JPH058407A - Ink jet printer - Google Patents

Abstract

PURPOSE:To detect a residual quantity of ink only with an ink discharging electrode without providing an electrode for exclusive use on detection of the residual quantity of ink to an ink discharge part. CONSTITUTION:A pair of electrodes 4, 5 for discharge on ink are provided inside a nozzle 7 connected to an ink tank 2 housing conductive ink 1. AC pulse voltage is impressed to the electrode with an AC pulse voltage generator 12. The conductive ink 1 expanded by heating by an electrifying current 6 is discharged from a discharge opening 3 to print a dot. After impressing a pulse line for discahrge of one dot printing, the AC pulse generator 12 impresses DC or AC pulse voltage for detection of an ink residual quantity. An ink residual quantity-detector 10 detects an electrifying current quantity by said ink residual quantity detecting pulse and when it is a specific current quantity or lower, judges that the ink has been consumed. A pair of the electrodes 4 and 5 serve both as ink discharging use and ink residual quantity detecting use.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink remaining amount detecting means in an ink jet printer used for print output of an office computer or a personal computer.

[0002]

2. Description of the Related Art In recent years, printers have become widespread, but in an ink jet printer, a means for knowing the remaining amount of ink is an important issue.

A conventional ink jet printer will be described below with reference to the drawings. FIG. 4 is a block diagram showing the configuration of an ink ejection unit of a conventional ink jet printer. In the figure, 1 is a filled conductive ink, 2
Is an ink tank, 3 is an ejection port of a nozzle for ejecting ink drops, 4 and 5 are a pair of electrodes, 7 and 8 are a pair of electrodes for detecting the remaining amount of ink provided in the ink tank 2, and 10 is a remaining amount of ink. Is detected from the current amount of the current 9 flowing between the electrodes to notify the same, 12 is an alternating current pulse voltage generation for selectively applying an alternating current pulse voltage to the pair of electrodes by switching the polarity of the direct current power supply 11. A device, 6 is an energizing current generated in the conductive ink 1 when the AC pulse voltage is applied between the electrodes 4 and 5, and 9 is an electrode 7 and an electrode 8.
Is a direct current that is passed between and to detect the remaining amount of ink. Further, FIG. 5 is a circuit diagram showing a configuration of an AC pulse generator and an ink remaining amount detector in a conventional ink ejecting section.

The mutual relationship and operation of the above components will be described below. When the AC pulse voltage generator 12 is off, the inkjet printer is in a standby state. When the AC pulse voltage generator 12 is turned on, the electrodes 4 and 5 are
AC pulse voltage is applied between the pair of electrodes 4 and 5 and
Positive and negative energizing current 6 through the conductive ink 1 between
Flows. By repeating this pulse for several pulses with the positive and negative energizing currents as one pair, a part of the conductive ink 1 in the nozzle evaporates to generate bubbles, which causes a sharp volume change. The pressure of this volume change causes the other conductive ink 1 in the nozzle to be ejected from the ejection port 3 to form an ink droplet of 1 dot. When the AC pulse voltage generator 12 is turned off,
The energizing current 6 stops flowing, the bubbles generated in the conductive ink are deprived of the amount of heat by the surrounding conductive ink, and quickly disappear, and the inkjet printer returns to the standby state.
After that, ink is ejected by repeating these operations.

Next, the operation of the ink remaining amount detecting device 10 will be described with reference to FIG. In the figure, the CPU 13 outputs the AC pulse signal for printing and then turns on and off the transistor Tr7 to generate a DC pulse signal between the ink consumption detecting electrodes 7 and 8. Electrode 7
The current flowing between Nos. 8 and 8 is compared by the CPU 13 with a minimum allowable value that is a threshold value, and if it is smaller than the threshold value, it is considered that the ink has been exhausted.

[0006]

In such a conventional ink remaining amount detecting device for an ink jet printer, it is necessary to provide an ink remaining amount detecting electrode in the ink tank for detecting the remaining amount, which complicates the structure. At the same time, there was a problem that the cost would increase. The present invention solves the above problems, and an object of the present invention is to provide an inkjet printer having a configuration in which an electrode for detecting the remaining amount of ink is not provided in the ink tank.

[0007]

In order to achieve the above object, the present invention provides an ink tank containing a conductive ink, a plurality of nozzles connected to the ink tank, and a discharge nozzle in the nozzle. A pair of electrodes facing the outlet, and an alternating-current pulse voltage generator for applying a pulse voltage for alternately changing the polarity for ink ejection between the pair of electrodes,
An ink consumption detecting device is provided in an ink jet printer for performing 1-dot printing by causing an alternating current to flow through the conductive ink by the alternating pulse voltage to evaporate the ink between the electrodes to eject the ink and generate the alternating pulse. The apparatus applies a discharge voltage to the pair of electrodes and then applies a voltage for ink remaining amount detection, and the ink consumption detection device uses a current amount between the pair of electrodes based on the ink remaining amount detection voltage. To detect the remaining amount of ink, and the pair of electrodes also serves as an ink remaining amount detecting electrode.

[0008]

According to the present invention, in the above structure, the pair of electrodes act as electrodes for ejecting ink, and also serve as voltage applying electrodes for detecting the remaining ink amount after the ejecting operation.

[0009]

【Example】

(Embodiment 1) Hereinafter, an ink jet printer according to an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the construction of an ink ejection portion of an ink jet printer according to an embodiment of the present invention. In the figure, a nozzle 7 is connected to an ink tank 2, and the conductive ink 1 in the nozzle is connected to an AC pulse voltage generator 12
Is heated by the pair of electrodes 4 and 5 and expands to form the discharge port 3
Discharge from. The above-described configuration and operation are the same as the configuration and the ejection operation of the conventional inkjet printer, and the description thereof will be omitted. The present invention is different from the conventional ink jet printer in that only a pair of electrodes for ejecting ink are provided in the nozzle as shown in FIG. The amount is also trying to be detected.

FIG. 2 shows an ink consumption detecting device 1 in FIG.
0 and the configuration of the AC pulse voltage generator 12 are shown in a circuit diagram.

The mutual relationship and operation of the above components will be described below. In FIG. 2, when the L signal is output from the CPU 13 to the transistors Tr5 and Tr6, the pair of electrodes 4 and 5 are both set to the ground level, and the conduction current 6 does not flow between the electrodes 4 and 5. At this time,
The inkjet printer is in a standby state. Next CP
When an L signal is output from U13 to the transistor Tr5 and an H signal is output to the transistor Tr6, the electrode 4 changes to a positive potential level toward the electrode 5, the electrode 5 changes to the ground level, and a positive signal goes from the electrode 4 to the electrode 5. An energizing current 6 of flows. After the next predetermined time, the CPU 13 causes the transistor T
The H signal is output to r5 and the L signal is output to the transistor Tr6,
A negative energizing current 6 in the opposite direction to the energizing direction is passed. This alternating current causes a part of the conductive ink 1 in the nozzle 7 to evaporate and generate bubbles, which causes a sharp volume change.
The pressure of this volume change causes the other conductive ink 1 in the nozzle to be ejected from the ejection port 3 to form an ink droplet of 1 dot. Subsequently, the CPU 13 returns the signal to the transistor Tr5 from H to L, puts the inkjet printer in the standby state, and the operation of the first pulse is completed. After that, ink is ejected by repeating these series of operations. The stability of the electrodes is increased by repeatedly applying positive and negative energizing currents multiple times per dot. In this case, good results can be obtained by controlling the positive and negative total current values to be equal.

Next, the ink remaining amount detecting operation will be described with reference to FIG.
Will be described with reference to. FIG. 3A is a timing chart showing the operation of the remaining ink amount detection in the first embodiment. In the figure, the CPU 13 outputs a print AC pulse signal (indicated by a circle in the figure) based on the print data between the electrodes by the means shown in FIG. 2, and then a DC pulse signal for detecting the remaining ink amount (Δ in the figure). 1) is output. R1 in FIG. 2 is a resistor for detecting the remaining amount of ink. The current flowing between the electrodes 4 and 5 flows through the resistor R1 during the output of the print signal and the DC pulse signal. The current flowing through the resistor R1 gradually decreases as the ink is consumed,
The voltage value across the resistor R1 also decreases. Therefore, the ink remaining amount detecting means 10 can know the limit point of the ink remaining amount by checking the decrease of the voltage value. The minimum allowable voltage value, which is the limit, is determined in advance by an experiment in consideration of changes in print density. The CPU 13 detects the voltage value across the resistor R1 only when the DC pulse signal for detecting the remaining ink amount flows, and compares it with the minimum allowable voltage value to know the timing of ink replacement.

As described above, according to the ink jet printer of the first embodiment of the present invention, the ink tank containing the conductive ink, the plurality of nozzles coupled to the ink tank, and the nozzles in the nozzle are ejected. A pair of electrodes facing the outlet and an AC pulse voltage generator for applying a pulse voltage for alternately changing the polarity for ink ejection are provided between the pair of electrodes, and an AC current is applied to the conductive ink by the AC pulse voltage. In an ink jet printer for performing 1-dot printing by evaporating the ink in the electrodes to eject the ink by flowing the ink, an ink consumption detecting device is provided, and the AC pulse generating device supplies an ejection voltage to the pair of electrodes. After applying the voltage, a voltage for detecting the remaining ink amount is applied, and the ink consumption detecting device detects the voltage between the pair of electrodes by the voltage for detecting the remaining ink amount. The ink remaining amount is detected by detecting the current amount, and an ink remaining amount detecting electrode is provided in the ink tank by using an ink jet printer in which the pair of electrodes also serve as the ink remaining amount detecting electrodes. The remaining amount of ink can be detected without any effect, which has the effect of simplifying the structure.

(Second Embodiment) An ink jet printer according to a second embodiment of the present invention will be described below with reference to the drawings. The components of the ink jet printer according to the second embodiment of the present invention are the same as those shown in FIG. 1, except for the waveform of the ink consumption detection pulse output from the AC voltage generator 12.

The remaining ink amount detecting operation of the ink jet printer of the second embodiment of the present invention will be described below with reference to FIG. FIG. 3B is a timing chart showing the operation of detecting the remaining ink amount of the inkjet printer according to the second embodiment of the present invention. R1 in FIG. 2 is a resistor for detecting the remaining ink amount, and all the alternating currents flowing between the electrodes 4 and 5 can flow to the ground through the resistor R1. That is, a voltage is generated across the resistor R1 according to the value of the alternating current. Based on the print data, the CPU 13 applies a pair of AC pulse voltage from the AC pulse voltage generator to the electrodes for 6 pulses, ejects the ink to the outside of the nozzle, and then outputs 1 pulse of the AC pulse voltage for detecting the remaining ink amount. The voltage is applied from the AC voltage generator 12 to the pair of electrodes. At this time, the CPU 13 checks the voltage across the remaining ink level detection resistor R1. If the space between the pair of electrodes is filled with ink, a voltage is generated across the remaining ink amount detecting resistor R1, and the CPU 13 determines that there is ink remaining amount.
Continue printing. On the contrary, if ink is not filled between the pair of electrodes, no voltage is generated across the remaining ink amount detection resistor R1, the CPU 13 determines that there is no remaining ink amount, ends the printing operation, and replaces the ink. Inform when.

In the embodiment, the number of AC pulse voltage pulses for detecting the remaining amount of ink is one pulse (one pair of positive and negative pulses), but this is because the ink boiling condition (ink ejection condition) between the electrodes in the embodiment is It is needless to say that the number of pulses is determined based on the condition example of 6 pulses or more and other numbers of pulses may be used.

Further, as another embodiment, the pulse voltage value of the AC pulse voltage device for ink remaining amount detection is changed from that at the time of printing, and an AC pulse voltage value at which ink does not boil and evaporate is applied to a pair of electrodes, Similar results can be obtained by detecting the remaining ink amount.

[0019]

As is apparent from the above embodiments, the present invention provides an ink tank containing a conductive ink, a plurality of nozzles connected to the ink tank, and a nozzle in the nozzle that faces the ejection port. And a pair of electrodes, and an alternating-current pulse voltage generator for applying a pulse voltage for alternately ejecting the ink between the pair of electrodes. By applying an alternating current to the conductive ink by the alternating pulse voltage, In an ink jet printer for performing 1-dot printing by evaporating the ink between the electrodes to eject the ink, an ink consumption detecting device is provided, and the AC pulse generating device applies an ejection voltage to the pair of electrodes. By applying a voltage for detecting the remaining amount of ink, the ink consumption detecting device detects the amount of current between the pair of electrodes based on the voltage for detecting the remaining amount of ink. By using an ink jet printer in which the pair of electrodes also function as the ink remaining amount detecting electrodes by detecting the ink remaining amount, an electrode dedicated to the ink remaining amount detection is not required, and the effect of simplifying the configuration of the device is obtained. is there.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of an ink ejection unit in an inkjet printer according to first and second embodiments of the present invention.

FIG. 2 is a circuit diagram showing a configuration of an AC pulse generator and an ink remaining amount detecting device in the inkjet printer according to the first and second embodiments of the present invention.

FIG. 3 is a timing chart showing operations of ink ejection and ink remaining amount detection in the inkjet printers of the first and second embodiments of the present invention.

FIG. 4 is a block diagram showing a configuration of an ink ejection unit of a conventional inkjet printer.

FIG. 5 is a circuit diagram showing configurations of an AC pulse generator and an ink remaining amount detector of a conventional inkjet printer.

[Explanation of symbols]

1 Conductive ink 2 ink tank 3 outlets 4,5 pair of electrodes 6 Current flowing through conductive ink 7 nozzles 10 Ink remaining amount detection device 12 AC pulse voltage generator

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hideaki Horio             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor, Shoji Oyama             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd. (72) Inventor Koei Matsuda             1006 Kadoma, Kadoma-shi, Osaka Matsushita Electric             Sangyo Co., Ltd.

Claims (2)

[Claims] 1. An ink tank containing a conductive ink, a plurality of nozzles connected to the ink tank, a pair of electrodes in the nozzle facing the ejection port, and an ink between the pair of electrodes. An alternating-current pulse voltage generator for applying a pulse voltage whose polarity is alternately changed for ejection is provided,
An ink consumption detecting device is provided in an ink jet printer for performing 1-dot printing by causing an alternating current to flow through the conductive ink by the alternating pulse voltage to evaporate the ink between the electrodes to eject the ink and generate the alternating pulse. The apparatus applies a discharge voltage to the pair of electrodes and then applies a voltage for ink remaining amount detection, and the ink consumption detection device uses a current amount between the pair of electrodes based on the ink remaining amount detection voltage. An ink jet printer in which the remaining amount of ink is detected by detecting the above, and the pair of electrodes also serve as the remaining ink amount detecting electrodes. 2. The ink jet printer according to claim 1, wherein the remaining ink amount is detected by an alternating current flowing between a pair of electrodes.