CN1876377A - Device and method for providing nozzle voltage of inkjet printer - Google Patents

Abstract

The invention provides a voltage supply device comprising a lookup table, a selection module and an adjustable voltage supply. The voltage supply device is used for matching a plurality of nozzles in an ink-jet printer. The ink jet printer is capable of providing a plurality of print modes, each print mode corresponding to a respective number of nozzles. The lookup table stores a plurality of sets of control signals corresponding to the respective printing modes. The selection module is used for receiving an instruction, and the instruction indicates that a user selects a printing mode from the printing modes as a final printing mode. The selection module selects a group of control signals corresponding to the final printing mode from the plurality of groups of control signals as a group of final control signals according to the instruction. The adjustable voltage supply provides a voltage to the nozzle according to the set of final control signals.

Description

Device and method for providing nozzle voltage of inkjet printer

technical field

The present invention relates to a voltage supply device, and to a voltage supply device for supplying inkjet head voltage of a printer.

Background technique

Thermal inkjet printer (thermal inkjet printer) is a kind of very common printer at present. Generally speaking, a monochrome inkjet printer includes one inkjet head for providing black ink, and a color inkjet printer further includes several inkjet heads for providing basic color ink. Each black or color inkjet head usually contains a plurality of nozzles. Most of the inkjet printers currently on the market provide a variety of different printing modes for users to choose; each printing mode corresponds to a different resolution and printing quality. Depending on the resolution setting, the number of nozzles used for each print will change accordingly. That is to say, according to the printing mode selected by the user, the printer controls different nozzles to be turned on or off each time printing is performed. The tiny ink droplets ejected from each nozzle are assembled on the paper to form complete text or graphics. Since each character and graphic is different, the combination of nozzles and the number of nozzles used each time are not fixed.

The working principle of the thermal bubble jet printer is to provide a voltage pulse to the heater in each nozzle, so that the heater can generate heat rapidly. After the heating resistor in the nozzle is heated, a small air bubble will be generated inside the nozzle, which will squeeze out the ink at the outlet end of the nozzle and spray it on the paper, forming a circular ink dot on the paper. After the end of the voltage pulse, the heating resistor is also cooled down, so that the temperature in the nozzle drops rapidly, the air bubbles disappear, and the ink is refilled along the ink channel to the inside of the nozzle outlet.

See Figure 1. FIG. 1 shows the connection relationship between a voltage source 10 and each nozzle (such as 111 , 112 , 113 ) in an inkjet head 11 in the prior art. The voltage source 10 is used to provide voltage pulses to each nozzle. Each nozzle includes a heating resistor (such as 111A, 112A, 113A) and a switch (such as 111B, 112B, 113B).

Take nozzle 111 as an example. When the switch 111B is not turned on, there is no conduction between the heating resistor 111A and the ground. Therefore, no current flows through the heating resistor 111A, and there is no voltage drop across the heating resistor 111A. Assuming that in a certain operation of controlling the inkjet head 11, the nozzle 111 is set as the nozzle to be used, the switch 111B will be turned off, so that the heating resistor 111A forms a path with the ground terminal through the switch 111B. Then, the voltage source 10 supplies current to form a voltage drop across the heating resistor 111A. The ink in the nozzle 111 is pushed by the bubbles generated after being heated by the heating resistor 111A, that is, the ink is ejected from the ink outlet of the nozzle 111 to form ink droplets.

In practical applications, the switch in each nozzle may be as shown in Figure 2, which is composed of a sub-switch (such as 111C, 112C, 113C) and a metal oxide semiconductor (MOS) device (such as 111D, 112D, 113D) . When the sub-switch 111C is turned off, the gate (Gate) of the MOS component 111D is connected to the voltage source 10, so that the MOS component 111D enters the conduction state, whereby the heating resistor 111A can form a path with the ground terminal through the MOS component 111D .

The heating resistors, metal oxide semiconductor components in each inkjet head, and even the wiring and related connection lines connected between the voltage source 10 and each inkjet head will form a loading effect on the voltage source 10 . As known by those skilled in the art, the output impedance of an ideal voltage source is zero, so the ideal voltage source can provide a fixed voltage output regardless of the load value. However, in actual conditions, the impedances of various connection lines and the output impedance of the voltage source 10 cannot be zero; when connected to different loads, the voltage values provided by the voltage source 10 are slightly different.

As shown in Figure 1, if the nozzle 111 and the nozzle 112 are used at the same time, the heating resistor 111A and the heating resistor 112A are connected in parallel; compared with the case where only the nozzle 111 is used alone, the heating resistor 111A and the heating resistor 112A are connected in parallel to the voltage source The equivalent load formed by 10 is only half of the former (assuming that the resistance values of the heating resistor 111A and the heating resistor 112A are the same). Since each character and graphic is different, the number of nozzles used each time is not fixed. Each time the number of nozzles used is changed, the number of heating resistors that load the voltage source 10 is also different. Therefore, the voltage drop across the heating resistor formed by the voltage source 10 each time may be different due to the influence of the load value.

Most of the existing inkjet printers use a fixed driving voltage to provide the driving energy required by the inkjet head during printing. If the voltage source 10 provides a constant voltage value, affected by load impedance changes and various line impedances, the driving voltage obtained by each heating resistor will be insufficient or too large, so that the ink droplets in each nozzle cannot be ejected or The ink droplet is too large. The above phenomena will seriously affect the printing quality of the printer.

See Figure 3. Fig. 3 shows another prior art with two sets of voltage sources. The voltage source 20A is used for providing voltages to each heating resistor; the voltage source 20B is used for selectively providing voltages to the gates of each metal oxide semiconductor device. The main difference between FIG. 3 and FIG. 2 is that the voltage values required by each heating resistor and each metal oxide semiconductor component are different, so two sets of voltage sources are required to provide different voltage values. The prior art shown in FIG. 3 also suffers from the aforementioned voltage fluctuation problem.

Contents of the invention

In order to solve the above problems, the present invention provides an apparatus and method for providing nozzle voltage of an inkjet printer. According to the device and method of the present invention, the resolution of the user's printed manuscript and the impedance characteristics of each nozzle are taken into consideration. Therefore, the present invention can pre-compensate the voltage variation caused by the impedance of the nozzles and the impedance of various connecting lines according to the number of nozzles to be used, thereby providing stable and correct voltage values for each nozzle.

The apparatus and method according to the present invention are used in conjunction with an inkjet head included in an inkjet printer. The inkjet head includes a plurality of nozzles. The inkjet printer is capable of providing multiple print modes; each print mode corresponds to a respective number of nozzles.

The first preferred embodiment according to the present invention is a voltage supply device. The voltage supply device includes a look-up table, a selection module and an adjustable voltage supply. The look-up table is used for storing multiple sets of control signals corresponding to the multiple printing modes. The selection module is used for receiving an instruction; the instruction indicates that a user selects a printing mode from the printing modes as a final printing mode. The selection module selects a set of control signals corresponding to the final printing mode from the multiple sets of control signals stored in the look-up table as a set of final control signals according to the instruction. The adjustable voltage supplier is used for providing at least one voltage to the plurality of nozzles according to the set of final control signals.

A second preferred embodiment according to the present invention is a method of controlling an adjustable voltage supply. A look-up table is pre-provided and used to store multiple sets of control signals related to the printing mode. The method first receives an instruction; the instruction indicates that a user selects a printing mode from the printing modes as a final printing mode. According to the instruction, the method selects a set of control signals corresponding to the final printing mode from the multiple sets of control signals stored in the look-up table as a final control signal. The method then adjusts the adjustable voltage supply such that the adjustable voltage supply provides at least one voltage corresponding to the set of final control signals to the plurality of nozzles.

The advantages and spirit of the present invention can be further understood through the following detailed description of the present invention in conjunction with the accompanying drawings.

Description of drawings

Fig. 1 shows the connection relationship between the voltage source and each nozzle in the prior art.

FIG. 2 further shows a circuit diagram of the nozzle in FIG. 1 .

Fig. 3 shows the connection relationship between a voltage source and each nozzle in another prior art.

Fig. 4 shows a structural diagram of a voltage supply device according to a first preferred embodiment of the present invention.

Fig. 5 shows a structural diagram of a voltage supply device according to a second preferred embodiment of the present invention.

Fig. 6 shows a flowchart of a method according to a third preferred embodiment of the present invention.

Description of reference symbols

10: Voltage source 11: Inkjet head

111, 112, 113: nozzles 111A, 112A, 113A: heating resistors

111B, 112B, 113B: switches 111C, 112C, 113C: sub-switches

111D, 112D, 113D: MOS components

20A: first voltage source 20B: second voltage source

30: Voltage supply device 30A: Adjustable voltage supply

30B: Select Module 30C: Lookup Table

31: Command

40: Voltage supply device 40A: Adjustable voltage supply

40B: Select Module 40C: Lookup Table

41: Instructions 42: First line

43: Second cable S61～S63: Step process

Detailed ways

A main object of the present invention is to provide an apparatus and method for providing voltage to an inkjet head of an inkjet printer. The apparatus and method according to the present invention are used in conjunction with an inkjet head included in an inkjet printer. The inkjet head includes a plurality of nozzles. The inkjet printer is capable of providing multiple print modes; each print mode corresponds to a respective number of nozzles.

The first preferred embodiment according to the present invention is a voltage supply device. See Figure 4. Fig. 4 shows a structural diagram of a voltage supply device according to a first preferred embodiment of the present invention. The voltage supply device 30 includes an adjustable voltage supply 30A, a selection module 30B and a look-up table 30C. Similar to FIG. 2 , each inkjet head in FIG. 4 also includes a heating resistor, a metal oxide semiconductor device and a switch.

The present invention pre-calculates how much load all nozzles and line impedances will form on the voltage supply device 30 when the number of nozzles is different. Then, it is further calculated how much adjustment should be made inside the voltage supply device 30 in order to maintain an ideal voltage output value under various load values. The look-up table 30C is used to store multiple sets of control signals for controlling the voltage supply device 30 corresponding to various load values.

In practical applications, the adjustable voltage supply 30A is connected to the inkjet head through a row of wires. Common flat cables have a series impedance, which also causes voltage loss. In addition, because the voltage supply device 30 will be affected by the parasitic resistance and capacitance on the line when the voltage is transmitted to each inkjet head, the time when each inkjet head receives sufficient voltage (or current) will be slightly later than the voltage The time when the supply device 30 sends out voltage (or current). In order to timely supply the large current required by each inkjet head at the moment of turning on. According to the present invention, the look-up table 30C can also store information related to the response delay time of components on the line, so as to timely adjust the required voltage or current during printing in order to supplement the driving energy required by the inkjet head. That is to say, the plurality of control signals stored in the look-up table may also be related to the series impedance of the cable.

The selection module 30B is used for receiving an instruction 31; the instruction 31 indicates that a user selects a printing mode from the printing modes as a final printing mode. The selection module 30B selects a set of control signals from the multiple sets of control signals stored in the look-up table 30C according to the instruction 31 as a set of final control signals. In practical applications, the look-up table 30C and the selection module 30B can be integrated into a control unit. The adjustable voltage supplier 30A is used for providing at least one voltage value to the plurality of nozzles according to the set of final control signals.

Since the above-mentioned first preferred embodiment takes into consideration the resolution of the manuscript printed by the user and the impedance characteristic of the inkjet head. Therefore, the present invention can pre-compensate voltage changes caused by various impedances according to the number of nozzles to be driven, thereby providing stable and correct voltage values for each nozzle.

See Figure 5. Fig. 5 shows a structural diagram of a voltage supply device according to a second preferred embodiment of the present invention. The working principle of the voltage supply device 40 according to the second preferred embodiment of the present invention is the same as that of the voltage supply device 30 in FIG. 4 . In this embodiment, the voltage values required by each heating resistor and each MOS element are different, so the voltage supply device 40 provides a first voltage and a second voltage. The first voltage is provided to the heating resistors of each nozzle through the cable 42 ; the second voltage is provided to the switch of each nozzle through the cable 43 .

A third preferred embodiment of the present invention is a method of controlling an adjustable voltage supply. The adjustable voltage supply is used to match an inkjet head included in an inkjet printer. The inkjet head includes a plurality of nozzles. The inkjet printer is capable of providing multiple print modes; each print mode corresponds to a respective number of nozzles. A look-up table is pre-provided and used to store multiple sets of control signals related to the printing mode. See Figure 6. Fig. 6 shows a flowchart of a method according to a third preferred embodiment of the present invention. The method firstly receives an instruction in step S61, and the instruction indicates that a user selects a printing mode from the printing modes as a final printing mode. Step S62 selects a set of control signals corresponding to the final printing mode from the multiple sets of control signals stored in the look-up table as a final control signal according to the instruction. Step S63 then adjusts the adjustable voltage supply such that the adjustable voltage supply provides at least one voltage corresponding to the set of final control signals to the plurality of nozzles.

Through the above detailed description of the preferred embodiments, it is hoped that the characteristics and spirit of the present invention can be described more clearly, and the scope of the present invention is not limited by the preferred embodiments disclosed above. On the contrary, the intention is to cover various modifications and equivalent arrangements within the scope of the appended claims of the present invention.

Claims (9)

1. voltage supply device, this voltage supply device is contained in a ink gun in the ink-jet printer in order to cooperation, this ink gun comprises a plurality of nozzles, this inkjet printing function provides a plurality of printing models, corresponding to the quantity of other nozzle, this voltage supply device comprises each printing model separately:

One look-up table, this look-up table is in order to store the control signal of many groups corresponding to these a plurality of printing models;

One selects module, this selection module is in order to receive an instruction, this instruction expression one user is by selecting a printing model as a final printing model in the described printing model, this selects module and according to this instruction, is stored in control signal in this look-up table by these many groups and selects one group of control signal corresponding to this final printing model as one group of final control signal; And

One adjustable Voltage Supply Device, this adjustable Voltage Supply Device provides at least one voltage to these a plurality of nozzles in order to organize final control signal according to this.

2. voltage supply device as claimed in claim 1, wherein this look-up table and this selection are module integrated is a control module.

3. voltage supply device as claimed in claim 1, each nozzle wherein comprises a heating resistor and a switch, this heating resistor and this switch have an impedance respectively, and should many group control signals relevant with the impedance of the impedance of this heating resistor and this switch.

4. voltage supply device as claimed in claim 3, wherein this adjustable Voltage Supply Device is connected with this ink gun by a winding displacement, this winding displacement has a series connection impedance, and be stored in this look-up table should many group control signals also the series impedance with this winding displacement is relevant.

5. voltage supply device as claimed in claim 3, wherein comprise one first voltage and one second voltage at least one voltage that provides by this adjustable Voltage Supply Device, this first voltage offers the heating resistor of each nozzle, and this second voltage offers the switch of each nozzle.

One kind control one adjustable Voltage Supply Device method, this adjustable Voltage Supply Device is contained in a ink gun in the ink-jet printer in order to cooperation, this ink gun comprises a plurality of nozzles, this inkjet printing function provides a plurality of printing models, each printing model is separately corresponding to the quantity of other nozzle, one look-up table provides in advance and in order to store many groups control signal relevant with described printing model, this method comprises the following step:

Receive an instruction, this instruction expression one user is by selecting a printing model as a final printing model in the described printing model;

According to this instruction, be stored in control signal in this look-up table by these many groups and select one group of control signal corresponding to this final printing model as a final control signal; And

Adjust this adjustable Voltage Supply Device, make this adjustable Voltage Supply Device provide at least one correspondence in this voltage of organizing final control signal to these a plurality of nozzles.

7. method as claimed in claim 6, each nozzle wherein comprises a heating resistor and a switch, and this heating resistor and this switch have an impedance respectively, and should many group control signals relevant with the impedance of the impedance of this heating resistor and this switch.

8. method as claimed in claim 7, wherein this adjustable Voltage Supply Device is connected with this ink gun by a winding displacement, this winding displacement has a series connection impedance, be stored in this look-up table should many group control signals also the series impedance with this winding displacement is relevant.

9. method as claimed in claim 7 wherein comprises one first voltage and one second voltage at least one voltage that is provided by this adjustable Voltage Supply Device, and this first voltage offers the heating resistor of each nozzle, and this second voltage offers the switch of each nozzle.

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