control pulse signal composed of a logical sum of a pulse signal having a pulse width corresponding to the data value and a predetermined number of pulse trains is output every time a predetermined number of clock pulses are generated, and the output circuit outputs the control pulse generation circuit. The pulse amplitude of the control pulse signal received from is converted into a predetermined amplitude to generate a reference voltage adjusting pulse signal.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The present embodiment is a case where the present invention is applied to an ink jet recording apparatus that ejects ink contained in a detachably mounted ink cartridge from a recording head to print on recording paper. First, the inkjet recording apparatus 1 will be described. As shown in FIG. 1, basically, a platen 10, a carriage drive mechanism 20 for driving a carriage 21, and an ink cartridge are mounted on a main body frame 3 provided in a main body cover 2. An ink ejection mechanism 30 for ejecting the recording ink contained in the recording paper P to the recording paper P is provided.

The rubber platen 10 is shown in FIGS.
As shown in FIG. 3, the platen shaft 11 is disposed in the left-right direction, and the platen shaft 11 is rotatably supported by the side wall plates 3a and 3c of the main body frame 3 at both left and right ends.
A platen gear 12 is attached to the left end of the. A composite gear 13 having a first gear 14 that meshes with the platen gear 12 and a second gear 15 is rotatably supported by the side wall plate 3c, and a drive gear 16 that meshes with the second gear 15 feeds. It is attached to the motor 17. That is, the feed motor 17 is driven in a predetermined rotation direction and the drive gear 16 rotates, whereby the composite gear 13
The platen 10 is rotationally driven in a predetermined paper feeding direction via the platen gear 12 and the platen gear 12.

Next, regarding the carriage drive mechanism 20,
A description will be given based on FIGS. 1 and 2. A carriage 21 is horizontally arranged on the front side of the platen 10, and the carriage 21 is arranged at its rear end portion in parallel with the platen 10 and supported by the body frame 3.
Is supported by the guide rail portion 3d at the front end of the main body frame 3 so as to be movable in the left and right directions.

On the other hand, a driven pulley 23 is rotatably supported by the side wall plate 3b at the left end of the moving range of the carriage 21, and a carriage drive motor 25 comprising a DC motor is provided at the right end thereof. An endless timing belt 26 is stretched over a drive pulley 24 and a driven pulley 23 attached to the drive shaft of the carriage drive motor 25, and is connected to the timing belt 26 at the lower end of the carriage 21. There is. When the carriage drive motor 25 is rotationally driven, the carriage 21 is supported by the guide rod 22 and the guide rail portion 3d through the pulleys 23 and 24 and the timing belt 26, and the printing direction ( It is driven to reciprocate in the right direction) and in the opposite printing direction (left direction). The printing may be performed in both directions (left and right directions).

Next, the ink ejecting mechanism 30 for ejecting ink on the recording paper P to print will be described with reference to FIGS. 1 and 2. On the carriage 21, a box-shaped head holder 31 having an open upper part and a front part is mounted. A recording head 3 for ejecting ink, in which a plurality of ejection nozzles are formed on a standing wall portion 31a of the head holder 31.
2 is provided, and the recording head 32 is provided with a connecting cylinder portion 33 which is integrally formed by inserting the standing wall portion 31a. Here, inside the recording head 32, a plurality of ink supply passages (not shown) corresponding to a plurality of ejection nozzles are provided.
And a piezoelectric element (see FIG. 3) for ejecting ink is provided in each ink supply passage.

The ink cartridge 40 containing the ink absorber 41 containing the recording ink is removably mounted on the head holder 31, and the front end of the connecting cylinder 33 is formed on the ink cartridge 40. It is configured to come into contact with the ink absorber 41 through a supply port (not shown). As a result, the ink cartridge 4
The ink of 0 is supplied to the plurality of ink supply passages of the recording head 32 through the connecting cylinder portion 33, and the piezoelectric elements are driven, so that the ink is ejected from the ejection nozzles of the recording head 32 to print on the recording paper P. To be done.

Next, the control system of the ink jet recording apparatus 1 is constructed as shown in the block diagram of FIG. The first control unit 50 outputs a jet drive signal for executing ink jet from a plurality of jet nozzles, and a print control circuit 50a.
And an analog detected temperature input from a temperature sensor (corresponding to a temperature detecting means) 52 attached to the recording head 32, is converted into a digital detected temperature signal Ts, and the second control unit 5 is operated.
7, a temperature detection circuit 50b for outputting to the peripheral input / output interface 57b, a pulse signal generator 50c, and a smoothing circuit 50d. These print control circuit 50a, temperature detection circuit 50b, pulse signal generator 50c, and smoothing circuit 5 are provided.
0d is configured as a so-called application-specific integrated circuit (ASIC), which is a hard logic circuit.

The print control circuit 50a is connected to a head drive circuit 51 for driving the recording head 32, and the head drive circuit 51 includes a drive voltage adjusting circuit 5 which will be described later.
A drive voltage is supplied from 3. Furthermore, the first control unit 50
Is connected to a second control unit 57 via a bus 54 such as a data bus.
And the bus 54 has a ROM 55
A RAM 56 is connected.

The ROM 55 has various control programs for controlling image recording, and the recording head 3 as shown in FIG.
The reference voltage temperature characteristic map for obtaining the data value of the reference voltage adjustment data KAD corresponding to the temperature of 2 is stored, and the detected temperature signal Ts received from the temperature detection circuit 50b is applied to the reference voltage temperature characteristic map. An adjustment data generation control program for outputting the data value of the reference voltage adjustment data KAD according to the detected temperature signal Ts is stored. Further, the RAM 56 is provided with an image data memory for storing the received image data, various memories and buffers necessary for image recording.

Next, the second control unit 57 will be described. The second control unit 57 is a one-chip unit equipped with a peripheral input / output interface for performing image processing on the received image data and controlling various peripheral circuits. CPU, CPU
57a and a peripheral input / output interface 57b which is a so-called programmable peripheral interface (PPI).

The peripheral input / output interface 57b has a carriage drive circuit 58 for driving the carriage drive motor 25, a drive circuit 59 for driving the feed motor 17, a power switch, various switches and a display. An operation panel 60 provided with a lamp, and a paper sensor 61 for detecting the presence or absence of the recording paper P and the position of the leading edge thereof.
And an origin position detection sensor 62 for detecting the origin position of the carriage 21, and a communication interface 63 capable of receiving image data transmitted from an external electronic device 64 such as a host computer. There is. Here, the ROM 55 and the second control unit 57 correspond to adjustment data generating means.

Next, the pulse signal generator 50c, the smoothing circuit 50d, and the drive voltage adjusting circuit 53 will be described with reference to FIG. First, the pulse signal generator 50c will be described. The pulse signal generator 50c includes a clock pulse generation circuit 70, a control pulse generation circuit 71, and an output circuit 72. The clock pulse generation circuit 70 generates a clock pulse having a predetermined frequency, for example, 1 MHz (megahertz) and supplies it to the control pulse generation circuit 71.

The control pulse generating circuit 71 receives the clock pulse train from the clock pulse generating circuit 70, receives the reference voltage adjustment data KAD from the second controller 57, and receives the clock pulse train corresponding to the reference voltage adjustment data value. While the control pulse signal CP having the pulse width that is set to the “H” level is generated only while counting the “1”, the control pulse signal CP is output every time a predetermined number (for example, “1000”) of clock pulses are generated. Output to the circuit 72. For example, as shown in FIG. 6, when the reference voltage adjustment data value “100” is received, the “H” level control pulse signal CP100 counts 1000 clock pulse trains only while counting 100 clock pulse trains. It is repeatedly output every cycle T1.

Further, the output circuit 72 repeatedly receives the control pulse signal CP from the control pulse generating circuit 71, and converts the amplitude of the control pulse signal CP into the amplitude defining voltage Vc (for example, about 5V). The reference voltage adjusting pulse signal APS is sequentially output to the smoothing circuit 50d. Next, the smoothing circuit 50d will be described. The smoothing circuit 50d is a filter circuit including a resistor R5 and a capacitor C5.
The time constant of the capacitor C5 and the capacitor C5 is set to a large value. That is, by repeatedly receiving the reference voltage adjusting pulse signal APS from the output circuit 72 every period T1, an output voltage obtained by smoothing the reference voltage adjusting pulse signal APS is output, and the output voltage is output. Is supplied as the reference voltage Vr. Here, the output voltage, that is, the reference voltage Vr, is a smooth voltage that is substantially equal to (5V × reference voltage adjustment data value) / the number of clock pulses (1000) of the period T1.

Next, the drive voltage adjusting circuit 53 will be described. A transistor T10 is interposed in a voltage line L10 having an input terminal m to which an input voltage Vi from a power supply circuit (not shown) is applied and an output terminal n that outputs an output voltage Vo as a drive voltage to the head drive circuit 51. And two voltage dividing resistors R for detecting the output voltage Vo
10, R11 are connected. Furthermore, the transistor T
The voltage dividing line L1 is connected to one input terminal of an error amplifier circuit (differential amplifier) 75 whose output terminal is connected to the base of 10.
While the divided voltage of 1 is applied, the reference voltage Vr output from the smoothing circuit 50d is applied to the other input terminal.

That is, when the data value of the reference voltage adjustment data KAD is changed and the reference voltage Vr becomes smaller,
The output voltage from the error amplification circuit 75 becomes small so as to eliminate the difference voltage between the divided voltage of the divided line L11 and the reference voltage Vr, and a lower output voltage Vo is output as the drive voltage. On the other hand, when the data value of the reference voltage adjustment data KAD is changed and the reference voltage Vr becomes large, the output voltage from the error amplifier circuit 75 eliminates the difference voltage between the divided voltage and the reference voltage Vr. The output voltage Vo becomes higher and a higher output voltage Vo is output.

Here, in the control system of the ink jet recording apparatus 1 shown in FIG. 3, the recording head drive voltage adjusting apparatus includes a temperature sensor 52 for directly detecting the temperature of the recording head 32, a second control section 57, It comprises a ROM 55, a pulse signal generator 50c, a smoothing circuit 50d, a drive voltage adjusting circuit 53, and the like. Next, the operation of the recording head drive voltage adjusting device will be described with reference to FIGS. During the recording operation by the recording head 32, when one line is printed, or every time the printing process for one page is completed, the second controller 57 uses the temperature detection signal Ts output from the temperature detection circuit 50b as a reference. Voltage-temperature characteristic map (Fig. 4
The reference voltage adjustment data KAD corresponding to the detected temperature signal Ts is output to the control pulse generation circuit 71.

The control pulse generating circuit 71 receives the clock pulse train from the clock pulse generating circuit 70, and controls the pulse width to be "H" level only while counting the clock pulse train corresponding to the reference voltage adjustment data value. Each time the pulse signal CP is generated and a predetermined number (for example, “1000”) of clock pulses are received, the control pulse signal CP is repeatedly output to the output circuit 72. For example, as shown in FIG. 6, when the reference voltage adjustment data value is "100", the "H" level control pulse signal CP100 is repeatedly output every cycle T1 only while counting 100 clock pulse trains. .

Similarly, the reference voltage adjustment data value is "2.
00 ”, the control pulse signal CP200 indicates the cycle T
When the reference voltage adjustment data value is “300”, the control pulse signal CP300 is repeatedly output every cycle T1. When the reference voltage adjustment data value is “400”, the control pulse signal CP400 is output. Is repeatedly output every cycle T1 and the reference voltage adjustment data value is “500”, the control pulse signal CP500
Is repeatedly output every cycle T1, and when the reference voltage adjustment data value is “600”, the control pulse signal CP60
0 is repeatedly output every cycle T1 and the reference voltage adjustment data value is “700”, the control pulse signal CP7
00 is repeatedly output every cycle T1 and the reference voltage adjustment data value is “800”, the control pulse signal CP
When the reference voltage adjustment data value is "900", 800 is repeatedly output every cycle T1, and the control pulse signal C
P900 is repeatedly output every cycle T1. When the reference voltage adjustment data value is "1000", the "H" level signal is continuously output.

Then, in the output circuit 72, the amplitude of the control pulse signal CP received from the control pulse generating circuit 71 is converted so as to become the amplitude regulation voltage Vc (for example, about 5 V), and the reference voltage adjusting pulse signal APS is obtained. Is the smoothing circuit 50
It is output to d. Then, in the smoothing circuit 50d,
An output voltage obtained by smoothing the reference voltage adjusting pulse signal APS repeatedly received in each cycle T1 over a plurality of cycles T1 is output as the reference voltage Vr. For example, as shown in FIG. 7, when the reference voltage adjustment data value is "500" (control pulse signal CP500), the reference voltage Vr is about "2.5".
"V and the reference voltage adjustment data value is" 100 ".
When it is "0", the reference voltage Vr is about "5" V.

Then, in the drive voltage adjusting circuit 53, as described above, the error amplifying circuit 75 compares the divided voltage of the voltage dividing line L11 with the reference voltage Vr output from the smoothing circuit 50d to obtain the reference voltage. When the voltage Vr becomes small, the output voltage from the error amplification circuit 75 becomes small so as to eliminate the difference voltage between the divided voltage and the reference voltage Vr, and a lower output voltage Vo is output as the drive voltage. On the other hand, when the reference voltage Vr becomes large, the output voltage from the error amplification circuit 75 becomes large so as to eliminate the difference voltage between these divided voltage and the reference voltage Vr, and a higher output voltage Vo is output. .

As a result, when the temperature of the recording head 32 becomes lower as the outside air temperature becomes lower, the reference voltage Vr supplied to the drive voltage adjusting circuit 53 is changed by the reference voltage adjustment data KAD having a large data value. Becomes large, a large driving voltage is supplied to the piezoelectric element of the recording head 32, and even when the viscosity of the ink becomes high as the outside air temperature decreases, the large ink ejection force
In particular, good ink ejection performance can be obtained even in winter.

Thus, from the reference voltage adjustment data KAD corresponding to the detected temperature of the recording head 32, a control pulse signal CP having a pulse width corresponding to the reference voltage adjustment data KAD is generated, and every predetermined period T1 for counting a predetermined number of clock pulses. The reference voltage adjusting pulse signal APS is generated by converting the pulse amplitude of the control pulse signal CP into a predetermined amplitude, and the reference voltage Vr obtained by smoothing the reference voltage adjusting pulse signal APS is output to the drive voltage adjusting circuit. Since it outputs to 53, an expensive D / A converter that requires high conversion accuracy is not required, and these pulse signal generators and smoothing circuits for generating the variable reference voltage Vr are simple and inexpensive. It can be composed of a hard logic circuit.

Next, the first modification will be described. By the way, in the above embodiment, the pulse signal generation circuit 5
The control pulse generation circuit 71 for 0c may be modified to generate the control pulse signal CPA as shown in FIG. That is, the number of pulses corresponding to the data value of the reference voltage adjustment data KAD received from the second control unit 57 after receiving the clock pulse from the clock pulse generation circuit 70 (the duty of each pulse is the same as the clock pulse is 50% duty).
Control pulse signal CPA is generated, and the control pulse signal CPA is repeatedly output every period T2 for counting, for example, 1000 clock pulse trains.

For example, the reference voltage adjustment data value is "10.
When it is "0", the control pulse signal CPA100 consisting of 100 pulses is repeatedly output every cycle T2,
Similarly, when the reference voltage adjustment data value is "200", the control pulse signal CPA2 including 200 pulses is used.
00 is repeatedly output every cycle T2, and when the reference voltage adjustment data value is "300", the control pulse signal CPA300 consisting of 300 pulses is repeatedly output every cycle T2. Also in this case, the same operation and effect as those of the above-described embodiment can be obtained. However, the reference voltage Vr output by this first modification is a lower voltage than that in the above-described embodiment, and for example, the control pulse signal C
If the duty of each pulse of PA is 50%, about half the reference voltage Vr is output. Therefore, when it is desired to obtain the same output voltage Vo as in the above embodiment, the resistance values of the voltage dividing resistors R10 and R11 may be adjusted accordingly or the amplitude regulation voltage Vc may be increased.

Next, the second modification will be described. Further, the control pulse generation circuit 7 of the pulse signal generation circuit 50c
1 to change the control pulse signal CPB as shown in FIG.
May be generated. That is, the second control unit 5
The data value of the reference voltage adjustment data KAD received from 7 is "5.
00 "or less, the control pulse signal CPB having the number of pulses (the duty of each pulse is 50% duty which is the same as the clock pulse) according to the data value of the reference voltage adjustment data KAD is generated, and the control pulse signal CPB is generated.
B is repeatedly output, for example, at every cycle T3 of counting 500 clock pulse trains. For example, when the reference voltage adjustment data value is "100", the control pulse signal CPB100 consisting of 100 pulses is repeatedly output in every cycle T3, and similarly, when the reference voltage adjustment data value is "200", 200 The control pulse signal CPB200 composed of individual pulses is repeatedly output every cycle T2.

On the other hand, when the data value of the reference voltage adjustment data KAD is larger than "500", a pulse signal having a pulse width corresponding to the reference voltage adjustment data value and a predetermined number, for example, "500" pulse trains (clock pulse Pulse train with the same duty of 50%) (Note that the logical sum here includes not only the case where two signals are added by a logical sum circuit, but also the case where a logical sum is obtained as a result) The control pulse signal CPB is generated, and the control pulse signal CPB is repeatedly output every period T3 for counting, for example, 500 clock pulse trains. For example, if the reference voltage adjustment data value is “50
In the case of “1”, the pulse width spanning “2” pulse trains corresponding to the data value, in other words, the duty 5
Assuming that the pulse train is 0%, a control pulse signal CPB5 that is a logical sum of a pulse signal having a pulse width corresponding to three times the pulse width of one pulse and "500" pulse trains.
01 (not shown) is repeatedly output every cycle T3,
Further, when the reference voltage adjustment value is "600", a pulse having a pulse width (a pulse width corresponding to 201 times one pulse of the pulse train) spanning "101" pulse trains corresponding to the data value "600" Control pulse signal CPB600 that is the logical sum of the signal and the "500" pulse train
Are repeatedly output every cycle T3.

Similarly, the reference voltage adjustment data value is "70".
When it is "0", it is "2" according to the data value "700".
Pulse width across 01 "pulse trains (1 of pulse train
Control signal CPB700, which is a logical sum of a pulse signal having a pulse width corresponding to 401 times the number of pulses) and "500" pulse trains, is repeatedly output every cycle T3. Then, the reference voltage adjustment data value is “1000”.
In the case of, the "H" level signal is continuously output. Also in this case, the same operation and effect as those of the above-described embodiment can be obtained.

It should be noted that the reference voltage adjustment data KAD can be created based on the detected temperature from the temperature sensor for detecting the outside air temperature, and the drive voltage adjustment circuit 53 can adjust the output voltage Vo according to the reference voltage Vr. Of the clock pulse generation circuit 70, the frequency of the clock pulse generated by the clock pulse generation circuit 70 and the time constant of the smoothing circuit 50d are arbitrarily changed according to the smoothing condition, and a plurality of types of reference voltage temperature characteristic maps are stored. Various modifications are made to the above-described embodiment based on existing technology or technology obvious to those skilled in the art, such as selectively selecting and using it according to the temperature characteristics of the ink used and the environmental conditions of the installation location. It is possible. Further, it goes without saying that the present invention can be applied to a recording head drive voltage adjusting device of various inkjet recording devices capable of color printing.

[0048]

According to the recording head drive voltage adjusting device of the ink jet recording apparatus of the first aspect, the temperature detecting means, the adjustment data generating means, the pulse signal generator and the smoothing circuit are provided, and the recording head A reference voltage adjusting pulse signal having a pulse width or the number of pulses corresponding to the reference voltage adjusting data corresponding to temperature is generated at predetermined intervals, and the reference voltage adjusting pulse signal is smoothed. Since the generated reference voltage is output to the drive voltage adjustment circuit, an expensive D / A converter that requires high conversion accuracy is not required, and these pulse signal generators and smoothing circuits that generate changeable reference voltages are simple. In addition, it can be configured with an inexpensive circuit.

According to the recording head drive voltage adjusting device of the ink jet recording apparatus of the second aspect, the same effect as that of the first aspect can be obtained, but in the pulse signal generator, it corresponds to the data value of the reference voltage adjusting data. While outputting a control pulse signal with a pulse width every predetermined number of clock pulses,
Since the reference voltage adjusting pulse signal in which the pulse amplitude of the control pulse signal is converted into the predetermined amplitude is generated, the reference voltage adjusting pulse signal that can change the reference voltage can be easily generated, and as this pulse signal generator, It can be configured with a hard logic circuit, and the cost can be reduced.

According to the recording head drive voltage adjusting device of the ink jet recording apparatus of the third aspect, the same effect as that of the first aspect is obtained, but in the pulse signal generator, it corresponds to the data value of the reference voltage adjusting data. While outputting a control pulse signal of the number of pulses every predetermined number of clock pulses,
Since the reference voltage adjusting pulse signal in which the pulse amplitude of the control pulse signal is converted into the predetermined amplitude is generated, the reference voltage adjusting pulse signal that can change the reference voltage can be easily generated, and as this pulse signal generator, It can be configured with a hard logic circuit, and the cost can be reduced.

According to the recording head drive voltage adjusting device of the ink jet recording apparatus of the fourth aspect, the temperature detecting means.
, Adjustment data generating means, pulse signal generator, smoothing
A circuit is provided, and the same effect as that of claim 1 is provided, but in the pulse signal generator, a control pulse signal having a pulse number corresponding to the data value of the reference voltage adjustment data and a pulse having a pulse width corresponding to the data value are provided. A control pulse signal consisting of a logical sum of a signal and a predetermined number of pulse trains is output for each predetermined number of clock pulses, and a reference voltage adjusting pulse signal is generated by converting the pulse amplitude of this control pulse signal into a predetermined amplitude. Therefore, the reference voltage adjusting pulse signal capable of changing the reference voltage can be easily generated, and the pulse signal generator can be configured by the hard logic circuit, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a schematic perspective view of an inkjet recording apparatus according to an embodiment of the present invention.

FIG. 2 is a partial plan view of the inkjet recording apparatus.

FIG. 3 is a block diagram of a control system of the inkjet recording apparatus.

FIG. 4 is a diagram showing a reference voltage temperature characteristic map.

FIG. 5 is a circuit diagram of a pulse signal generator, a smoothing circuit, and a drive voltage adjusting circuit.

FIG. 6 is a diagram of a control pulse signal generated according to a reference voltage adjustment data value.

FIG. 7 is a diagram showing a relationship between a reference voltage adjustment data value and a reference voltage.

FIG. 8 is a view corresponding to FIG. 6 according to the first modification.

FIG. 9 is a view corresponding to FIG. 6 according to the second modification.

FIG. 10 is a circuit diagram of a drive voltage adjusting circuit according to a conventional technique.

FIG. 11 is a circuit diagram of a drive voltage adjusting circuit with a 1-chip CPU according to the related art.

[Explanation of symbols]

1 Inkjet recording device 42 recording head 50c pulse signal generator 50d smoothing circuit 52 Temperature sensor 53 Drive voltage adjustment circuit 57 second control unit 70 clock pulse generator 71 Control pulse generator 72 Output circuit

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/01 B41J 2/055

Claims (4)

(57) [Claims] 1. A driving voltage is applied so that a difference voltage between a divided voltage obtained by dividing a driving voltage for driving a recording head of an inkjet recording apparatus that ejects ink from an ejection nozzle for recording and a reference voltage is eliminated. In a recording head drive voltage adjusting device having a drive voltage adjusting circuit for adjusting, a temperature detecting means for directly or indirectly detecting the temperature of the recording head, and the temperature of the recording head and reference voltage adjustment data are associated with each other. Adjusting data generating means for storing the preset reference voltage temperature characteristic, applying the detected temperature received from the temperature detecting means to the reference voltage temperature characteristic, and outputting the reference voltage adjusting data according to the detected temperature; Receiving the reference voltage adjustment data output from the means, and adjusting the reference voltage of the pulse width or the number of pulses corresponding to the reference voltage adjustment data every predetermined period A pulse signal generator for generating a use pulse signal, and a flat smoothing the reference voltage adjustment pulse signal received from the pulse signal generator corresponding to the reference voltage adjustment pulse signal
A smoothing circuit that outputs a reference voltage of a magnitude to the drive voltage adjusting circuit, and a drive voltage adjusting device for a recording head of an inkjet recording apparatus, comprising: 2. The pulse signal generator receives a clock pulse generation circuit that generates a clock pulse, a clock pulse train from the clock pulse generation circuit, and reference voltage adjustment data, and outputs a data value of the reference voltage adjustment data. A control pulse generation circuit that outputs a control pulse signal with a corresponding pulse width each time a predetermined number of clock pulses are generated, and a pulse amplitude of the control pulse signal received from this control pulse generation circuit that is converted to a predetermined amplitude and used as a reference. The recording head drive voltage adjusting device for an inkjet recording apparatus according to claim 1, further comprising: an output circuit that generates a voltage adjusting pulse signal. 3. The pulse signal generator receives a clock pulse generation circuit that generates a clock pulse, a clock pulse train from the clock pulse generation circuit, and reference voltage adjustment data, and outputs a data value of the reference voltage adjustment data. A control pulse generation circuit that outputs a control pulse signal of a corresponding number of pulses each time a predetermined number of clock pulses are generated, and a pulse amplitude of the control pulse signal received from this control pulse generation circuit that is converted to a predetermined amplitude and used as a reference. The recording head drive voltage adjusting device for an inkjet recording apparatus according to claim 1, further comprising: an output circuit that generates a voltage adjusting pulse signal. 4. An ink jet is ejected from an ejection nozzle to record.
Drive that drives the recording head of an inkjet recording device
Voltage difference between the divided voltage obtained by dividing the voltage at a specified ratio and the reference voltage
Voltage adjustment circuit that adjusts the drive voltage so that
In a recording head drive voltage adjusting device having a head, the temperature of the recording head is detected directly or indirectly.
The temperature detecting means and the temperature of the recording head and the reference voltage adjustment data are associated with each other.
The preset reference voltage temperature characteristic is stored and the temperature is detected.
Apply the detected temperature from the means to the reference voltage temperature characteristic
The adjustment data that outputs the reference voltage adjustment data according to the detected temperature.
Data generating means and the reference voltage adjustment data output from the adjustment data generating means.
Data, the reference voltage adjustment data
Pulse signal for generating the corresponding reference voltage adjustment pulse signal
Generator and reference voltage adjusting pulse received from the pulse signal generator
Corresponds to the pulse signal for smoothing the signal and adjusting its reference voltage
Output a reference voltage of the magnitude to the drive voltage adjusting circuit.
The pulse signal generator includes a clock pulse generating circuit that generates a clock pulse, a clock pulse train from the clock pulse generating circuit, and reference voltage adjustment data, and receives the reference voltage adjustment data data. When the value is equal to or less than a predetermined value, a control pulse signal having a pulse number corresponding to the data value is generated. When the data value is greater than a predetermined value, a pulse signal having a pulse width corresponding to the data value and a pulse train having a predetermined number are generated. And a control pulse generation circuit that outputs a control pulse signal composed of a logical sum of every time a predetermined number of clock pulses are generated, and a pulse amplitude of the control pulse signal received from this control pulse generation circuit is converted into a predetermined amplitude to obtain a reference value. driving the recording head characteristics and to Louis inkjet recording apparatus further comprising an output circuit for generating a pulse signal for voltage regulation, the Dynamic voltage regulator.