JPH02208052A - Liquid jet recorder - Google Patents

Abstract

PURPOSE:To detect the recording defect of an electric system that cannot be restored and to eliminate useless restoration operation, time and ink consumption, by detecting the breakage of a heating resistance based on a current detecting signal and issuing the alarm based on an alarming signal indicating the breakage. CONSTITUTION:A current detecting circuit 2 is connected to a power supply line L communicating with the heating resistance 15 of a recording head from a power source 19. When a controller 20 impresses a breakage check instruction signal 6 on a heat timing signal generating circuit 3 in its home position, for instance, during printing down-time, heat timing signals are sequentially sent pulse by pulse to the heating resistance 15 from the heat timing signal generating circuit 3. According to the heat timing signal 5, the current detecting circuit 2 detects a current flowing into each heating resistance 15, and outputs a current detecting signal 4. The heat timing signal 5 and the current detecting signal 4 are inputted to a heating resistance breakage detecting circuit 2, which detects the breakage of the heating resistance 15 and generates the alarming signal 7.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a liquid jet recording device that records various information by ejecting droplets of recording liquid onto a recording material such as paper. .

[Prior Art] In a liquid jet recording apparatus, ink (recording liquid) is discharged from orifices (discharge ports) provided in a recording head.

Recording is performed by ejecting droplets and adhering the ejected droplets to a recording material such as paper, which generates extremely little noise and enables high-speed recording.Moreover, it uses Sotong paper. Various types of recording heads and liquid jet recording methods have been proposed to date.

Among these, a type of print head that applies thermal energy to ink and ejects it from the orifice has advantages such as good responsiveness to a print signal and easy multiplication of orifices at a high density.

A typical configuration of such a type of recording head that uses thermal energy as ink ejection energy is shown in Figure 3 (
Figure 3 (^) shows a cross section of the recording head in the flow path direction, and Figure 3 (B) shows the bonding positional relationship between the substrate and the top plate. It is something.

This recording head has electrothermal transducers arranged on a substrate 18, and finally a flow path 13 in this electrothermal transducer.
A protective layer 11 is provided above the heating resistor 15 and the electrode 10 located below the liquid chamber 17, and a top plate 12 on which a flow path 13 and a liquid chamber 17 are formed is joined to the top of these.

The ink ejection energy in this recording head is generated by a pair of electrodes IO and a heating resistor 15 located between these electrodes.
It is applied by an electrothermal converter having. Sunawa 4
When a current is applied to the electrode lO to cause the heating resistor 15 to generate heat, the ink in the flow path 13 near the heating resistor 15 is instantaneously heated and bubbles are generated there. Ink droplets are ejected from the orifice due to volume changes caused by instantaneous volumetric expansion and contraction.

In a liquid jet recording device (also referred to as an inkjet printer) using such a recording head, there are problems such as clogging of the ink ejection openings such as orifices provided in the recording head, and air bubbles in the ink supply path leading to the ink ejection openings. Contamination or the like may deteriorate droplet ejection performance and cause ink ejection failure.

Therefore, in conventional liquid jet recording devices, a suction means that can face the ejection port is provided outside the ejection port to suck ink from the ejection port, or the ink is removed to a certain extent by pressurizing the inside of the ink supply path. By flowing the ink at a high speed and discharging it from the discharge port, the cause of the ink discharge failure as described above is eliminated.

[Problems to be Solved by the Invention] However, in the liquid jet recording device as described above, recoverable ink is caused by dust near the ink ejection ports or air bubbles mixed into the ink supply path leading to the ink ejection ports. It was not possible to determine or distinguish between an ejection failure and an unrecoverable ink ejection failure due to failure of the electrical system, such as breakage or deterioration of a heating resistor, or short-circuit or disconnection of an electrode. Therefore, in conventional apparatuses, when an ink ejection failure occurs, a recovery operation is always performed to recover from the ejection failure by suctioning ink from the ejection port or pressurizing the inside of the ink supply path.

Therefore, conventionally, in the case of an electrical failure such as the above-mentioned breakage of the heating resistor, which cannot be recovered, the above-mentioned recovery operation has to be performed several times, which is a complete waste of ink and time. I was wasting it.

In view of the above-mentioned problems, an object of the present invention is to make it possible to detect unrecoverable recording defects in the electric system due to breakage or deterioration of the heating resistor, and to eliminate meaningless recovery operations so that the ink can be removed. To provide a liquid jet recording device capable of eliminating unnecessary waste of time.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an ejection port for ejecting recording liquid and a heat exchanger provided corresponding to the ejection port that is used for ejecting the recording liquid. In a liquid jet recording device equipped with a recording head having a heat generating resistor that generates energy and a drive circuit that drives the head, there is provided a current detecting means for detecting the value of the current flowing through the heat generating resistor, and a current output from the current detecting means. A break detection means for detecting breakage of the heat generating resistor based on a detection signal, and a warning means for notifying a warning based on a warning signal indicating breakage of the heat generating resistor outputted from the break detection means. It is characterized by

[Function] With the above configuration, the present invention can promptly detect the breakage of the heat generating resistor when any one of the plurality of heat generating resistors breaks and the discharge fails, and thus the failure occurs. It is possible to prevent unnecessary ejection recovery operations for ejection recovery and wasteful consumption of ink due to ejection recovery operations.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

As a recording head of a liquid jet recording apparatus to which the present invention can be applied, for example, one having a structure similar to that of the conventional example shown in FIGS. 3(^) and 3(B) is used. More specifically, in the figure, the substrate 1318 is made of silicon. 9 is a base layer made of silicon oxide (5f(h)).

The heating resistor 15 is made of hafnium boride (HfB2) and is patterned on the upper surface of the base layer 9. Electrode 1
G is a counter electrode electrically connected to this heating resistor 15, and is made of a good conductor such as aluminum.

The protective layer 11 is the heating resistor 15 and the counter electrode! 0, and can be omitted if necessary. Reference numeral 14 denotes channel walls made of resin or the like, and a channel 13 is formed between these channel walls 14, and an orifice (discharge port) is formed at the tip of this channel 13. The top plate 12 is made of glass.

FIG. 1 shows an embodiment of the configuration of a circuit for detecting breakage of a heating resistor in a liquid jet recording apparatus to which the present invention is applied.

In the figure, 1 is a heating resistor 15 (third
This is a current detection circuit that detects the level value of the current flowing through the circuit (see figure). 2 is a warning signal 7 which compares the level of the current detection signal 4 output from the current detection circuit 1 with the level of the heat timing signal 5 and indicates that the heating resistor 15 has broken.
This is a rupture detection circuit that outputs .

The current detection circuit 1 described above is connected to a power supply line L that connects a power source 19 to a heating resistor 15 of the recording head. When not printing, for example at the home position,
When the breakage check command signal 6 is applied from the controller 20 to the heat timing generation circuit 3, the heat timing signal 5 is sequentially sent from the heat timing signal generation circuit 361 to the heat generating resistor 15 by 1 pulse each. and,
A current detection circuit 1 detects the current flowing through each heating resistor 15 according to its heat timing signal 5, and outputs a current detection signal 4.

The above-mentioned heat timing signal 5 and current detection signal 4 are input to the rupture detection circuit 2, and the rupture detection circuit 2 detects the rupture of the heating resistor 15 and generates the warning signal 7. If the resistor is broken, the second
As shown in the figure, the resistance value of the third heating resistor changes due to the rupture, causing an electric current.

The third output level of flow detection signal 4 decreases or becomes 0.
Therefore, the breakage detection circuit 2 determines that there is a breakage, and a warning signal 7 is generated to the warning means 21.

As the warning means 21, for example, an LED alarm lamp 22, 32 attached to the operation panel 34 of the liquid jet recording apparatus as shown in FIGS. 4(^) and 4(B) can be used. In this case, the warning signal 7 causes the alarm lamp 22 to turn on or flash, thereby indicating that the heating resistor of the head is broken. Further, as the warning means 21, a buzzer or a message printed on recording paper may be used.

In addition, in the present embodiment described above, as a method for detecting the current of a heating resistor in the case of a multi-nozzle, one heating resistor is used.
Although the current value is detected sequentially for each heat generating resistor, the present invention is not limited to this. For example, the entire current value flowing through the heat generating resistors when a driving pulse is simultaneously applied to every several heat generating resistors may be detected. By comparing this detected current value with a predetermined threshold value, it is possible to detect the presence or absence of a break in the resistance value, thereby further shortening the break detection time.

In addition, in the above embodiment, the breakage detection operation is performed when the print head is located at the home position, but if this detection operation is performed at the same time as the normal ink ejection recovery operation, it will be more efficient. It is true.

[Effects of the Invention] As explained above, according to the present invention, when any one of the plurality of heating resistors breaks and non-ejection occurs,
Breakage of the heating resistor can be quickly detected, and the effect of preventing unnecessary ejection recovery operations for recovery from non-ejection and wasteful consumption of ink due to ejection recovery operations can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing the circuit configuration of a circuit for detecting breakage of a heat generating resistor according to an embodiment of the present invention, and FIG. 2 is a block diagram showing the circuit configuration of a circuit for detecting breakage of a heat generating resistor according to an embodiment of the present invention. 3 shows a schematic configuration of a recording head of a liquid jet recording apparatus to which the present invention can be applied, FIG. 3A is a partial cross-sectional view, and FIG. CB) is a developed partial view. FIG. 4 shows the appearance and operation panel of a liquid jet recording apparatus according to an embodiment of the present invention, with FIG. 4(A) being a perspective view and FIG. 4(B) being a plan view. 9...Sj base layer, lO...electrode, 11...protective layer, 12...top plate, 13...channel, 14...channel wall, 15...heating resistor, 17... Liquid chamber, 18... Board, 19... Power supply, 20... Controller, 32... Alarm lamp, 34... Operation panel. 1... Current detection circuit, 2... Break detection circuit,

Claims (1)

[Scope of Claims] 1) A recording head having an ejection opening for ejecting recording liquid and a heating resistor provided corresponding to the ejection opening and generating thermal energy used for ejecting the recording liquid. and a drive circuit for driving the head, comprising: current detection means for detecting the value of the current flowing through the heating resistor; and based on a current detection signal output from the current detection means,
It is characterized by comprising a breakage detection means for detecting breakage of the heat generating resistor, and a warning means for notifying a warning based on a warning signal indicating the breakage of the heat generating resistor outputted from the breakage detection means. A liquid jet recording device.