JPH10119301A - Ink residue detector - Google Patents

Abstract

PROBLEM TO BE SOLVED: To capture a detection signal as it is without using an A/D converter and to digitalize it by outputting ink residue as a pulse width of a signal by utilizing a multivibrator circuit having a resistor whose resistance value changes in respnose to the ink residue. SOLUTION: A residue detector circuit 50 constitutes a multivibrator circuit by a resistor equivalently indicating an electric resistance of an ink cartridge 7, timing capacitor 52, and a logic IC 51. First and second electrodes 60, 61 are assembled in the cartridge 7. An electric resistance between a pair of the electrodes of the first and second electrodes is changed according to the ink residue. The circuit 50 outputs a detection signal β of a pulse-like waveform at an input signal α as a starting point in response to the change of the resistance. The IC 51 has a resistor and a capacitor connected to Rx/Cx terminal and a Cx terminal to continue a predetermined time monostable mode decided by the resistor and capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the remaining amount of ink in an ink tank, and more particularly to a device for detecting the remaining amount of ink electrically.

[0002]

2. Description of the Related Art Conventionally, a printing apparatus such as an ink jet printer holds ink in an ink tank,
The print recording is performed by the print head ejecting the ink supplied from the ink tank to the print-receiving medium. If the ink in the ink tank runs out, printing cannot be performed. Therefore, it is necessary to replace the ink tank with a new ink tank and replenish the ink before the ink runs out. Therefore, a device for detecting the amount of ink in the ink tank is indispensable.

Therefore, conventionally, an ink remaining amount detecting device for detecting the remaining amount of ink at any time is provided in an ink tank fixed to the main body of the ink jet printer. In order to detect the remaining amount of the ink, for example, a method of detecting a floating of a built-in magnet that moves in accordance with a change in the ink level with a reed switch, a method of confirming the ink level with an optical sensor, and the like have been adopted. Was. However, such a device for detecting the remaining amount of ink requires complicated components, and the device itself is liable to malfunction. There were inconveniences such as detection failure.

In order to solve such problems and disadvantages, there has been proposed an ink remaining amount detecting device using a detecting circuit composed of two electrodes arranged in the ink tank with a difference in height. In this method, the resistance value between two electrodes is detected, and the remaining amount of ink is estimated based on the resistance value. Generally, the ink is not a good conductor or an insulator but a conductor having a certain resistance to electricity. Therefore, the electric resistance between the electrodes changes depending on the amount of ink interposed between the two electrodes. Therefore, it is possible to detect the amount of ink by supplying a signal to the detection circuit and measuring a resistance change between the electrodes.

[0005]

However, the conventional ink remaining amount detecting device of the type in which an electrode is provided in the ink tank has the advantage that highly reliable detection is possible, but the resistance value is low. There is a problem that a control unit for judging a change becomes complicated.

The detection signal output from the detection circuit of the conventional ink remaining amount detection device is an analog signal that outputs a change in the resistance value between the electrodes as a change in the voltage value. The signal could not be processed directly. Therefore, it is necessary to add an A / D converter for converting an analog signal to a digital signal or the like to the control circuit, and accompanying this, the interface or the like has to be complicated. As a result, there is a problem that the ink remaining amount detecting device becomes complicated and large as a whole, resulting in an increase in cost.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned conventional problems. A signal relating to the remaining amount of ink output from a detection circuit is converted into a logic signal which can be digitally processed. A simple and compact ink remaining amount that can be output to a control device and does not require an A / D converter that converts the ink remaining amount data from an analog signal to a digital signal. It is an object to provide a detection device.

[0008]

According to a first aspect of the present invention, there is provided an ink remaining amount detecting device which is attached to a printing device and supplies ink to a print head. Pulse generating means disposed in the ink tank and having a multivibrator circuit composed of a resistor having a resistance value that changes according to the remaining amount of ink present in the ink tank; and , A signal for performing a detection operation to the pulse generating means, a pulse output from the pulse generating means in response to the input signal, and the remaining amount of ink is determined based on the pulse of the pulse. Detecting means for determining.

In the ink remaining amount detecting device according to the first aspect of the invention, a multivibrator circuit having a resistor whose resistance value changes according to the ink remaining amount is used, and the ink remaining amount is determined not by a voltage level change but by a pulse width. And output it. Therefore,
The detection means can take in the detection signal as it is without using an A / D converter or the like, and directly perform digital processing. This greatly simplifies the configuration of the ink remaining amount detecting device, and can realize great advantages in terms of cost and size.

According to a second aspect of the present invention, there is provided the ink remaining amount detecting device according to the first aspect, wherein the pulse generating means is disposed in the ink tank, and the pulse generating means is provided in the ink tank. , A pair of electrodes forming the resistor, a capacitor and a logic IC
Consists of

In the ink remaining amount detecting device according to the second aspect, the circuit configuration can be made compact, and the apparatus can be implemented without particularly changing the control circuit of the ink jet printer. Further, in the above configuration, since a high-performance element or circuit mechanism is not used, it can be incorporated in a control device of an ink jet printer.

According to a third aspect of the present invention, there is provided an ink remaining amount detecting device attached to a printing device for detecting the remaining amount of ink in an ink tank for supplying ink to a print head. Pulse generating means having a multivibrator circuit which is provided in the ink tank and includes a capacitor having a capacitance which varies according to the remaining amount of ink present in the ink tank; and A signal for performing a detecting operation is given to the means, and a pulse output from the pulse generating means is received in response to the input signal, and the remaining amount of ink is determined based on the pulse width of the pulse. Means.

According to a third aspect of the present invention, a multi-vibrator circuit having a capacitor whose capacitance changes according to the remaining amount of ink is used. And output it. Therefore, the detection means does not use an A / D converter or the like,
The detection signal can be taken as it is, and digital processing can be directly performed. This greatly simplifies the configuration of the ink remaining amount detecting device, and can realize great advantages in terms of cost and size.

According to a fourth aspect of the present invention, there is provided the ink remaining amount detecting device according to the third aspect, wherein the pulse generating means is disposed in the ink tank and the ink existing in the ink tank is provided. , A pair of electrodes constituting the capacitor, a resistor and a logic IC
Consists of

In the ink remaining amount detecting device according to the fourth aspect, the circuit configuration can be made compact, and it can be implemented without particularly changing the control circuit of the ink jet printer. Further, in the above configuration, since a high-performance element or circuit mechanism is not used, it can be incorporated in a control device of an ink jet printer.

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an ink remaining amount detecting device according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic perspective view showing the internal configuration of an ink jet printer provided with an ink remaining amount detecting device according to the present invention. The inkjet printer 1 has a cylindrical platen roller 4 rotatably supported on a frame 3 by a rotating shaft 2 extending in the left-right direction. The platen roller 4 conveys the printing paper P as a recording medium supplied from a paper feeding cassette or a manual paper feeding unit while facing the recording head 5, and constitutes a part of a paper feeding device. The recording head 5 is removably mounted on a carriage 8 together with a head unit 6 and ink cartridges 7a to 7d for supplying inks of four colors (cyan, yellow, magenta, and black) to the recording head 5.

The carriage 8 has its front portion supported by a carriage shaft 8a provided in parallel with the axis of the platen roller 4, whereby the recording head 5 mounted on the carriage 8 is supported by the platen roller 4. The recording operation is performed while sliding in a direction crossing the printing paper P. A carriage motor 10 for driving the carriage 8 drives the carriage 8 by a belt 11 and pulleys 12 and 13.

A barge device 15 is provided on the left side of the platen roller 4 in FIG. 1, that is, outside the recording range for the printing paper P, to recover non-ejection or ejection failure of the recording head 5. The purging device 15 is provided with a suction cap 16 which covers the nozzles of the recording head 5 and sucks defective ink inside the recording head 5 by a negative pressure generated by the pump to remove the recording head 5. It is to recover. The purge device 15 uses a line feed (LF) motor 43 (FIG. 3) as a driving source,
The drive source is shared with the platen roller 4. The driving force of the line feed motor is configured to be transmitted to the purge device 15 via the pump cam gear 17 when the carriage 8 enters the recovery area.

FIG. 2 is a partially cutaway rear perspective view of a head unit 6 having a recording head 5 according to an embodiment of the present invention. The recording head 5 in the head unit 6
Head chips (not shown) each having a nozzle capable of independently ejecting color ink are provided in a row.
Each head chip includes a substrate having a piezoelectric ceramic element that generates energy for ink ejection, and the substrate is deformed by controlling the power supply to the element, so that the volume of a channel, which is an ink flow path, changes. Ink of each color supplied from 7a to 7d is ejected from each nozzle.

The head unit 6 includes a holder 21 and a cap 22 as inserts, and a plurality of head chips, which are the main components of the recording head 5, are arranged on the entire surface of the holder 21, and penetrate the entire wall. An ink introduction section 23 of the head chip is provided. A filter 24 for removing foreign matter and the like is attached to the ink supply channel open end of the ink introduction unit 23. The holder 2 has a rib 2
When the four color ink cartridges 7a to 7d are set in the spaces partitioned by 5, the ink supply ports are joined to the ink introduction unit 23, and the ink is supplied to the head chip.

Next, the configuration of the control system of the printer 1 will be described with reference to FIG. FIG. 3 is a block diagram showing a control system of the printer 1. The printer 1 includes a CPU 31 (detection means) for controlling each part of the printer 1 and a gate array 34 (hereinafter referred to as G / A) which receives print data from a host computer 32 via an interface 33 and controls development of the print data. Circuit). Between the CPU 31 and the G / A circuit 34, a ROM 35 in which a work program and the like are recorded, and a G / A circuit 3
4 is provided with a RAM 36 for temporarily storing the print data received from the host computer 32, and receives necessary data therefrom.

The CPU 31 has a paper sensor 37 for detecting the presence or absence of print paper, an origin sensor 38 for detecting that the print head 5 is at the home position, and a residual sensor for detecting the remaining amount of ink in the ink cartridge 7. The quantity detection circuit 50 is connected. Note that the remaining amount detection circuit 50 corresponds to the pulse generation means of the present invention. CPU3
1 functions as detecting means for detecting the remaining amount of ink in the ink cartridge 7 based on the remaining amount detection circuit 50. The remaining amount detection circuit 50 will be described later in detail.

The CPU 31 includes a first motor driver 41 for driving the carriage motor 10, a second motor driver 42 for driving the line feed motor 43, and an operation panel 43 for supplying various signals to the CPU 31.
Etc. are connected. The G / A circuit 34 is connected to an image memory 45 for temporarily storing print data received from the host computer 32 as image data. The print head driver 46 includes the G / A circuit 3
4, print data 46a, transfer clock 46
b, and operates based on the print lock 46c to drive the print head 5. The G / A circuit 34 is also connected to an encoder sensor 47 that measures a moving speed of the carriage 8 and determines a print timing.

Next, the configuration and operation of the remaining amount detection circuit 50 will be described with reference to FIGS. FIG. 4 is a circuit diagram showing a circuit configuration of the remaining amount detection circuit, and FIG. 5 is a time chart of input / output of the remaining amount detection circuit 50. In FIG. The signal β is a pulse having a pulse width determined by the resistance value (R) of the resistor having a resistance value that changes according to the remaining amount of ink present in the ink cartridge and the capacitance (C) of the timing capacitor 52. , Detection signals input to the CPU 31.

The remaining amount detection circuit 50 comprises a multivibrator circuit comprising a resistor which equivalently indicates the electric resistance of the ink cartridge 7, a timing capacitor 52, and a logic IC 51. A first electrode 60 and a second electrode 61 are incorporated in the ink cartridge 7, and the electric resistance between the pair of electrodes including the first electrode and the second electrode changes depending on the remaining amount of ink. In response to the change in the electric resistance, the remaining amount detection circuit 50 outputs a detection signal β having a pulse-like waveform starting from the input signal α.

The logic IC 51 has a function of connecting a resistor and a capacitor to the Rx / Cx terminal and the Cx terminal, thereby continuing the monostable mode for a predetermined time determined by the resistor and the capacitor. Such a logic IC
Is well known, and a detailed description thereof will be omitted here.

Next, the operation of the remaining amount detecting circuit 50 configured as described above will be described with reference to FIG. When the measurement signal α that is a square wave is input to the remaining amount detection circuit 50, (ta1, tb)
1) The logic IC 51 outputs a detection signal β having a waveform determined by the resistance value (R) of the resistor formed between the pair of electrodes and the capacitance (C) of the timing capacitor 52. For example, when the ink remains sufficiently in the ink cartridge 7 and the resistance value of the resistor is small, the pulse width of the detection signal β output from the logic IC 51 is set to be equal to the resistance value (R1) of the resistor. Capacitor 5
It is determined by the capacitance (C) of No. 2 and becomes Ta (see FIG. 5A: waveform β).

On the other hand, if the amount of ink remaining in the ink cartridge 7 decreases and the resistance value of the resistor increases, the detection signal β output from the logic IC 51
Is determined by the resistance value (R2) of the resistor and the capacitance (C) of the timing capacitor 52, and becomes Tb (see B in FIG. 5: waveform β). Here, since the resistance value (R2) of the resistor is larger than the resistance value (R1) of the resistor, the pulse width Tb is wider than the pulse width Ta.

As described above, the pulse width of the detection signal β output from the logic IC 51 depends on the change in the resistance value (R) of the resistor, that is, the resistance value (R) of the resistor according to the remaining amount of ink. And the capacitance of the timing capacitor 52 (C). At this time, the pulse width T is determined by T = CR. Therefore, since the detection signal β can be a logic signal, the A / D converter required for the conventional remaining ink amount detection device can be eliminated, and the configuration of the interface can be simplified. Can be

Subsequently, a detection signal β for detecting the remaining amount of ink.
The determination of the presence or absence of the ink performed by the CPU 31 based on the above will be described with reference to FIG. FIG. 6 is a flowchart showing the flow of the ink remaining amount detection program. CPU3
1 first clears the pulse width measurement counter (S
1). Next, a measurement signal α that is a pulse signal is generated (S2) (see FIG. 5A: waveform α: ta1), and a rising edge of the detection signal β is waited for (S3: NO). Here, when the rising edge of the detection signal β is detected (S3: YES), the pulse width measurement counter is incremented (S4), and the control waits for the falling edge of the detection signal β (S4).
5: NO). Here, when the falling edge of the detection signal β is detected (S5: YES), the current value of the pulse width measurement counter is compared with a prescribed value set in the ROM 35 in advance (S6). Here, for example,
The specified value is set to 10,000. When the count number counted in S4 is not equal to or more than the specified value (S6: N
In O), the program is terminated as it is. If the counted number is equal to or more than the specified value (S6: YES), an ink-out process such as an instruction to the effect that "ink in ink cartridge 7 has run out" is performed on switch panel 43 in S7.

The contents of each of the above-described processes will be specifically described with reference to FIG. First, the operation of the CPU 31 when there is ink will be described. In FIG. 5A, the measurement signal α is input (ta1), and the detection signal β rises from the fall, and the resistance value (R1)
After the monostable operation for a predetermined time determined by the capacitance (C), the detection signal β falls (ta2). The pulse width of the detection signal β is Ta. At this time, if Ta is 4 milliseconds and the time required for the processing in steps S4 and S5 is 1 microsecond, the value of the pulse width measurement counter is It will be 4000. Therefore, since the value of the pulse width measurement counter is smaller than the specified value (10000), the determination in S7 is NO, and the ink remaining amount in the ink cartridge 7 is sufficient.

On the other hand, the operation of the CPU 31 when there is no ink, that is, in FIG.
The measurement signal α is input (tb1), and the detection signal β rises from the fall as a starting point. After the monostable operation for a predetermined time determined by the resistance value (R2) and the capacitance (C), the detection signal β rises. (Tb2). The pulse width of the detection signal β is Tb. At this time, if Tb is 14 milliseconds and the time required for the processing in steps S4 and S5 is 1 microsecond, the value of the pulse width measurement counter becomes 14,000. Therefore, the value of the pulse width measurement counter is equal to or greater than the specified value (10000).
The determination in S7 is YES, and it is time to replace the ink cartridge 7 with a new ink cartridge 7 because the remaining amount of ink in the ink cartridge 7 has decreased. Therefore, the user is notified on the switch panel 43 by instructing that "the ink in the ink cartridge 7 has run out".

In the ink remaining amount detecting device according to the first embodiment described in detail above, a multivibrator circuit constituted by a resistor, a capacitor, and a logic IC whose resistance value changes according to the ink remaining amount is provided. A detection signal β having a different pulse width is obtained in accordance with the remaining amount of ink, and the pulse width of the detection signal β is measured by a timer based on the detection signal β from the multivibrator circuit, thereby detecting the remaining amount of ink. Is done. Therefore, digital processing in which a logic signal is taken in can be performed without using an A / D converter or the like. This greatly simplifies the configuration of the ink remaining amount detection device, and can realize significant advantages in terms of cost and size.

Further, the multivibrator circuit in the remaining amount detection circuit 50 includes a pair of electrodes 60 and 61 disposed in the ink cartridge 7 and a timing capacitor 5.
2 and a logic IC 51, and this circuit configuration can be made compact and can be implemented without particularly changing the control circuit of the ink jet printer. Further, it is also possible to incorporate the device into a control circuit of an inkjet printer without using a high-performance element or circuit configuration.

Next, a description will be given of an ink remaining amount detecting device according to a second embodiment with reference to FIGS. FIG. 7 is a circuit diagram showing a circuit configuration of the remaining amount detection circuit 50, and FIG. 8 is a time chart of input / output of the remaining amount detection circuit 50. The signal, the measurement signal α, and the detection signal β in FIG.
Is the same as in the first embodiment. Here, the ink remaining amount detecting device according to the second embodiment has basically the same configuration as the ink remaining amount detecting device of the first embodiment, and the ink remaining amount is stored in the ink cartridge. A pair of electrodes constituting a capacitor whose capacitance changes according to the amount is provided, a resistor having a predetermined resistance value is provided, and a logic circuit and a logic IC constitute a multi-vibration circuit. Unlike the first embodiment, the remaining configuration has the same configuration. Therefore, in the following description, the same elements and the like as in the first embodiment will be described with the same reference numerals.

The remaining amount detection circuit 50 comprises a multivibrator circuit composed of a capacitor equivalently representing the capacitance of the ink cartridge 7, a timing resistor 53 and a logic IC 51. A first electrode 62 and a second electrode 63 are incorporated in the ink cartridge 7, and the capacitance between the pair of electrodes including the first electrode and the second electrode changes depending on the remaining amount of ink. In response to this change in capacitance, the remaining amount detection circuit 50 outputs a detection signal β having a pulse-like waveform starting from the input signal α.

Next, the operation of the remaining amount detection circuit 50 configured as described above will be described with reference to FIG. When the measurement signal α, which is a square wave, is input to the remaining amount detection circuit 50, (tc1, td
1) The logic IC 51 outputs a detection signal β having a waveform determined by the capacitance (C) of the capacitor formed between the pair of electrodes and the resistance value (R) of the timing resistor 53. For example, if there is sufficient ink remaining in the ink cartridge 7 and the capacitance of the capacitor is large,
The pulse width of the detection signal β output from the logic IC 51 is determined by the capacitance (C1) of the capacitor and the timing resistance 5
8 is determined by the resistance value (R) of FIG.
C: see waveform β).

On the other hand, when the amount of ink remaining in the ink cartridge 7 decreases and the capacitance of the capacitor decreases, the pulse width of the detection signal β output from the logic IC 51 changes to the capacitance of the capacitor. Capacity (C2)
And Td, which is determined by the resistance value (R) of the timing resistor 53 (see D in FIG. 8: waveform β). Here, since the capacitance (C2) of the capacitor is smaller than the capacitance (C1) of the capacitor, the pulse width Td is smaller than the pulse width Tc.

As described above, the pulse width of the detection signal β output from the logic IC 51 depends on the change in the capacitance (C) of the capacitor, that is, the capacitance (C) of the capacitor according to the remaining amount of ink. And the resistance value (R) of the timing resistor 53. At this time, the pulse width T is determined by T = CR. Therefore, since the detection signal β can be a logic signal, the A / D converter required for the conventional remaining ink amount detection device can be eliminated, and the configuration of the interface can be simplified. Can be

Subsequently, the detection signal β for detecting the remaining amount of ink.
The determination of the presence or absence of ink performed by the CPU 31 based on the above will be described with reference to FIG. FIG. 9 is a flowchart showing the flow of the remaining ink amount detection program. CPU3
1 first clears the pulse width measurement counter (S1
1). Next, a measurement signal α which is a pulse-like signal is generated (S12) (see FIG. 8A: waveform α: tc1), and a rising edge of the detection signal β is waited for (S13: NO). Here, when the rising edge of the detection signal β is detected (S13: YES), the pulse width measurement counter is incremented (S14), and the control waits for the falling edge of the detection signal β (S15: NO). Here, when the falling edge of the detection signal β is detected (S15: YES), the current value of the pulse width measurement counter is compared with a prescribed value set in the ROM 35 in advance (S16). Here, for example, the specified value is set to 10000. S
When the count number counted in 14 is equal to or more than the specified value (S16: YES), the program is terminated as it is. If the count is not equal to or greater than the specified value (S
16: NO), an ink-out process such as an instruction to the effect that "the ink in the ink cartridge 7 has run out" is performed on the switch panel 43 in S17.

The contents of each process described above will be specifically described with reference to FIG. First, the operation of the CPU 31 when there is ink will be described. In FIG. 8A, a measurement signal α is input (tc1), a detection signal β rises from the fall, and after a monostable operation for a predetermined time determined by the resistance value (R) and the capacitance (C1), The detection signal β falls (tc2). The pulse width of the detection signal β is Tc.
If it is milliseconds and the time required for the processing in steps S14 and S15 is 1 microsecond, the value of the pulse width measurement counter becomes 16000. Therefore, since the value of the pulse width measurement counter is larger than the specified value (10000), S
The determination at 17 is YES, and the remaining amount of ink in the ink cartridge 7 is sufficient.

On the other hand, the operation of the CPU 31 when there is no ink, that is, in FIG.
The measurement signal α is input (td1), the detection signal β rises from the fall, and after the monostable operation for a predetermined time determined by the resistance value (R) and the capacitance (C2), the detection signal β rises. Go down (td2). The pulse width of the detection signal β is Td. At this time, Td is 6 milliseconds, and the time required for the processing in steps S14 and S15 is 1
In the case of microseconds, the value of the pulse width measurement counter becomes 6000. Therefore, the value of the pulse width measurement counter is equal to or less than the specified value (10000).
The determination in S17 is NO, and it is time to replace the ink cartridge 7 with a new ink cartridge 7 because the remaining amount of ink in the ink cartridge 7 has decreased. Therefore, the user is notified on the switch panel 43 by instructing that "the ink in the ink cartridge 7 has run out".

In the ink remaining amount detecting device according to the second embodiment described in detail above, a multivibrator circuit composed of a capacitor, a resistor, and a logic IC whose capacitance changes according to the ink remaining amount is provided. A detection signal β having a different pulse width is obtained according to the remaining amount of ink, and the pulse width of the detection signal β is measured by a timer based on the detection signal β from the multivibrator circuit, so that the remaining amount of ink is obtained. Is detected. Therefore, digital processing in which a logic signal is taken in can be performed without using an A / D converter or the like. This greatly simplifies the configuration of the ink remaining amount detection device, and can realize significant advantages in terms of cost and size.

Further, the multivibrator circuit in the remaining amount detecting circuit 50 includes a pair of electrodes 62 and 63 disposed in the ink cartridge 7, a timing resistor 53, and a logic IC 51. Can be made compact and can be implemented without particularly changing the control circuit of the ink jet printer. Further, it is also possible to incorporate the device into a control circuit of an inkjet printer without using a high-performance element or circuit configuration.

It should be noted that the present invention is not limited to the above embodiment, and various changes can be made without departing from the spirit of the present invention.

For example, the resistor shown in the above embodiment,
Not only a circuit forming a multivibrator circuit by a capacitor and a logic IC, but also any circuit forming a monostable multivibrator can be used.

Although the embodiment has been described with respect to the detection of the remaining amount of ink, the liquid to be detected is not limited to ink, and any liquid that can detect the remaining amount can be used. is there.

Further, in the embodiment, the example in which the presence or absence of the ink is determined has been described. However, the remaining amount of the ink may be evaluated in multiple stages according to the pulse width.

[0049]

As described above, the ink remaining amount detecting apparatus according to the first aspect utilizes a multivibrator circuit having a resistor whose resistance value changes according to the ink remaining amount, and determines the remaining ink amount as a voltage. The signal is output in the form of the pulse width of the signal instead of the level change. Therefore, without using an A / D converter or the like, digital processing can be performed by directly taking in the detection signal. This greatly simplifies the configuration of the ink remaining amount detecting device, and can realize great advantages in terms of cost and size.

According to a second aspect of the present invention, there is provided the ink remaining amount detecting device according to the first aspect, wherein the pulse generating means is provided in the ink cartridge, and the ink existing in the ink cartridge is provided. And a capacitor and a logic IC. The circuit configuration can be made compact, and the control circuit of the ink jet printer can be implemented without particular change. It is possible to do. Further, in the above configuration, since a high-performance element or circuit mechanism is not used, it can be incorporated in a control device of an ink jet printer.

Further, the ink remaining amount detecting device according to the third aspect uses a multivibrator circuit having a capacitor whose capacitance changes according to the ink remaining amount, and determines the ink remaining amount by changing the voltage level. Instead, it is output in the form of a signal pulse width. Therefore, without using an A / D converter or the like, digital processing can be performed by directly taking in the detection signal. This greatly simplifies the configuration of the ink remaining amount detecting device, and can realize great advantages in terms of cost and size.

According to a fourth aspect of the present invention, there is provided the ink remaining amount detecting device according to the third aspect, wherein the pulse generating means is disposed in the ink cartridge, and the pulse generating means is provided in the ink cartridge. And a resistor and a logic IC. The circuit configuration can be made compact, and the control circuit of the ink jet printer can be implemented without particular change. It is possible to do. Further, in the above configuration, since a high-performance element or circuit mechanism is not used, it can be incorporated in a control device of an ink jet printer.

[Brief description of the drawings]

FIG. 1 is a perspective view showing the appearance of a printing apparatus provided with an ink remaining amount detecting device according to the present invention.

FIG. 2 is a perspective view of a head unit of a printing apparatus provided with an ink remaining amount detecting device according to the present invention.

FIG. 3 is a block diagram of a printing apparatus provided with an ink remaining amount detecting device according to the present invention.

FIG. 4 is a circuit diagram showing an internal configuration of an ink remaining amount detecting device according to the first embodiment of the present invention.

FIG. 5 is a time chart illustrating potentials (signals) at respective points of a circuit constituting the remaining ink amount detection device according to the first embodiment of the present invention.

FIG. 6 is a flowchart illustrating a flow of a process for detecting the presence or absence of ink according to the first embodiment of the present invention.

FIG. 7 is a circuit diagram showing an internal configuration of an ink remaining amount detecting device according to a second embodiment of the present invention.

FIG. 8 is a time chart showing potentials (signals) at respective points of a circuit constituting a remaining ink amount detecting device according to a second embodiment of the present invention.

FIG. 9 is a time chart showing potentials (signals) at respective points when there is no ink in a circuit constituting the remaining ink amount detecting device according to the second embodiment of the present invention.

[Explanation of symbols]

 7 Ink cartridge 50 Remaining amount detection circuit 51 Logic IC 52 Capacitor 53 Resistance 60 First electrode 61 Second electrode 62 First electrode 63 Second electrode

Claims (4)

[Claims] 1. An ink remaining amount detecting device attached to a printing device for detecting the remaining amount of ink in an ink cartridge for supplying ink to a print head, wherein the remaining amount of ink is provided in the ink tank. A pulse generating means having a multivibrator circuit composed of a resistor having a resistance value that varies according to the amount of remaining ink present, and receiving an input signal and outputting a pulse having a pulse width corresponding to the amount of remaining ink; and An input signal for performing a detecting operation is provided to the pulse generating means, a pulse output from the pulse generating means is received in response to the input signal, and the remaining amount of ink is determined based on the pulse width of the pulse. An ink remaining amount detecting device, comprising: detecting means for determining an amount. 2. The pulse generating means is provided in the ink tank, and includes a pair of electrodes constituting the resistor in cooperation with ink present in the ink tank, a capacitor, and a logic IC. The ink remaining amount detecting device according to claim 1, wherein: 3. An ink remaining amount detecting device attached to a printing device for detecting the remaining amount of ink in an ink tank for supplying ink to a print head, wherein the ink remaining amount detecting device is disposed in the ink tank. Having a multivibrator circuit composed of a capacitor having a capacitance that varies according to the amount of remaining ink present in the
A pulse generation unit that receives an input signal and outputs a pulse having a pulse width corresponding to the amount of remaining ink, and provides an input signal for performing a detection operation to the pulse generation unit, and responds to the input signal. A detection unit that receives a pulse output from the pulse generation unit and determines the remaining amount of ink based on the pulse width of the pulse. 4. The pulse generating means is provided in the ink tank, and comprises a pair of electrodes constituting the capacitor in cooperation with ink present in the ink tank, a resistor, and a logic IC. The ink remaining amount detecting device according to claim 3, wherein: