KR100438707B1 - Apparatus and method for measuring ink level for ink jet printer - Google Patents

Abstract

An ink amount measuring apparatus and method for an ink jet printer are disclosed. In an ink jet printer, the apparatus for measuring the amount of ink contained in at least one cartridge mounted on a carriage senses a current flowing out of a pulse oscillation unit and a second electrode for applying an input pulse to the first electrode, and sensing A current sensing unit for outputting a result as an output signal, the first electrode and the second electrode being provided on opposite sides of the carriage in contact with the cartridge, the amount of ink being measured in accordance with the level of the output signal, and the cartridge The ink contained in corresponds to a dielectric, and the capacitance formed by the cartridge is variable according to the amount of ink when an input pulse is applied. Therefore, since the first and second electrodes are attached to the carriage, the cost of the cartridge can be lowered and the structural difficulty can be improved than the mounting of the electrodes on the consumable cartridge, thereby reducing the amount of ink at a lower level than the predetermined level. It can be detected continuously and has the effect of being able to eliminate the waste of ink in advance.

Description

Apparatus and method for measuring ink level for ink jet printer

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to ink jet printers, and more particularly, to an ink amount printer and method for an ink jet printer capable of measuring the amount of ink contained in a cartridge in an ink jet printer.

Generally, a carriage type ink jet printer has a small size cartridge (not shown) including an ink channel (not shown) and a nozzle (not shown). At this time, since the number of pages that one cartridge can print is limited, the ink amount has a relatively important meaning. For example, it is necessary to measure the amount of ink in order to prevent the ink from being exhausted while the page is not recognized by the user during the page, i.e., to recognize how much ink is left in the cartridge being used. As such, if the ink amount is recognized by the user, a warning message can be given to the user when the ink is almost consumed. Therefore, the user can not only take countermeasures but also replace the cartridge before printing a high resolution image requiring a large amount of ink, so that waste of ink or paper can be reduced in advance.

A conventional ink amount measuring apparatus is disclosed in US Patent No. US 5,682,184 entitled "System for sensing ink level and type of ink for an ink jet printer". The disclosed conventional ink level measuring device attaches the electrode plates 8A and 8B to both sides of the cartridge, applies an alternating current (AC) power supply 22 to the attached electrode plate 8A, and the other electrode plate 8B. The amount of ink is measured using the level of the output signal flowing out from the device. Here, as the amount of ink contained in the cartridge decreases, the capacitance formed by the cartridge decreases and the resistance increases. Therefore, the ink amount is detected from the change in capacitance.

However, the above-described conventional ink amount measuring apparatus mounts the electrode plates 8A and 8B on the cartridge, thereby raising the price of the ink cartridge which is a consumable, and placing the electrode plates 8A and 8B on the carrier card (not shown). ) And problems with making it difficult to connect to the main card (not shown).

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide an ink amount measuring apparatus for an ink jet printer capable of continuously detecting ink levels at a relatively low price by lowering the cost of cartridges and improving structural difficulties.

Another object of the present invention is to provide an ink amount measuring method for an ink jet printer performed by the ink amount measuring device.

1 is a block diagram of an ink amount measuring device for an ink jet printer according to the present invention.

2 is a view showing the appearance of a preferred embodiment according to the present invention of the carriage shown in FIG.

3 is a circuit diagram of a preferred embodiment of the present invention of the pulse oscillator shown in FIG.

FIG. 4 is a circuit diagram of preferred embodiments of the present invention according to the present invention.

5 is a graph showing the change according to the ink amount of the level of the digital form amplified result input from the ADC.

6 is a diagram illustrating an appearance of first and second electrodes and a cartridge.

FIG. 7 is a flowchart for explaining an ink amount measuring method according to the present invention performed in the apparatus shown in FIG. 1.

In order to achieve the above object, in an ink jet printer, an ink amount measuring device for an ink jet printer according to the present invention for measuring the amount of ink contained in at least one cartridge mounted on a carriage, applies an input pulse to the first electrode. And a current sensing unit configured to sense a current flowing out of the pulse oscillation unit and the second electrode, and output the sensed result as an output signal, wherein the first electrode and the second electrode face each other in contact with the carriage. The ink amount measured in response to the level of the output signal, respectively, is provided on the surfaces, and the ink contained in the cartridge corresponds to a dielectric material, and the ink is applied to the cartridge according to the amount of the ink when the input pulse is applied. The capacitance formed by this is preferably variable.

In order to achieve the above another object, the ink amount measuring method for an ink jet printer according to the present invention performed in the ink amount measuring device, the step of applying the input pulse to the first electrode, is discharged from the second electrode Sensing the current, amplifying the sensed result, converting the amplified result of the analog form into a digital form, and determining the amount of ink corresponding to the level of the amplified result of the digital form. It is preferable to have a step to.

Hereinafter, with reference to the accompanying drawings, the configuration and operation of the ink amount measurement apparatus for an ink jet printer according to the present invention will be described as follows.

1 is a block diagram of an ink amount measuring apparatus for an ink jet printer according to the present invention, which includes a pulse oscillation unit 10, a carriage 12, a current sensing unit 14, an amplifier 16, an analog / digital converter ( ADC (Analog to Digital Converter) 18 and the control unit 20.

In an ink jet printer, the carriage 12 shown in FIG. 1 has first and second electrodes 30 and 32 and at least one cartridge 34. That is, the ink amount measuring apparatus according to the present invention attaches the first and second electrodes 30 and 32 to the carriage 12 instead of the cartridge 34 unlike the conventional art. Here, the first and second electrodes 30 and 32 are provided on the opposite surfaces 40 and 42 of the carriage 12 to contact the cartridge 34 containing the ink 36.

FIG. 2 is a view showing the appearance of one preferred embodiment 12A according to the present invention of the carriage 12 shown in FIG. 1, with two first electrodes 52 and 54 and two second electrodes ( 50 and 56).

The carriage 12A shown in FIG. 2 can mount two cartridges, for example, one for color and one for black and white. Here, the first electrodes 52 and 54 are connected to each other, and the second electrodes 50 and 56 are not connected to each other. In this case, the first electrode 52 and the second electrode 50 face each other and contact one of the two cartridges, and the first electrode 54 and the second electrode 56 face each other and both Contact the other of the two cartridges.

Meanwhile, the pulse oscillator 10 shown in FIG. 1 applies an input pulse to the first electrode 30 or 52 and 54 of the carriage 12. At this time, the input pulse may be in the form of a square wave, it may have a frequency of several tens of kHz.

FIG. 3 is a circuit diagram of a preferred embodiment 10A of the pulse oscillator 10 shown in FIG. 1 according to the present invention, in which resistors R1, R2, R3, R4 and R5, first operational amplifier 60 are shown. And a first capacitor C1.

The resistor R1 of the pulse oscillator 10A shown in FIG. 3 is connected between the positive input terminal + of the first operational amplifier 60 and ground, which is a reference potential, and the resistor R2 is connected to the first operational amplifier. It is connected between the positive input terminal (+) of (60) and its output terminal, and the resistor (R3) is connected between the negative input terminal (-) of the first operational amplifier 60 and its output terminal. At this time, the first capacitor C1 is connected between the negative input terminal (−) of the first operational amplifier 60 and the ground which is the reference potential, and the resistors R4 and R5 are connected to the supply voltage Vdd and the first voltage. 1 are connected in parallel between the output terminals of the operational amplifier 60. The pulse oscillation unit 10A shown in FIG. 3 having the above-described configuration outputs an input waveform in the form of a square wave from the output terminal of the first operational amplifier 60 through the output terminal OUT2.

At this time, the current sensing unit 14 senses the current flowing out of the second electrode 32 or 50 and 56 of the carriage 12 and outputs the sensed result to the amplifier 16 as an output signal. . Here, since the ink 36 contained in the cartridge 34 corresponds to a dielectric, when the input pulse generated from the pulse oscillation unit 10 is applied to the carriage 12, the amount of ink 36 contained in the cartridge 34 is increased. As a result, the capacitance formed by the cartridge 34 is variable. As the capacitance varies, the amount of current flowing out of the second electrode 32 changes. If the input signal has a square wave shape, the output signal output from the current sensing unit 14 also has a square wave shape.

FIG. 4 is a circuit diagram of the preferred embodiments 14A and 16A of the current sensing unit 14 and the amplifying unit 16 shown in FIG. 1 according to the present invention, and the current sensing unit 14A constituted by the resistor R6. ) And amplification section 16A.

The current sensing unit 14A shown in FIG. 4 is composed of a resistor R6 that flows out through the second electrode 32 of the carriage 12 and is connected between a current input through the input terminal IN1 and a ground which is a reference potential. do. Here, the output signal output from the current sensing unit 14A corresponds to a voltage drop across the resistor R6. Therefore, as the capacitance changes, the current flowing through the resistor R6 changes, and as the current flowing through the resistor R6 changes, the level of the output signal changes.

As a result, the amount of ink remaining in the cartridge 34 can be measured corresponding to the level of the output signal output from the current sensing unit 14. To this end, the ink amount measuring apparatus shown in FIG. 1 includes an amplifier 16, an ADC 18, and a controller 20.

First, the amplifier 16 amplifies the output signal input from the current sensing unit 14, and outputs the amplified output signal to the ADC (18). To this end, the amplifier 16 may be implemented with resistors R7, R8 and R9, second and third capacitors C2 and C3 and a second operational amplifier 70, as shown in FIG. 4. Can be.

The resistor R7 of the amplifier 16A shown in FIG. 4 is connected between the negative input terminal (-) of the second operational amplifier 70 and ground, which is a reference potential, and the resistor R8 is connected to the second operational amplifier. It is connected between the negative input terminal (−) of 70 and its output terminal, and the resistor R9 is connected to the ADC 18 through the output terminal of the second operational amplifier 70 and the output terminal OUT3. At this time, the second capacitor C2 is connected between the negative input terminal (-) of the second operational amplifier 70 and the ground which is the reference potential, and the third capacitor C3 is connected to the ADC 18 and the reference potential. Connected between grounds. The amplifier 16A having the above-described configuration amplifies an output signal input from the current sensing unit 14 through the input terminal IN1, that is, a voltage falling on the resistor R6, and converts the amplified output signal to an output terminal OUT3. Output to the ADC (18).

The ADC 18 converts the analog amplified result input from the amplifying unit 16 into a digital form, and outputs the converted digital amplified result to the controller 20.

At this time, the controller 20 measures the amount of the ink 36 contained in the cartridge 34 from the level of the digital amplified result input from the ADC 18, and outputs the measured amount of the ink 36. Output via terminal OUT1. To this end, the control unit 20 stores a plurality of ink amounts, is addressed to a digital amplified result input from the ADC 18, and outputs a corresponding ink amount through the output terminal OUT1 (LUT: Look Up Table (22). For example, the lookup table 22 may store ink levels and levels of amplified results in digital form as shown in Table 1 below.

Ink amount (ml) Level of digitally amplified result (mV) 10 292 15 348 17 364 20 388 22 404 25 412 30 450 35 484 40 468 45 468 50 468

Fig. 5 is a graph showing the change according to the ink amount of the level of the digital form amplified result input from the ADC 18, where the vertical axis represents the level of the digital form amplified result, and the horizontal axis represents the ink amount, respectively.

The relationship between the ink amounts shown in Table 1 and the levels of the amplified results is as shown in FIG. As such, the controller 20 may determine the amount of the ink 36 contained in the cartridge 34 corresponding to the level of the digital amplified result input from the ADC 18.

FIG. 6 is a view showing the appearance of the first and second electrodes 30 and 32 and the cartridge 34.

The ink amount measuring apparatus according to the present invention shown in FIG. 1 may continuously detect the amount of the ink 36 in the predetermined range 80 shown in FIG. 6.

Meanwhile, according to the present invention, the ink amount output from the control unit 20 through the output terminal OUT1 may be visually displayed on a monitor (not shown) of the ink jet printer.

Hereinafter, a method of measuring an ink amount for an ink jet printer according to the present invention, which is performed in the ink amount measuring apparatus for an ink jet printer according to the present invention described above, will be described with reference to the accompanying drawings.

FIG. 7 is a flowchart illustrating an ink amount measuring method according to the present invention, which is performed in the apparatus shown in FIG. 1, by applying an input pulse to the carriage 12 to sense a current flowing out of the 12. (90th and 92nd steps) and determining the ink amount from the sensed results (94th through 98th steps).

In the ink amount measuring method according to the present invention performed in the ink amount measuring apparatus shown in FIG. 1, the pulse oscillation unit 10 applies the above-described input pulse to the first electrode 30 of the carriage 12 (90) step). After operation 90, the current sensing unit 14 senses the current flowing out of the second electrode 32 of the carriage 12 (operation 92).

After step 92, the amount of ink is measured using the sensed result, that is, the sensed current (steps 94 to 98).

In detail, after step 92, the amplifier 16 amplifies the results sensed by the current sensing unit 14 (step 94). After the 94 th step, the ADC 18 converts the amplified result of the analog form inputted from the amplifier 16 into a digital form (step 96). After step 96, the controller 20 determines the ink amount corresponding to the level of the digital amplified result input from the ADC 18 (step 98).

As described above, the ink amount measuring apparatus and method for an ink jet printer according to the present invention are consumable because the first and second electrodes 30 and 32 are attached to the carriage 12 rather than the cartridge 34. It is possible to lower the cost of the cartridge than to mount the electrodes on the in-cartridge 34 and to improve the structural difficulty, thereby to continuously detect the amount of ink at a lower level than the predetermined level at a relatively low price, and to reduce the waste of ink. It has the effect of being able to remove it in advance.

Claims (6)

An ink jet printer, comprising: an ink amount measuring device for measuring an amount of ink contained in at least one cartridge mounted on a carriage, A pulse oscillator for applying an input pulse to the first electrode; And A current sensing unit configured to sense a current flowing out of the second electrode and output the sensed result as an output signal, The first electrode and the second electrode are respectively provided on opposite surfaces of the carriage in contact with the cartridge, the amount of the ink is measured according to the level of the output signal, the ink contained in the cartridge is a dielectric And a capacitance formed by the cartridge according to the amount of the ink when the input pulse is applied to the ink amount measuring device for an ink jet printer. The method of claim 1, wherein the current sensing unit A resistor connected between said current and reference potential, And the output signal corresponds to a voltage applied to both ends of the resistor. The ink amount measuring apparatus of claim 1, wherein An amplifier for amplifying the output signal; An analog / digital converter for converting the amplified result of the analog form inputted from the amplifier into a digital form; And And a control unit for measuring the ink amount from the level of the amplified result in the digital form. The method of claim 3, wherein the control unit An ink amount measuring apparatus for an ink jet printer, characterized in that for storing a plurality of ink amounts and addressing the amplified result of the digital form and outputting the corresponding ink amounts. An ink amount measuring method performed by the ink amount measuring apparatus of claim 1, (a) applying the input pulse to the first electrode; (b) sensing the current flowing out of the second electrode; (c) amplifying the sensed results; (d) converting the amplified result of the analog form into a digital form; And (e) determining the ink amount corresponding to the level of the amplified result of the digital form. delete