JP2000203018A - PRINT HEAD VOLTAGE CONTROLLER AND COLOR INK JET PRINTER HAVING THE SAME - Google Patents

Abstract

[PROBLEMS] To enable each print head to be driven at a suitable print head drive voltage while reducing cost and size. SOLUTION: Each print head voltage control circuit 50C, 50.
M, 50Y, 50K are the print head drive circuit heads 3
The second voltage control is performed while individually correcting the output voltages of 0C, 30M, 30Y, and 30K, that is, the print head drive voltages Vpc, Vpm, Vpy, and Vpk, to each of the print head voltage control circuits 50. The variable output voltage supply circuit 60 that supplies the source voltage V1 outputs the output voltage (V
1) to the respective highest values of the driving voltages V2c, V2m, V2y, V2k supplied to the respective print head drive circuits 30 by the second voltage control of the respective print head voltage control circuits 50. The first voltage control is performed so as to be equal to or greater than the absolute maximum voltage value which is the absolute maximum value among the total sum maximum voltage values obtained by adding the voltage drop amounts of the above.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a print head voltage control device for controlling a drive voltage of a print head and a color ink jet printer having the same.

[0002]

2. Description of the Related Art In FIG.
The print head voltage control device for adjusting (controlling) the print head drive voltage Vp of 0 includes a print head voltage control circuit 60 of a variable output voltage type and a print head drive circuit 30. The temperature detecting means 25 includes a print head 40.
Is detected directly or indirectly, and the detected temperature signal T
Is output to the drive control unit 20.

The drive control unit 20 obtains print data D, temperature correction data, and set voltage data from the CPU 11, outputs the print data D to the print head drive circuit 30, and responds to the input set voltage data. In addition, a set voltage signal S corrected using the detected temperature signal T and the temperature correction data is output to the print head voltage control circuit 60.

The print head voltage control circuit 60 receives an AC power supply as an input and generates a DC power supply (drive voltage V) corresponding to the set voltage signal S and outputs the DC power supply to the print head drive circuit 30 by, for example, a switching method.

[0005] The print head drive circuit 30 outputs the print data D
Are driven by a print head drive voltage Vp equal to the drive voltage V (eg, a thermal element, a dot pin, an ink jet nozzle, etc.) of the print head 40 corresponding to. That is, printing is performed.

[0006] The printer control unit 10 includes a CPU 1
1, a memory 12, a paper feeding motor 13 and a communication interface (I / F). The temperature correction data can also be output to the drive control unit 20.

[0007]

Some printers have a plurality of print heads 40, such as a color ink jet printer. In such a printer, as in the trial example 1 shown in FIG. Drive circuit 30 (30C, 30M, 3
0Y, 30K), and print heads 40C,
When the 40M, 40Y, and 40K are configured to be drivable, only one set voltage signal S can be input in common because the print head voltage control circuit 60 is a common one. That is, it is meaningless to individually feed back the detected temperature signals Tc, Tm, Ty, and Tk.

Therefore, the properties (characteristics) of the color inks for each color are different, there are variations in production, and the optimum printing operation temperature is also different. That is, if each color is driven with the same energization waveform (voltage, frequency, etc.), clear and high-quality printing cannot be performed. In particular, the print head 40 capable of gradation expression cannot perform subtle gradation expression.

Therefore, as shown in FIG.
0, the printhead voltage control circuit 6 for each color
It is conceivable to separately provide 0C, 60M, 60Y, and 60K. However, this trial example 2 is exactly the same as the case where four conventional examples shown in FIG. 5 are installed in parallel, so that the cost and the size of the printer are greatly increased.

A first object of the present invention is to provide a print head voltage control device capable of driving each print head at a suitable print head drive voltage while reducing cost and size. Another object of the present invention is to provide a color ink jet printer having a print head voltage control device and capable of performing clear and high-quality color printing.

[0011]

According to the first aspect of the present invention, each of the print heads includes a temperature correction, and each of the drive voltages is equal to each of the print head drive voltages by an individual second voltage control so as to be adjustable. In addition, the first voltage control common to each second voltage control can be executed on the upstream side of each second voltage control, and the first voltage control range is set to be larger than each second voltage control range. This is a head voltage control device which is set to be high and each drive voltage can be adjusted by two-stage voltage control.

In this invention, each print head is adjusted by performing the temperature correction on each drive voltage equal to each print head drive voltage by individual second voltage control, and the respective print heads are adjusted on the upstream side of each second voltage control. In addition, a first voltage control common to the respective second voltage controls is executed. This first voltage control range corresponds to each second voltage control range.
Is set higher than the voltage control range. That is, each print head drive voltage is adjusted by two-stage voltage control.

Therefore, each of the second voltage controls is performed by a dropper type print head voltage control circuit of a simple structure and inexpensive structure capable of outputting a print head drive voltage lower than the input voltage (drive voltage). The first voltage control can be configured to be performed by a voltage supply circuit formed from, for example, a switching power supply that generates a DC power supply from an AC power supply.

Thus, for example, each of the second voltage control ranges for four print heads is set to, for example, 15 to 18 V, 16 to
19 V, 17 to 20 V, 18 to 21 V, and the first voltage control can be performed at 19 to 25 V, for example, so that the power loss of each print head voltage control circuit can be minimized and relatively small. It is possible to use only one expensive and large-sized switching power supply unit. Therefore, it is possible to drive each print head with a suitable print head drive voltage while reducing cost and size.

According to a second aspect of the present invention, each print head is provided with a temperature detecting means, a print head voltage control circuit, and a print head drive circuit, and each print head voltage control circuit outputs each print head drive voltage. A voltage for supplying the original voltage to each of the print head voltage control circuits, while forming the drive voltage to be supplied to each of the print head drive circuits so as to perform the second voltage control while individually correcting the temperature. The supply circuit is of a variable output voltage type, and the output voltage of this voltage supply circuit is set to the maximum value of each drive voltage supplied to each print head drive circuit by the second voltage control of each print head voltage control circuit. The first voltage control can be performed by setting the absolute maximum voltage value which is the absolute maximum value among the total maximum voltage values obtained by adding the drop voltages of the respective print head voltage control circuits to the absolute maximum value. It formed a print head voltage controller.

In this invention, the output voltage variable voltage supply circuit supplies the original voltage to each of the print head voltage control circuits. In addition, each print head voltage control circuit performs the second voltage control while individually correcting the temperature of each drive voltage based on the supplied original power. Each drive voltage is equal to each printhead drive voltage.

Here, the output voltage of the voltage supply circuit is set to the maximum value of each drive voltage supplied to each print head drive circuit by the second voltage control of each print head voltage control circuit, and to the print head voltage of each print head voltage control circuit. The first voltage control is performed with the sum total voltage value obtained by adding the voltage drop of the control circuit being equal to or higher than the absolute maximum voltage value which is the absolute maximum value among them.

Therefore, each of the second voltage controls is performed by a dropper-type print head voltage control circuit of a simple and inexpensive structure capable of outputting a print head drive voltage lower than the input voltage (drive voltage). The first voltage control can be configured to be performed by a voltage supply circuit formed from, for example, a switching power supply that generates a DC power supply from an AC power supply.

Thus, for example, each of the second voltage control ranges for four print heads is set to, for example, 15 to 18 V, 16 to
19 V, 17 to 20 V, 18 to 21 V, and the first voltage control can be performed at 19 to 25 V, for example, so that the power loss of each print head voltage control circuit can be minimized and relatively small. It is possible to use only one expensive and large-sized switching power supply unit. Therefore, it is possible to drive each print head with a suitable print head drive voltage while reducing cost and size.

According to a third aspect of the present invention, the voltage supply circuit is formed of a switching power supply device that generates a DC power supply from an AC power supply, and each of the print head voltage control circuits controls the drive voltage lower than an input voltage. It is a dropper type print head voltage control device for outputting.

According to the invention, the switching power supply device forming the voltage supply circuit generates a DC power supply, that is, a main power supply, from the AC power supply. Each printhead voltage control circuit of the dropper system outputs each drive voltage lower than the input voltage (source power supply) due to the voltage drop action.

Therefore, in addition to providing the same operation and effect as the case of the second aspect of the invention, each print head voltage control circuit has a simple structure, is inexpensive and small, and minimizes each voltage drop. Power loss and heat generation can be reduced. Since one common switching power supply device and the voltage control range can be narrowed, the device cost can be further reduced and further downsizing can be achieved.

Further, according to a fourth aspect of the present invention, each of the print head voltage control circuits sets the respective drive voltages stored in the drive voltage table in accordance with the temperature environment of each of the print heads as a target value. This is a print head voltage control device that performs voltage control.

According to the present invention, each print head voltage control circuit performs the second voltage control with each drive voltage ranked in accordance with the temperature environment of each print head and stored in the drive voltage table as a target value. Therefore, in addition to providing the same operation and effect as in each of the first to third aspects of the present invention, each drive voltage stored in the drive voltage table is further applied to the characteristics and use environment of each print head. Since the value can be rewritten to a suitable value, a more optimal printing operation can be performed and the handling is simple.

According to a fifth aspect of the present invention, there is provided a color ink jet printer comprising the print head voltage control device according to any one of the first to fourth aspects, wherein each print head has an ink jet nozzle structure for each color. is there.

According to this invention, each print head having the ink jet nozzle structure for each color can perform color printing while jetting ink for each color using each print head drive voltage output from the print head voltage control device. it can. Therefore, the print head for each color can be driven by each print head drive voltage that matches the properties of each color ink, so that clear and high-quality color printing can be stably performed, and the cost and size of the entire printer are reduced. it can.

Further, the invention of claim 6 is a color ink jet printer capable of expressing gradation by changing the ink amount of each color to be jetted by the ink jet nozzle structure for each color.

In this invention, the ink jet nozzle structure of each print head changes the gradation expression by adjusting the drive voltage of each print head to change the ink amount of one dot jet from each color nozzle. Inkjet can be performed. In addition to providing the same functions and effects as the case of the invention of claim 5, color printing with higher gradation and higher image quality can be performed.

[0029]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1 and FIG. 2, the print head voltage control circuit 50 of the present print head voltage control circuit 50C, 50M, 50Y, 50K outputs the output voltage of the print head drive circuit heads 30C, 30M, 30Y, 30K, that is, the print voltages. Head drive voltages Vpc, Vpm, Vpy,
The second voltage control is performed while individually correcting the temperature of Vpk, and each print head voltage control circuit 50C, 50M, 50
The output voltage variable voltage supply circuit 60 that supplies the original voltage V1 to each of the Y and 50K outputs the output voltage (V1) by the second voltage control of each of the print head voltage control circuits 50C, 50M, 50Y, and 50K. Print head drive circuit 30
Drive voltage V2 supplied to C, 30M, 30Y, 30K
Absolute maximum, which is the absolute maximum value among the sum maximum voltage values obtained by adding the drop voltages of the print head voltage control circuits 50C, 50M, 50Y, and 50K to the highest values of c, V2m, V2y, and V2k. The first voltage control is performed when the voltage is equal to or higher than the voltage value.

The print head voltage control device of this embodiment is used as a voltage control device of a print head having a color ink jet nozzle structure of a color ink jet printer shown in FIG.

In FIG. 4, a print medium (paper or the like) rotates at a high speed (for example, 120
(rpm) and sent in the R direction. Print heads 40 (40C, 40M, 40Y, 4) for four colors (cyan, yellow, magenta, and black)
0K) has an ink-jet nozzle structure having a large number (for example, 2000) of ink-jet nozzles (not shown) arranged and arranged in the main scanning (X) direction, respectively, and has the same sub-scanning (Y) direction as the R direction. Are displaced.

Each of the print heads 40C, 40M, 40Y, 4
Each of the 0K ink jet nozzles can change (strength adjustment) the voltage value of each print head drive voltage Vpc, Vpm, Vpy, Vpk shown in FIG. 1 so that the amount of ink per dot jetted from each ink jet nozzle is adjusted. It is configured to be able to express gradations by changing.

The timing detecting means 5 comprises a slit disk 5D mounted on the shaft 2 and a transmission type detector 5S, and can detect the ink jet timing of each of the printing heads 40C, 40M, 40Y, 40K. .

Each print head 40C, 40M, 40Y, 4
In 0K, the respective color inks are supplied from respective ink supply means (not shown), and are formed so as to be printable on a print medium (paper or the like) wound around the drum 1 and sent in the R direction while inkjetting from a selected inkjet nozzle. Have been. In this embodiment, for example, color printing can be performed on A4 paper at a high speed of 20 PPM.

In FIG. 1, each temperature detecting means 25C, 2
5M, 25Y, and 25K correspond to the respective print heads 40.
The temperatures of C, 40M, 40Y, and 40K are directly (or indirectly) detected, and the respective temperature detection signals Tc, Tm, T
y and Tk are fed back to the drive control unit 20.

The printer controller 10 includes a CPU 11, a memory 12, a motor 13 for feeding paper and rotating a drum, and a communication interface (I / F), and controls the entire color ink jet printer. A drive voltage table 12T that stores drive voltages Vp (= V2) ranked according to the temperature environment of each print head 40 in the memory (Memory) 12.
1, 12T2, 12T3, and 12T4 are provided.

In this embodiment, the drive voltage table 12T1 for rank 1 includes a print head drive voltage Vpc (for example, 31 to 35 ° C.) with respect to the temperature for the print head 40C.
15V), and the drive voltage table 12T2 of rank 2 shows the print head drive voltage V with respect to the temperature for the print head 40M.
pm (for example, 36 to 40 ° C .... 17 V), a rank 3 drive voltage table 12T3 includes a print head drive voltage Vpy (for example, 41 to 45 ° C .... 19 V) with respect to the temperature for the print head 40Y, and a rank 4 drive voltage table. 12
At T4, a print head drive voltage Vpk (for example, 46 to 50 ° C.... 21 V) corresponding to the temperature for the print head 40K is stored. Each value is a value in consideration of manufacturing variations, ink properties, and the like, and the setting can be changed.

The printer control unit 10 can recognize each detected temperature (T) via the drive control unit 20, and extracts temperature correction data corresponding to the detected temperature (T), and
Can be output to The print data D is transferred from outside (for example, a host computer) via the interface.

The drive control unit 20 includes the printer control unit 10
(CPU 11) print data Dpc, Dpm, Dp
y, Dpk and drive voltage tables 12T1, 12T2,
Each temperature correction data and each set voltage data generated based on 12T3 and 12T4 are acquired and set in each register, and print data Dpc, Dpm, and Dpc are obtained.
py and Dpk to the respective print head drive circuits 30C and 30
M, 30Y, and 30K, corresponding to the input set voltage data, and detecting temperature signals Tc, Tm, Ty, T
k, the second set voltage signals S2c, S2m, S
2y and S2k are connected to the respective print head voltage control circuits 50C,
Output to 50M, 50Y, 50K.

Further, the drive control section 20 outputs the first set voltage signal S1 generated with reference to the second set voltage signals S2c, S2m, S2y, S2k to the voltage supply circuit 60.

Here, the voltage supply circuit 60 is formed of a switching power supply that generates a DC power supply from an AC power supply. This switching power supply includes a primary-side filter, a rectifier, a switching element, a voltage control circuit, a pulse transformer, a secondary-side smoothing capacitor,
It includes a voltage stabilizing circuit and the like, and generates and outputs a stable DC power supply (source voltage V1) corresponding to the first set voltage signal S1.

Each print head voltage control circuit 50C,
50M, 50Y, and 50K are dropper systems that output drive voltages V2c, V2m, V2y, and V2k that are lower than the input voltage (original voltage V1).

More specifically, the print head voltage control circuit 50
Is a digital / analog converter 51, as shown in FIG.
Including an operational amplifier 53 and a three-terminal regulator 52,
The driving voltage V2 corresponding to the input second set voltage signal S2 can be output. In principle, the voltage difference between the GND terminal and the OUT terminal is a fixed value (for example, 1.25
V). Also, the voltage of the IN terminal (V1)
Is formed so as to have a fixed voltage (for example, 1.5 V) or more higher than the voltage (V2) of the OUT terminal so as to obtain a stable output.

The digital / analog converter 51 receives the voltage value (second set voltage signal S 2) from the drive control section 20 in the form of serial data reception, converts it into an analog voltage signal, and outputs it to the operational amplifier 53. This operational amplifier 53
Has only the impedance conversion function with a gain of 1 in this embodiment.

On the other hand, the voltage supply circuit 60 controls the respective print head drive circuits 30C, 3C by the second voltage control of the respective print head voltage control circuits 50C, 50M, 50Y, 50K.
0M, 30Y, 30K, each driving voltage V2c,
V2m, V2y, V2k (eg, 18V,
19V, 20V, 21V) by the voltage drop (for example, fixed value, 1.5V, 1.5V, 1.5V, 1.5V) of each of the print head voltage control circuits 50C, 50M, 50Y, 50K.
V) (e.g., 19.5)
V, 20.5 V, 21.5 V, 22.5 V) so that the original voltage V1 can be output by performing the first voltage control at an absolute maximum voltage value (22.5 V) which is an absolute maximum value or more. Is set.

That is, each of the print heads 40C, 40M,
The print head drive voltages Vpc, Vp including the respective temperature corrections and the respective second printhead drive voltages 40Y, 40K are controlled by the individual second voltage control.
drive voltages V2c, V2 equal to m, Vpy, Vpk
2m, V2y, and V2k are formed so as to be adjustable, and a first voltage control common to each second voltage control can be executed on the upstream side of each second voltage control, and a first voltage control range. Are set higher than the respective second voltage control ranges, and the driving voltages V2c, V2m, V2y, V2k (= Vpc, Vpm,
Vpy, Vpk) can be adjusted by two-stage voltage control.

In this embodiment, the variable output voltage type voltage supply circuit 60
The set voltage signal S1 and the AC power supply (AC100V) are input to generate the original voltage V1, and supply the original voltage V1 to each of the print head voltage control circuits 50C, 50M, 50Y, and 50K.

Each print head voltage control circuit 50C,
50M, 50Y, and 50K are temperature-corrected second set voltage (drive voltage) signals S2c, S2m, and S2 based on the supplied original power supply V1 and input from the drive control unit 20.
y, S2k as target values, the respective drive voltages V2c, V2c
The second voltage control is individually performed for 2m, V2y, and V2k.

Here, each print head voltage control circuit 50
Each of C, 50M, 50Y, and 50K outputs a drive voltage lower than the input voltage (source power supply V) due to the voltage drop effect by the dropper method shown in FIG. Each drive voltage V2c, V2m, V
2y and V2k are the print head drive voltages Vpc and Vp
m, Vpy, equal to Vpk. Therefore, the structure is simple, inexpensive, and small, and each voltage drop can be minimized, so that power loss and heat generation can be reduced.

The output voltage (V1) of the voltage supply circuit 60 is
Each print head voltage control circuit 50C, 50M, 50Y, 5
The highest value of each of the drive voltages V2c, V2m, V2y, and V2k supplied to each of the print head drive circuits 30C, 30M, 30Y, and 30K by the second voltage control of 0K (for example, 15 to 18V, 16 to 19V, 17-20V, 18
To 21V) to the respective print head voltage control circuits 50C, 5C.
The sum total maximum voltage value (19.5 V, 20.5 V, 2
The voltage is adjusted by the first voltage control to a voltage (for example, 23 V) which is equal to or higher than an absolute maximum voltage value (22.5 V) which is an absolute maximum value among them (1.5 V, 22.5 V).

That is, each of the second voltage control ranges is, for example, 15 to 18 V, 16 to 19 V, 17 to 20 V, and 18 to 2 V.
Since the first voltage control can be performed at, for example, 23 to 26 V at 1 V, the power loss and heat generation of each of the print head voltage control circuits 50C, 50M, 50Y, and 50K can be minimized and compared. It is possible to use only one expensive and large switching power supply unit. Therefore, each of the print heads 40C, 40M, 40Y, and 40K is provided with a suitable print head drive voltage Vpc, Vpm, Vpy, Vp while reducing cost and miniaturization.
In addition to being able to drive at k, the voltage control range can be narrowed with one common switching power supply device, so that the cost of the device (printer) can be further reduced and further miniaturization can be achieved.

Moreover, each print head voltage control circuit 50
C, 50M, 50Y, and 50K perform the second voltage control with the respective drive voltages ranked and stored in the drive voltage tables 12T (1 to 4) input via the drive control unit 20 for each temperature environment as target values. Therefore, each driving voltage stored in the driving voltage table can be rewritten to a suitable value according to the characteristics of each print head and the use environment, so that more optimal printing operation can be performed and handling is simple.

The print heads 40C, 40M, 40
Even if Y and 40K have the inkjet nozzle structure for each color, the print head voltage control device (30C, 30M, 30
Y, 30K), and print head drive voltages Vpc, Vpm, Vpy, Vp for each ink jet nozzle.
Color printing can be performed while jetting ink for each color using k.

Therefore, the properties of each color ink (temperature / temperature)
Viscosity) and each print head 40C, 40M, 40Y, 40K
A color inkjet printer that can perform clear and high-quality color printing while completely correcting that the inkjet characteristics (ejection amount / ejection speed / ejection direction) change due to manufacturing variations (manufacturing accuracy, material, etc.) Further, cost reduction and further miniaturization can be promoted.

Further, the respective print head drive voltages V
By adjusting the intensity of pc, Vpm, Vpy, and Vpk to change the amount of ink for each color to perform an ink jet with different gradation expression, color printing with high gradation and high image quality can be performed.

[0056]

According to the first aspect of the present invention, each print head is formed so as to be capable of adjusting each drive voltage equal to each print head drive voltage by individual second voltage control including temperature correction, The first voltage control common to each second voltage control can be executed on the upstream side of each second voltage control. The first voltage control range is set higher than each second voltage control range, and each drive is performed. Since the head voltage control device is formed so that the voltage can be adjusted by two-stage voltage control, each print head can be driven at a print head drive voltage suitable for each while reducing costs and miniaturizing.

According to the second aspect of the present invention, each print head is provided with a temperature detecting means, a print head voltage control circuit, and a print head drive circuit, and each print head voltage control circuit is provided with each print head drive circuit. The second voltage control is performed while individually correcting the temperature of each drive voltage to be supplied to the print head, and the output voltage of the variable output voltage type voltage supply circuit that supplies the original voltage to each print head voltage control circuit is controlled by each print head voltage control. A first voltage equal to or more than an absolute maximum voltage value obtained by adding a drop voltage of each print head voltage control circuit to each highest value of each drive voltage supplied to each print head drive circuit by the second voltage control of the circuit; Since the print head voltage control device is formed so as to perform control, it is possible to drive each print head with a print head drive voltage suitable for each while reducing cost and size. .

According to the third aspect of the present invention, the voltage supply circuit is formed by the switching power supply device and each print head voltage control circuit is formed by the dropper system. In addition to the above advantages, each print head voltage control circuit has a simple structure, is inexpensive and small, and each voltage drop can be minimized, so that power loss and heat generation can be reduced.
Since one common switching power supply device and the voltage control range can be narrowed, the device cost can be further reduced and further downsizing can be achieved.

Further, according to the present invention, each print head voltage control circuit sets each print head to the second voltage control by setting each drive voltage ranked and stored in the drive voltage table for each temperature environment as a target value. Therefore, in addition to the effects similar to those of the first to third aspects of the present invention, each drive voltage stored in the drive voltage table can be used to determine the characteristics of each print head. Since it can be rewritten to a suitable value according to the usage environment,
More optimal printing operation is possible and handling is easy.

According to a fifth aspect of the present invention, there is provided a print head voltage control device according to any one of the first to fourth aspects, wherein each print head has an ink jet nozzle structure for each color and a color ink jet printer. Therefore, it is possible to drive the print head for each color with each print head drive voltage that matches the properties of each color ink and that is corrected for manufacturing variations. Therefore, clear and high-quality color printing can be stably performed, and the cost and size of the entire printer can be reduced.

Further, according to the invention of claim 6, since the ink jet nozzle structure for each color can change the amount of the ink for each color to be jetted, the gradation can be expressed, the same as in the invention of claim 5 In addition to the above effects, color printing with higher gradation and higher image quality can be performed.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an embodiment of the present invention.

FIG. 2 is a diagram for explaining a dropper type print head voltage control circuit.

FIG. 3 is a front view for explaining a drive voltage table.

FIG. 4 is a view for explaining a color ink jet printer.

FIG. 5 is a diagram for explaining a conventional print head voltage control device.

FIG. 6 is a diagram illustrating a trial example (1) of the print head voltage control device.

FIG. 7 is a diagram for explaining a trial example (2) of the print head voltage control device.

[Explanation of symbols]

Reference Signs List 1 drum (inkjet printer) 5 timing detecting means 10 control unit 20 drive control unit 30 printhead drive circuit 40 printhead (inkjet printer) 50 dropper type printhead voltage control circuit 60 voltage supply circuit of variable output voltage (switching power supply) Device) Dp Print data S1 First set voltage signal S2 Second set voltage signal V1 Original voltage V2 Drive voltage Vp Print head drive voltage

Claims (6)

[Claims] 1. A method according to claim 1, wherein each of the print heads includes a temperature correction, and each of the drive voltages is equal to each of the print head drive voltages by an individual second voltage control. And the first voltage control common to each second voltage control can be executed, the first voltage control range is set higher than each second voltage control range, and each drive voltage is set to 2
A print head voltage control device formed to be adjustable by step voltage control. 2. A print head drive circuit comprising: a temperature detection means, a print head voltage control circuit, and a print head drive circuit provided in each print head, and each print head drive voltage output by each print head voltage control circuit. And a voltage supply circuit for supplying an original voltage to each of the print head voltage control circuits while controlling the drive voltage to be supplied to each of the printheads while individually correcting the temperature. And the output voltage of this voltage supply circuit is set to the second voltage of each print head voltage control circuit.
The absolute maximum value of the sum total maximum voltage value obtained by adding the voltage drop of each print head voltage control circuit to the maximum value of each drive voltage supplied to each print head drive circuit by the voltage control of A printhead voltage control device formed so as to perform the first voltage control at a certain absolute maximum voltage value or more. 3. The printing apparatus according to claim 2, wherein the voltage supply circuit is formed of a switching power supply device that generates a DC power supply from an AC power supply, and each of the print head voltage control circuits is a dropper system that outputs the drive voltage lower than an input voltage. The printhead voltage control device according to claim 2. 4. Each of the print head voltage control circuits performs a second voltage control using the respective drive voltages stored and ranked in the drive voltage table according to the temperature environment of each print head as a target value. Claim 1 to Claim 3
The print head voltage control device according to any one of the preceding claims. 5. A color ink jet printer comprising the print head voltage control device according to claim 1, wherein each print head has an ink jet nozzle structure for each color. 6. The color ink jet printer according to claim 5, wherein the ink jet nozzle structure for each color can change the amount of ink for each color to be jetted to express gradation.