JP2000289218A - Ink-jet recording apparatus and ejection failure detection method for the recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable quick and accurate detection of a recording head ejection failure. SOLUTION: Data concerning the temperature of a recording head 15 are provided by a temperature detecting element 1502 provided in the recording head and a temperature detecting element controlling circuit 1600. The data are stored in a sample/hold circuit 1601 at timings immediately before and immediately after a recording operation for each block. The difference between the two data as the temperature rise data of the recording head 15 before and after the recording operation is compared with ordinary temperature rise data without an ejection failure by a comparison judgment circuit 1602. In the case the temperature rise before and after the recording operation is large, it is judged that the ink ejection failure is generated so as to advise the same to a CPU 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording apparatus and a method for detecting a discharge failure of the recording apparatus, and more particularly to a recording apparatus capable of detecting a discharge failure of a recording head which discharges ink using thermal energy. And a method for detecting an ejection failure of the printing apparatus.

[0002]

2. Description of the Related Art In a recording apparatus of a type in which a heating element is provided in a recording head and recording is performed using thermal energy, the temperature of the recording head changes due to heat generated by the heating element. Since such a temperature change affects the print quality and the life of the print head, the temperature change of the print head is monitored, and control is performed so that the driving conditions are optimized.

[0003] Among such recording apparatuses, in particular, in an ink jet recording apparatus having a recording head that discharges ink by using thermal energy, if even one of the nozzles that discharge ink has a discharge failure, correct printing is performed. If not only (good) printing is not performed, but also the printing operation is performed continuously, the temperature of the nozzles that have failed in ejection may rise sharply and destroy the print head in some cases.

[0004] Therefore, in such a printing apparatus, a recovery operation and a preliminary ejection are periodically performed so that an ejection failure does not occur during printing.

[0005] In addition, the apparatus is provided with a function of detecting a discharge failure at the time of preliminary discharge, and detecting a discharge failure during printing. If a discharge failure is detected, the recording operation is interrupted to perform a recovery process. Devices also exist.

[0006] In such a printing apparatus, ejection failure detection performed at the time of preliminary ejection is performed at regular intervals during the preliminary ejection.
Alternatively, the temperature of the recording head is measured before and after the preliminary ejection, and the presence or absence of ejection failure is determined based on whether or not the temperature change during that period exceeds an appropriate range.

[0007] On the other hand, the detection of a discharge failure performed during printing is performed by measuring the temperature of the print head at regular intervals and determining the presence or absence of a discharge failure based on whether or not the temperature is abnormal.

[0008]

The temperature of a recording head that ejects ink using thermal energy follows a recording pulse applied to a heater or the like, which is a heating element provided for each nozzle, and a current is applied to the heater. During the supply, the temperature rises sharply, but when the recording pulse ends and the current supply to the heater stops, the temperature immediately drops.

However, the ejection failure detection in the above-described conventional printing apparatus does not measure the instantaneous temperature immediately before and immediately after the application of a print pulse, and cannot detect a rapid change in temperature due to driving of the heater.

For this reason, the apparatus is configured to detect a change in temperature due to heat accumulated in the entire recording head in a certain period of time to determine the presence or absence of a discharge failure. Therefore, when performing ejection failure detection at the time of preliminary ejection, it is necessary to increase the number of ejected ink droplets in order to increase the heat accumulated in the recording head to a certain degree or more, which has an effect on throughput. Only when the power is turned on or when the recovery process is performed, the ejection failure can be detected.

In addition, even when an ejection failure is detected during printing, a temperature change due to heat accumulated in the entire print head is detected to determine the presence or absence of an ejection failure. If the nozzle does not cause ejection failure, the temperature rise of the entire recording head is not remarkable, and therefore, it cannot be detected.

Therefore, in the above-described conventional ejection failure detection, despite the fact that there is a nozzle in which ejection failure has actually occurred,
In some cases, the recording operation is continued. This not only wastes recording media and recording time by performing unnecessary recording, but also causes damage to the recording head and shortens the service life.

In recent years, in particular, the recording head tends to increase in density as the number of nozzles increases, and the price tends to increase accordingly. Therefore, it is desired to detect an ejection failure at an earlier stage so as not to damage the recording head.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an ink jet recording apparatus capable of quickly and accurately detecting a discharge failure of a recording head, and a method of detecting a discharge failure of such a recording apparatus. The purpose is to provide.

[0015]

According to another aspect of the present invention, there is provided an ink jet recording apparatus for performing recording by a recording head which discharges ink by using thermal energy, wherein the recording head comprises: A temperature measuring means for obtaining data relating to the temperature of the first unit, and controlling the temperature measuring means so as to obtain first temperature data before performing recording in a predetermined unit, and to obtain second temperature data after performing the recording. Measurement control means, difference means for obtaining a difference between the first and second temperature data, and comparing the difference with a predetermined value, and when the difference is larger than the predetermined value, ink is supplied to the recording head. And determination means for determining that a discharge failure has occurred.

Further, a method for detecting a discharge failure of an ink jet recording apparatus according to the present invention which achieves the above object is a method for detecting a discharge defect in an ink jet recording apparatus which performs recording by a recording head which discharges ink using thermal energy. A first temperature measurement step of obtaining first temperature data relating to the temperature of the printhead before performing printing in a predetermined unit;
A second temperature measurement step of obtaining second temperature data relating to a temperature of the recording head after performing the recording;
And a difference step of obtaining a difference between the second temperature data and comparing the difference with a predetermined value, and when the difference is larger than the predetermined value, determining that an ink ejection failure has occurred in the recording head. And a determining step of performing the determination.

That is, in an ink jet recording apparatus that performs recording with a recording head that discharges ink by using thermal energy, data on the temperature of the recording head is obtained before and after recording in a predetermined unit by the recording head, and before and after recording. The difference between the two data, which is the printhead temperature rise data, is compared with the normal rise temperature data when there is no discharge failure, and when the temperature rise before and after printing is large, a printhead ink discharge failure occurs. It is determined that it has been performed.

Thus, the temperature rise of the print head before and after printing can be monitored successively, so that a discharge failure can be detected even in preliminary discharge in which the number of ink droplets to be discharged is small. Further, even during the printing operation, it is possible to quickly and accurately detect a discharge failure.

Therefore, it is possible to prevent unnecessary recording and wasting the recording medium and the recording time by performing unnecessary recording, and to reduce the damage to the recording head and extend the life of the recording head. .

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is an external perspective view showing an outline of the configuration of an ink jet printer IJRA which is a typical embodiment of the present invention.

In FIG. 1, a spiral groove 500 of a lead screw 5005 which rotates through driving force transmission gears 5009 to 5011 in conjunction with forward and reverse rotation of a driving motor 5013.
The carriage HC engaged with the carriage 4 has a pin (not shown), and is supported by the guide rail 5003 to reciprocate in the directions of arrows a and b. The recording head 1 is mounted on the carriage HC.
5 and an integrated ink jet cartridge IJC containing an ink tank IT. A paper pressing plate 5002 presses the recording paper P against the platen 5000 in the moving direction of the carriage HC. 500
7,5008 is a photocoupler, which is a lever 5 of the carriage.
006 is a home position detector for confirming the existence in this area and switching the rotation direction of the motor 5013.

Reference numeral 5016 denotes a member for supporting a cap member 5022 for capping the front surface of the recording head 15.
Reference numeral 5 denotes a suction device that suctions the inside of the cap, and performs suction recovery of the recording head through the opening 5023 in the cap. 50
Reference numeral 17 denotes a cleaning blade. Reference numeral 5019 denotes a member that allows the blade to move in the front-rear direction. These members are supported by a main body support plate 5018. It goes without saying that the blade is not limited to this form and a known cleaning blade can be applied to this example. Reference numeral 5021 denotes a lever for starting suction for recovery of suction. The lever 5021 moves with the movement of the cam 5020 that engages with the carriage, and the driving force from the driving motor is controlled by a known transmission mechanism such as clutch switching. Is done.

The capping, cleaning, and suction recovery are configured so that desired operations can be performed at the corresponding positions by the action of the lead screw 5005 when the carriage comes to the area on the home position side. If a desired operation is performed at the timing, any of the embodiments can be applied.

Next, a control configuration for executing the recording control of the above-described apparatus will be described.

FIG. 2 is a block diagram showing a configuration of a control circuit of the ink jet printer IJRA. In FIG. 1 showing a control circuit, reference numeral 10 denotes an interface circuit to which an external recording signal is input, 11 denotes a CPU, and 12 denotes a CPU1.
A ROM 13 stores a control program executed by the CPU 1 and a RAM 13 stores various data (the recording signal and recording data supplied to the head).

Reference numeral 14 denotes a head drive control circuit comprising a gate array (GA) for controlling the supply of print data to the print head 15;
It also controls data transfer between U11 and RAM13. Reference numeral 20 denotes a carriage motor for transporting the recording head 15;
9 is a control circuit of the carriage motor, 19 is a paper feed motor for conveying the recording paper, and 17 is a drive circuit of the paper feed motor. 1500 is a head driver for driving the print head, and 1501 is a print element driven by the head driver.

The ink jet printer of this embodiment is
A temperature detecting element 1502 for detecting the temperature of the recording head is provided inside the recording head 15.
Is connected to a head temperature detection circuit that transmits the obtained temperature information to the CPU 11 and controls the temperature detection element 1502.

A key 24 is connected via an input control circuit 23 so that the user can input settings and instructions.
2 are connected via an output control circuit 21.

The operation of the above-described control structure will be described. When a recording signal enters the interface 10, the head drive control circuit 1
4 and the CPU 11 convert the recording signal into recording data for printing. Then, the motor drive circuits 17 and 19
Is driven, and the recording head 15 is driven according to the recording data sent to the head driver 1500 to perform recording.

Here, the control program executed by the CPU 11 is stored in the ROM 12.
An erasable / writable storage medium such as an OM may be further added so that the control program can be changed from a host computer connected to the recording apparatus.

As described above, the ink tank IT and the recording head 15 may be integrally formed to form a replaceable ink cartridge IJC. However, the ink tank IT and the recording head 15 may be separated. It may be configured so that only the ink tank IT can be replaced when the ink runs out.

FIG. 9 is an external perspective view showing the structure of an ink cartridge IJC in which the ink tank and the head can be separated. As shown in FIG. 3, the ink cartridge IJC holds the ink tank IT and the recording head 1 at the position of the boundary line K.
5 is separable. When the ink cartridge IJC is mounted on the carriage HC, an electrode (not shown) for receiving an electric signal supplied from the carriage HC is provided.
As described above, the recording head 15 is driven to eject ink.

In FIG. 9, reference numeral 500 denotes an ink ejection port array. The ink tank IT is provided with a fibrous or porous ink absorber for holding ink, and the ink is held by the ink absorber.

Hereinafter, the portion for detecting the temperature of the recording head in this embodiment will be described in detail.

The temperature sensor 1502 shown in FIG.
5 is an element for detecting the temperature, such as a thermistor,
It is composed of a diode and the like. The head temperature detection circuit 16 controls the temperature detection element 1502 and
Temperature information obtained from the CPU 11 as a voltage
Notify. The transmitted information is A / D converted by the CPU 11 and used for each control. Note that the CPU normally checks this temperature information at regular time intervals.

In the present invention, the head temperature detecting circuit 16
Not only outputs head temperature information, but also compares the head temperature at a certain point in time with the head temperature at another point in time, and when the temperature difference between them is greater than a reference threshold value, Is notified to the CPU.

FIG. 3 is a block diagram showing in detail the internal structure of the head temperature detecting circuit block 16 of FIG. 2 together with peripheral parts. Hereinafter, description will be made with reference to FIG.

The head temperature detecting circuit 16 includes a temperature detecting element control circuit 1600, a sample / hold circuit 1601,
And a comparison determination circuit 1602.

The temperature sensing element control circuit 1600 includes a CPU 11
In accordance with the instruction from, the voltage and current supplied to the temperature detecting element 1502 are controlled, and the electrical characteristics indicated by the temperature detecting element 1502 are set to values that can be recognized by the CPU 11, for example,
It has a function of performing conversion by performing amplification, offset, and the like.

The sample / hold circuit 1601 has a function of sampling / holding the head temperature information output from the temperature sensor control circuit 1600 as necessary. While the sample is selected, the head temperature information input from SG2 is transmitted directly to CPU 11 via SG4. When the hold is selected, the head temperature information input immediately before the hold is held and continuously output to SG4.

The comparison / determination circuit 1602 includes the head temperature information at a certain point in time held by the sample / hold circuit 1601 and the head temperature information at another point (or the head temperature information currently being sampled). , And when the temperature difference is larger than the preset temperature difference, it is determined that the state is abnormal, and the CPU 11
To issue a symphony.

In this embodiment, the head drive control circuit 14 controls the sample / hold timing of the sample / hold circuit 1601 and the timing of judgment and warning generation by the comparison / judgment circuit 1602.

FIG. 4 is a diagram showing a specific circuit example of the head temperature detecting circuit 16 described in FIG.

In FIG. 4, a temperature sensor control circuit 1600
Comprises a constant current circuit for supplying a constant current to a diode serving as a temperature detecting element 1502, and an amplifier circuit for amplifying a voltage drop caused by the diode. The current value of the constant current circuit is C
It can be set to DA1 by the PU11 or the like.

The sample / hold circuit 1601 includes a gate circuit for sampling / holding temperature information (voltage) output from the temperature sensor control circuit 1600, a capacitor for holding a voltage when the gate is opened, It consists of a buffer circuit that does not let the charge of the capacitor escape.

In this embodiment, two sets of such a circuit composed of a gate, a capacitor, and a buffer are prepared, and the sample / hold can be performed at two different timings. The head temperature information sampled / held at two timings is compared with the comparison / judgment circuit 1 in the next stage.
602 is input. One of the two is transmitted to the CPU 11 via the SG 4 as head temperature information.

A comparison / judgment circuit 1602 compares a temperature difference between two pieces of temperature information held in the sample / hold circuit 1601 at different timings, and determines whether the difference is larger than a threshold value. And a comparator for determining whether or not the difference is greater than a threshold value, the state is latched,
It comprises a latch circuit for issuing a warning to the CPU 11.

The threshold value can be set to a predetermined value DA2 by the CPU 11 or the like, and the warning flag output of the latch circuit can be reset by the control of the CPU 11 or the like (CL signal).

FIG. 5 is a timing chart showing the relationship between the driving of the recording head and the operation of the head temperature detecting circuit.

In the figure, BLE0-3 are block select signals for the recording head, HE is a drive signal, SH_A and SH_B.
Is a sample / hold signal, SG4, SG10, SG1
1, SG13 and SG5 are signals of the portion shown in FIG. 4, respectively, and CL is a reset signal of SG5.

In this embodiment, the recording element of the recording head is divided into 16 blocks, and heat (recording) pulses are applied in the block order corresponding to the value of the 4-bit block selection signal (BLE0-3). Drive. Drive signal (H
E) is a signal that determines the drive timing and drive time width of each element, and is driven when the signal is “High”. However, the elements that are actually heated are those that satisfy the three conditions of the block selection signal (BLE0-3), the drive signal (HE), and the recording data.

Sample / hold signal A (SH_A)
Is a first signal for sampling / holding the temperature information of the head. In this case, the sample is in the "Low" state and the hold is in the "High" state.

The drive signal (HE) becomes "High",
While the recording element is being heated, the temperature of the head rapidly rises and the output of the temperature detection element control circuit 1600 becomes unstable, so that SH_A becomes “High” and the sampling during that period is masked. That is, during that time, the head temperature immediately before driving is held. Then, the drive signal HE
SH_A becomes “Low” immediately after the signal becomes “Low”, and starts sampling. The signal SG4 indicates the output by the first sample / hold.

Sample / hold signal B (SH_B)
Is a second signal for sampling / holding the temperature information of the head. This signal also holds the head temperature immediately before driving the head. Then, the driving signal HE becomes “Lo”
w ”and SH_A also goes“ Low ”a predetermined time after SH_A goes“ Low ”, and starts sampling, and signal SG10 indicates the output of this second sample / hold.

SG11 is the head temperature by the first sampling immediately after the head drive of SG4 and the second temperature of SG10.
3 shows a signal obtained by amplifying a difference between the head temperature and the head temperature due to the sampling by the operation amplifier. That is, this signal corresponds to an increase in head temperature due to recording.

SG13 is the output SG11 of the operational amplifier.
And a signal SG12 corresponding to a predetermined threshold value DA2, which is compared with a signal SG12 by a comparator. When SG11 is larger than SG12, the signal becomes “High”.

SG5 is an output signal of the comparison / determination circuit 1602. When the output signal SG13 from the comparator is latched by the latch timing signal LT, "High" is output.
h ”, a warning flag is transmitted to the CPU. In this case, the timing of LT is determined by the sample / hold signal B.
(SH_B) is shown as falling, but SG1
Any other timing may be used as long as the signal of No. 3 can be latched.

CL outputs the signal held by the latch to “H”.
This signal is a signal that is cleared when the signal becomes "high".
Is set to “High” after confirming the warning flag SG5.

This figure shows the change of each signal when there is an ejection failure nozzle in the fifteenth block of the recording head. While the fifteenth block is being driven due to the effect of the nozzles having a discharge failure, the temperature rise of the recording head indicated by SG4 becomes large, and the output of SG11 becomes larger than the threshold value. Accordingly, the comparator output SG13
Becomes "High", and the output SG5 of the comparison and judgment circuit is inverted to the "High" state at the timing of the latch LT. In this state, the clear signal CL of the latch is “Low”.
It is held until it becomes.

As described above, in the present embodiment, the print head is divided into a plurality of blocks and driven, and the temperature data of the print head immediately before and immediately after the drive is compared for each block. If it is larger than the predetermined threshold value, it is determined that there is a nozzle in the recording head where ejection failure has occurred, and a warning flag is issued to the CPU.

This makes it possible to quickly and accurately determine the presence or absence of a discharge failure every time each block is driven.
When an ejection failure is detected, a recovery process is performed on the print head, and the ejection failure can be repaired within a short time, and printing can be performed again.

Here, the ejection failure detection of the present embodiment will be described again with reference to the flowchart of FIG. Here, the processing performed by the head temperature detection circuit 16 in units of 16 blocks will be described.

First, in step S101, the two sample / hold circuits are set to the hold state, and the temperature data of the recording head before driving is held.

Next, in step S102, one block of nozzles is driven by a heat pulse by calculating the logical product of the selection signal and the print data.

Then, in step S103, one of the sample / hold circuits is brought into a sample state by the first sample / hold signal. At this time, the signal input to the differential amplifier becomes two temperature data before and after driving.

After a lapse of a predetermined time, in step S104, the other sample / hold circuit is brought into a sample state by the second sample / hold signal. At this time, the comparator output is also latched at the same time.

In step S105, it is determined whether the output of the comparator is "High". If the output is "High", a warning flag is set to ON in step S106, indicating that a discharge failure has been detected.

Next, in step S107, it is determined whether or not the driving of the previous block has been completed. If the driving has not been completed, the process returns to step S101 again to detect a discharge failure for the next block. If all blocks have been completed, the processing is terminated and the arrival of the next recording data or block selection signal is waited.

Hereinafter, a modified example of the head temperature detecting circuit 16 in the recording apparatus of the present invention will be described.

The first modified example is different from the first embodiment in the timing of detecting the temperature of the recording head, and the configuration and operation of the other parts are the same as in the first embodiment. Then, the description is omitted.

FIG. 6 is a diagram showing a specific circuit example of the temperature detection circuit 16 of the present modification. Basically, it is the same as that described in FIG.
(SH_B) is a first signal (SG4) for sampling / holding the temperature information of the recording head, and a new sample / hold signal C (SH_C) is a second signal (SH_C) for sampling / holding the temperature information of the head. SG10).

FIG. 7 is a timing chart showing a change in a signal in each part of the circuit of FIG. Similar to the first embodiment, it is assumed that there is an ejection failure nozzle in the fifteenth block of the print head. Here, portions different from the timing chart of FIG. 5 in the first embodiment will be described.

Sample / hold signal C (SH_C)
Is a hold state in which the previous state is held when "High", and a value corresponding to the input signal is "Low", like the sample / hold signals A and B of the first embodiment. This is the sample state to be output.

In this modification, the period when SH_C is “High” is after the drive signal HE has become “Low” within the period when SH_B is “High”.
As a result, the temperature of the recording head immediately after driving is held.

Therefore, the signal SG10 which is brought into the sample or hold state by SH_C is constant for a short time immediately after the recording head is driven as shown in FIG. 7, and changes at other times with the temperature of the recording head. I do. The output signal SG11 from the differential amplifier also fluctuates longer than in the first embodiment. The output SG13 of the comparator SG_C is “H”.
During the period of “high”, it is stable at a certain level.

This is because the signals SG4 and SG10 are input to the comparator of the comparison and judgment circuit while being held at the temperature immediately after driving and the temperature immediately before driving, respectively, so that the comparison result in the comparison and judgment circuit becomes stable. It is.

As described above, according to this modification, the comparison result in the comparison and judgment circuit for comparing the temperatures before and after driving the recording head is stabilized, and the judgment can be made accurately.

Next, a second modification of the temperature detecting circuit 16 will be described.

The specific circuit configuration of the head temperature detecting circuit 16 of this modification is the same as the configuration shown in FIG. 4 of the first embodiment, and the description is omitted here. However, the timing of the sample / hold signal A (SH_A) and the timing of the sample / hold signal B (SH_B) are different from those in the first embodiment.

FIG. 8 is a timing chart showing a change in a signal in each part of the circuit of FIG. Here, portions different from the timing chart of FIG. 5 in the first embodiment will be described.

This modification detects a nozzle ejection failure even when the drive signals (HE) of 16 blocks are continuously generated and it is difficult to compare the temperature information before and after each drive signal. Is possible.

As shown in FIG. 8, the drive signal HE of the recording head is "High" for substantially the same period as the period in which the block to be driven by the block selection signals (BLE0-3) is selected.

Therefore, in the present modification, the ejection failure is not detected for each block, and the temperature information of the recording head sampled before and after the period related to the driving of the entirety of the 16 blocks is compared. On the other hand, ejection failure detection is performed.

For this reason, the first sample / hold signal A (SH_A) becomes “High” while the 16 blocks are sequentially driven, keeps the hold state, and the driving of all the blocks is completed. Immediately after that, the temperature becomes “Low”, and the temperature information of the recording head whose temperature has been increased by heating is sampled.

On the other hand, the second sample / hold signal B
(SH_B) is the first sample / hold signal A (S
H_A) becomes “Low” for a short period after “Hig”
After the state “h” is maintained, the state is switched to “Low”.

As in the first embodiment described above, the state of the comparator output SG13 when the second sample / hold signal B (SH_B) becomes "Low" is latched, so that discharge is performed to any of the blocks. When there is a defective nozzle, the output SG5 of the comparison / determination circuit 16
Becomes “High” when the second sample / hold signal B (SH_B) becomes “Low”.

As described above, according to the present modification, since the temperature information is sampled only once after all the blocks have been driven, when the blocks are continuously driven to perform high-speed recording. In addition, it is possible to quickly detect a discharge failure of the recording head.

Various timings for controlling the first and second sample / hold signals can be considered in addition to the above-described embodiments and modified examples. In consideration of the rapid change of the print head, the temperature change of the print head is monitored for each unit in which the print elements such as the nozzles are continuously driven, and the discharge failure is determined.

In the above embodiment, the description has been made assuming that the droplets ejected from the recording head are ink, and that the liquid stored in the ink tank is ink. It is not limited. For example, an ink tank may contain a processing liquid discharged to a recording medium in order to improve the fixability and water resistance of the recorded image or to improve the image quality.

The above-described embodiment is provided with a means (for example, an electrothermal converter such as a heater, a laser beam, or the like) for generating thermal energy as energy used for performing ink ejection, particularly in an ink jet recording system. The present invention achieves high-density and high-definition recording by using a method in which a change in the state of ink is caused by the thermal energy.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method can be applied to both the so-called on-demand type and continuous type. In particular, in the case of the on-demand type, liquid (ink)
By applying at least one drive signal corresponding to the recorded information and providing a rapid temperature rise exceeding the film boiling to the electrothermal transducer arranged corresponding to the sheet or the liquid path holding the Since thermal energy is generated in the electrothermal transducer and film boiling occurs on the heat-acting surface of the recording head, bubbles in the liquid (ink) corresponding to this drive signal on a one-to-one basis can be formed. It is valid.

By discharging the liquid (ink) through the discharge opening by the growth and contraction of the bubble, at least one droplet is formed. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable.

As the pulse-shaped drive signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. Further, if the conditions described in US Pat. No. 4,313,124 relating to the temperature rise rate of the heat acting surface are adopted, more excellent recording can be performed.

The configuration of the recording head is not limited to the combination of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in the above-mentioned respective specifications. A configuration using U.S. Pat. No. 4,558,333 or U.S. Pat. No. 4,459,600, which discloses a configuration in which a heat acting surface is arranged in a bent region, is also included in the present invention. In addition, for multiple electrothermal transducers,
JP-A-59-123670 which discloses a configuration in which a common slot is used as a discharge part of an electrothermal transducer, and JP-A-59-123670 which discloses a configuration in which an opening for absorbing a pressure wave of thermal energy corresponds to a discharge part. A configuration based on 138461 may be adopted.

Further, as a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the recording apparatus, the length is determined by combining a plurality of recording heads as disclosed in the above-mentioned specification. This may be either a configuration satisfying the above requirements or a configuration as a single recording head formed integrally.

In addition to the cartridge type recording head in which the ink tank is provided integrally with the recording head itself described in the above embodiment, the recording head is electrically connected to the apparatus main body by being mounted on the apparatus main body. A replaceable chip-type recording head, which enables a simple connection and supply of ink from the apparatus main body, may be used.

It is preferable to add recovery means for the print head, preliminary auxiliary means, and the like to the configuration of the printing apparatus described above, since the printing operation can be further stabilized. Specific examples thereof include capping means for the recording head, cleaning means, pressurizing or suction means, preheating means using an electrothermal transducer or another heating element or a combination thereof. It is also effective to provide a preliminary ejection mode for performing ejection that is different from printing, in order to perform stable printing.

Further, the recording mode of the recording apparatus is not limited to the recording mode of only the mainstream color such as black, and may be a single recording head or a combination of plural recording heads. Alternatively, the apparatus may be provided with at least one of full colors by color mixture.

In the embodiments described above, the description is made on the assumption that the ink is a liquid. However, even if the ink solidifies at room temperature or lower, it is possible to use an ink that softens or liquefies at room temperature. Or, in the ink jet method, generally, the temperature of the ink itself is controlled within a range of 30 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in a stable ejection range.
It is sufficient that the ink is in a liquid state when the use recording signal is applied.

In addition, in order to positively prevent the temperature rise due to thermal energy as energy for changing the state of the ink from a solid state to a liquid state, the temperature is positively prevented.
Alternatively, in order to prevent evaporation of the ink, an ink which solidifies in a standing state and liquefies by heating may be used. In any case, the application of heat energy causes the ink to be liquefied by application of the heat energy according to the recording signal and the liquid ink to be ejected, or to start to solidify when reaching the recording medium. The present invention is also applicable to a case where an ink having a property of liquefying for the first time is used.

In such a case, the ink is disclosed in JP-A-54-5
No. 6,847, or Japanese Patent Application Laid-Open No. 60-71260, in which the porous sheet is opposed to the electrothermal converter while being held as a liquid or solid substance in the concave portion or through hole of the porous sheet. It may be. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

The present invention can be applied to a system including a plurality of devices (for example, a host computer, an interface device, a reader, a printer, and the like), and can be applied to a single device (for example, a copier, a facsimile) Device).

Further, an object of the present invention is to supply a storage medium (or a recording medium) storing a program code of software for realizing the functions of the above-described embodiments to a system or an apparatus, and to provide a computer (a computer) of the system or the apparatus. It is needless to say that the present invention can also be achieved by a CPU or an MPU) reading and executing the program code stored in the storage medium. In this case, the program code itself read from the storage medium implements the functions of the above-described embodiment, and the storage medium storing the program code constitutes the present invention.

The functions of the above-described embodiments are implemented when the computer executes the readout program codes, and the operating system (OS) running on the computer is executed based on the instructions of the program codes. ) May perform some or all of the actual processing, and the processing may realize the functions of the above-described embodiments.

Further, after the program code read from the storage medium is written into the memory provided in the function expansion card inserted into the computer or the function expansion unit connected to the computer, the program code is read based on the instruction of the program code. Needless to say, the CPU included in the function expansion card or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

When the present invention is applied to the storage medium, the storage medium stores program codes corresponding to the above-described flowcharts and timing charts (shown in FIG. 10 and / or FIGS. 5, 7, and 8). Will be done.

[0108]

As described above, according to the present invention, the rise in the temperature of the print head before and after printing can be monitored successively. To quickly and accurately detect and prevent unnecessary recording by wasting the recording medium and recording time, and also reduce the damage to the recording head and extend the life of the recording head. There is an effect that it becomes possible.

[Brief description of the drawings]

FIG. 1 is an external perspective view illustrating an outline of a configuration of a recording apparatus to which the present invention is applied.

FIG. 2 is a block diagram illustrating a control configuration of the printing apparatus of FIG. 1;

FIG. 3 is a detailed block diagram of a head temperature detection circuit in the block diagram shown in FIG. 2;

FIG. 4 is a circuit diagram showing a specific example of the head temperature detection circuit of FIG. 3;

FIG. 5 is a timing chart showing changes in signals of various parts of the head temperature detection circuit of FIG. 4;

FIG. 6 is a circuit diagram showing a first modification of the head temperature detection circuit of FIG. 3;

FIG. 7 is a timing chart showing a change in a signal of each section of the head temperature detection circuit of FIG. 6;

FIG. 8 is a timing chart showing changes in signals of respective units in a second modification of the head temperature detection circuit.

FIG. 9 is an external view illustrating a configuration example of a recording head.

FIG. 10 is a flowchart illustrating a process of a head temperature detection circuit in FIG. 3;

[Explanation of symbols]

 Reference Signs List 11 CPU 14 Head drive control circuit 15 Recording head 1502 Temperature detector 16 Head temperature detector 1600 Temperature detector control circuit 1601 Sample / hold circuit 1602 Comparison judgment circuit

Claims (14)

[Claims] 1. An ink jet recording apparatus which performs recording by a recording head which discharges ink by using thermal energy, comprising: a temperature measuring means for obtaining data relating to a temperature of the recording head; First temperature data is obtained, and after performing the recording, second temperature data is obtained,
Measurement control means for controlling the temperature measurement means, difference means for obtaining a difference between the first and second temperature data, and comparing the difference with a predetermined value, wherein the difference is larger than the predetermined value An ink jet recording apparatus comprising: a determination unit configured to determine that an ink ejection failure has occurred in the recording head. 2. The ink jet recording apparatus according to claim 1, wherein said determination means includes a notification means for generating a specific signal when it is determined that an ink ejection failure has occurred. 3. The printing apparatus according to claim 1, further comprising a recovery unit that performs a recovery process of the recording head when the determination unit determines that an ink discharge failure has occurred.
Or the inkjet recording device according to 2. 4. The recording head according to claim 1, wherein the recording head is divided into a plurality of blocks and driven, and the recording in the predetermined unit is recording performed by one block. 4. The ink jet recording apparatus according to any one of claims 1 to 3. 5. The inkjet according to claim 1, wherein the printing in the predetermined unit is performed by driving each printing element of the print head once. Recording device. 6. The ink jet recording apparatus according to claim 1, further comprising a holding unit for holding the first and second temperature data. 7. The ink jet recording apparatus according to claim 6, wherein said holding means is a sample and hold circuit including a capacitor and a gate. 8. The apparatus according to claim 1, wherein said temperature measuring means includes a semiconductor element, and obtains said temperature data by utilizing a fact that a resistance value of said semiconductor element changes according to an ambient temperature. The inkjet recording device according to any one of the above. 9. An ink jet recording apparatus according to claim 8, wherein said semiconductor element is a diode. 10. A method of detecting an ejection failure of an ink jet recording apparatus which performs recording by a recording head which discharges ink by using thermal energy, wherein a first temperature related to the temperature of the recording head before performing recording in a predetermined unit. A first temperature measurement step for obtaining temperature data; a second temperature measurement step for obtaining second temperature data relating to the temperature of the print head after performing the recording; and a difference between the first and second temperature data. An inkjet printing apparatus comprising: a difference step; and a determining step of comparing the difference with a predetermined value and determining that an ink ejection failure has occurred in the print head when the difference is greater than the predetermined value. Ejection failure detection method. 11. The ejection failure of the ink jet recording apparatus according to claim 10, wherein the determination step includes a notification step of generating a specific signal when it is determined that an ink ejection failure has occurred. Detection method. 12. The print head according to claim 10, further comprising a recovery step of performing a print head discharge recovery process when it is determined in the determination step that an ink discharge failure has occurred. Ink ejection failure detection method for an ink jet recording apparatus. 13. The recording head according to claim 10, wherein the recording head is divided into a plurality of blocks and driven, and the recording in the predetermined unit is recording performed by one block. 13. The ejection failure detection method for an ink jet recording apparatus according to any one of items 1 to 12. 14. The ink-jet apparatus according to claim 10, wherein the printing in the predetermined unit is performed by driving each printing element of the print head once. An ejection failure detection method for a printing apparatus.