JPH1034971A - Mechanism for detecting ink in liquid chamber of ink jet recorder and ink jet recorder mounting that mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To shorten the detecting time while lessening burden of the space or the cost on a recording head or a printer body by arranging a plurality of ink detection electrodes on the heater board in a liquid chamber of a mechanism for detecting ink in the liquid chamber. SOLUTION: Ink from an ink supply tube 2 is passed on the bottom face of a liquid chamber 1, i.e., a heater board 4, and fed to a nozzle 3. The ink is then heated and blown by feeding a current to a heating element 6 located at the forward end of the heater board 4. Consequently, pressure in the nozzle 3 is varied and an ink droplet is jetted thus making a record on a recording medium. Ink detection electrodes 8a, 8b are formed on the surface of the heater board 4 along with a circuit for driving the heating element 6. From the viewpoint of deterioration of the electrodes 8a, 8b and chemical change of the ink, a detection voltage is preferably applied only when the ink in the liquid chamber 1 is detected and the electrodes are discharged after detecting the ink.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mechanism for detecting the presence or absence of ink in a liquid chamber of an ink jet recording apparatus which supplies ink from an ink tank to a recording head and discharges ink from a nozzle at the tip of the recording head to perform recording. The present invention relates to an inkjet recording apparatus having a mechanism.

[0002]

2. Description of the Related Art The presence or absence of ink in a liquid chamber of a recording head of an ink jet recording apparatus is a problem related to whether or not recording is possible. Conventionally, the remaining amount of ink in the ink tank is detected,
Although a method of warning the lack of ink is known, since this method does not directly detect the presence or absence of ink in the liquid chamber, it cannot be confirmed whether or not ink has actually run out in the liquid chamber.

As means for directly detecting the presence or absence of ink in the liquid chamber, for example, a thermal ink jet recording apparatus is used to record abnormal temperature rise in the liquid chamber due to heat generated by a heater when there is no ink in the liquid chamber. A technique of detecting by a temperature measuring element provided on a heater board substrate of a head (Japanese Patent Laid-Open No. 5-293968), and a light emitting / receiving element provided in a liquid chamber, and light from the light emitting element to the light receiving element depending on the presence or absence of ink. (JP-A-7-232440) and a method of providing a pin-shaped electrode in a liquid chamber and judging from a change in resistance between the electrodes (JP-A-55-73562). A method is known in which an actually ejected ink droplet is detected by an optical sensor, and the presence or absence of ink in the liquid chamber of the recording head is determined based on whether or not ink has been ejected.

[0004]

However, in the above-described method of detecting an abnormal rise in temperature during idle heating, it is necessary to perform a discharge operation in order to raise the temperature of the recording head during detection, which takes a long time for detection. There is. Further, a lot of heating time is required to raise the temperature of the liquid chamber, and when there is ink in the liquid chamber, wasteful ink consumption is caused,
As a result, the running cost of the device itself is adversely affected.

In the conventional method of forming an optical sensor or a pin-shaped electrode in a liquid chamber, the number of manufacturing steps of a recording head is increased, resulting in an increase in cost. In particular, such a high cost is a serious problem in a machine of a recording head exchange type. Further, in the optical sensor system, optical characteristics greatly differ depending on the color of ink, which hinders detection.

The method of detecting the ejected ink droplets with an optical sensor requires a space for the detection sensor in the printer main body, and causes a problem that the cost and size of the printer main body increase. Further, the recording head must be moved to a predetermined position for detection, and the ejection operation must be further performed, which takes time, and causes a substantial reduction in printing speed.

An object of the present invention is to minimize the space and cost burden on the recording head or printer main body,
Provided is a liquid chamber ink presence / absence detection mechanism capable of directly and accurately detecting the presence / absence of ink in a liquid chamber, which has a short detection time, consumes little ink for detection, and an ink jet recording apparatus equipped with the same mechanism. It is to be.

[0008]

According to the present invention, there is provided a mechanism for detecting the presence or absence of ink in a liquid chamber, which has at least two or more electrodes for detecting the presence or absence of ink on a heater board substrate which is a bottom surface of the liquid chamber.

The ink presence / absence detection mechanism of the present invention may be formed on a heater board substrate, and has an ink-resistant and conductive ink corrosion-resistant layer and an ink presence / absence detection surface on the heater board substrate. The electrodes may be separately formed to form a thin film, and a thin film having electrical insulation may be formed on the surface of the ink corrosion-resistant layer. The material of the ink corrosion-resistant layer and the electrode for detecting the presence or absence of ink is Ta, The material of the electrically insulating thin film may be Ta oxide, and each of the liquid chambers may have a pair of the electrodes for detecting the presence or absence of the ink. May be connected in series, and the connection of the ink presence / absence detection electrode between adjacent liquid chambers may be performed by the same material member as the ink presence / absence detection electrode. , Except when the detection of the ink presence may be those in a discharged state with each other, ink presence detection power applied between the ink presence detection electrodes may be one which is an AC power source.

The ink jet recording apparatus of the present invention is equipped with the above-described ink presence / absence detecting mechanism of the present invention.

When the ink jet recording apparatus of the present invention detects that there is no ink in at least one of the liquid chambers, it displays at least one of a warning display, a stop of a recording operation, and a head ejection stabilizing operation. Control means for performing the detection of the presence or absence of the ink in at least one or more liquid chambers during the printing operation. When it is detected that there is no ink, a control means for displaying a warning, stabilizing the ejection of the head, and detecting the presence or absence of ink in the liquid chamber again may be mounted.

[0012]

Embodiments of the present invention will now be described with reference to the drawings.

(First Embodiment) FIGS. 1 to 4 are explanatory views of a first embodiment of the present invention. FIG. 1 schematically shows the structure of the liquid chamber 1 in the recording head. The ink is supplied from the ink supply pipe 2 to the heater board substrate 4 serving as the bottom of the liquid chamber 1.
It passes above and is supplied to the nozzle 3. Heater board substrate 4
The ink is heated and foamed by passing an electric current through the heating resistor 6 at the tip of the nozzle, and the pressure inside the nozzle 3 changes due to this foaming phenomenon, thereby ejecting ink droplets and recording on a recording medium. Electrode 8 for ink detection on the surface of heater board substrate 4
a, 8b are formed, and a circuit (not shown) for driving the heating resistor 6 is formed.

FIG. 2 shows a cross section of the heater board substrate 4 before the electrodes are formed. 9 is a silicon substrate, 10 is S
An insulating layer such as iO _2, a heating resistor 12 such as Ta ₂ N, and a wiring 13 for supplying a current to the heating resistor are generally made of Al. Reference numeral 14 denotes an insulating / protective layer made of SiO ₂ or the like, and reference numeral 5 denotes an electrode layer for detecting ink.

The material of the electrode layer is not particularly limited as long as it has electrical conductivity. However, a metal having high corrosion resistance to ink is more preferable because the detection stability and reliability are high. Au and the like. Further, in this embodiment, the insulating / protecting layer 14 has a single-layer structure, but is not limited to this. If the insulating / protecting layer 14 plays a role of insulation / protection (resistance to ink corrosion and resistance to cavitation) by a plurality of layer structures. Often, the insulating protective layer 14 under the electrode layer 5 must have excellent electrical insulation.

In general, a thin film forming and processing technique is used for forming the heater board substrate 4. The ink detection electrodes 8a,
The electrode layer 5 for forming the electrode 8b can be formed simultaneously with another film of the heater board substrate 4 during this film forming process, which is a problem in the conventional ink presence / absence detection method using detection electrodes. Further, the manufacturing and assembling process of the head for forming the pin-shaped ink presence / absence detection electrode in the liquid chamber can be simplified, the productivity can be improved, and the cost of the head can be prevented. Further, since the ink detection electrodes 8a and 8b are formed by patterning the electrode layer 5 by photolithography and performing etching, the ink detection electrodes 8a and 8b have a degree of freedom in place and size on the heater board substrate in the liquid chamber. It is possible to design according to the overall structure of the above. Portions other than the electrodes are etched, exposing the insulating / protective layer 14. The number of electrodes is at least two, but is not particularly limited. In this example, a case of one detection circuit including two electrodes is shown. Next, actual detection will be described with reference to FIGS. FIG. 3 is a plan view of the heater board substrate 4 and the PCB 20 of the present embodiment. FIG. 4 is a cross-sectional view of a side surface of the head, and an ink tank 7 is shown in the vicinity.

In FIG. 4, a signal for driving the head and a signal for detecting the presence or absence of ink are input to the head terminal 19 from the printer main body. The ink flows from the ink tank 7 into the liquid chamber 1 through the liquid chamber flow path 2 sandwiched between the top plates 15.
In FIG. 3, a voltage is applied between the electrodes 8a and 8b from a power supply (not shown) via the ink detection terminals 19a and 19b of the head, the wiring in the PCB 20, and the bonding wires 11a and 11b. At this time, the terminal 19
By measuring the current flowing between a and 19b with the detection circuit of the printer body, the resistance value between the electrodes can be known. When ink is present in the liquid chamber 1, a current flows between the electrodes via the ink. On the other hand, when there is no ink in the liquid chamber 1, an air layer is formed between the electrodes, and the resistance between the electrodes increases. Will not flow. That is, when there is ink in the liquid chamber 1, the detection current is large, and when there is no ink in the liquid chamber, the detection current is small. After AD conversion of the detected current value, the CPU in the ink jet recording apparatus determines whether the detected current value is equal to or larger than a predetermined threshold value, and the presence or absence of ink in the liquid chamber 1 can be known. The time required for detection is sufficient if the current flows through the ink.
There is no need for a long time for detection as in the conventional abnormal temperature rise detection method in the liquid chamber, and no time for moving the recording head to a predetermined position for detection as in the conventional ink droplet optical detection method. Therefore, the detection can be performed without substantially lowering the substantial printing speed. Further, the printer main body only needs to have a circuit for electrically determining the presence or absence of ink, so that space and cost burden on the main body can be minimized.

Here, from the viewpoint of deterioration of the electrodes and chemical change of the ink, it is desirable to apply a detection voltage only when detecting the presence or absence of ink in the liquid chamber, and to perform discharge between the electrodes after the detection.

Although the positions of the electrodes 8a and 8b in the liquid chamber are not particularly defined, they need to be electrically isolated from other parts for accurate detection. Furthermore, it is more preferable that they are far apart from each other because they are less susceptible to the influence of capacitance.

Usually, the recording head has capping means for preventing sticking of nozzles when recording data is not input. When the recording data is input, recording is performed in a certain direction of the recording medium. At the start of recording, the presence or absence of ink is detected. If it is determined that there is no ink, the recording head is made to stand by at the capping position, and an ink error is displayed by a method such as a display. As a result, the user is informed that there is no ink, and the recording operation is stopped. If it is determined that there is ink, a normal printing operation is performed. Alternatively, when there is no ink, an automatic recovery operation may be performed to form a sequence for filling the nozzles and the liquid chamber with ink.

During recording, a detection operation is periodically performed at a certain timing. If it is determined that there is no ink, the print head is returned to the capping position, and a user is notified of an ink error in the same manner as described above. If it is determined that there is ink, the normal printing operation is continued.

By these operations, the recording head is prevented from being destroyed and the recording data is lost, and the reliability of the ink jet recording apparatus can be improved.

(Second Embodiment) Regarding the second embodiment,
This will be described with reference to FIG.

In the above-described first embodiment, the case where the insulating / protective layer 14 serving as the upper surface layer of the heater board substrate is composed of only one layer made of a single material has been described. Some have improved the reliability of each function. For example, as shown in FIG. 5A), an insulating material such as SiO ₂ and SiN is used for the insulating layer 14a as the first layer.
As the second layer, there is a layer in which a metal such as Ta having high alkali resistance and high ductility is used as the second layer as a protective layer against stress deterioration due to ink corrosion and cavitation. When the protective layer 16 is made of a material having conductivity as described above, even if an electrode is formed directly on the protective layer, a wetting current is generated in the protective layer and stable detection cannot be performed.

Therefore, as shown in FIG. 5B), by inserting a second insulating layer 17 between the protective layer 16 and the detection electrode 8, wetting current can be prevented, and stable detection can be obtained.

In this embodiment, the protective layer is made of metal such as Ta. However, the present invention is not limited to this.
Any material that satisfies the role of the protective layer may be used. Further, the protective layer 16 shows the case where the ink corrosion-resistant layer also serves as the cavitation-resistant layer. However, the present invention is not limited to this, and a plurality of layers having different functions may be provided.

(Third Embodiment) Another embodiment in which the protective layer 16 shown in FIG. 5A is made of a material having conductivity such as a metal as shown in FIG. Will be explained.

After forming the conductive protective layer 16 of the heater board substrate shown in FIG. 5A), the conductive protective layer 16 is formed by patterning by photolithography, the electrode forming portion is etched to the protective layer 14a, and the electrode 8 separated from the protective layer 16 is removed. It is formed on the protective layer 14a. (In a conventional heater board substrate manufacturing process, there is a process of partially etching the protective layer 16 in order to connect a bonding wire to a wiring for flowing a current to the heating resistor. This can be performed only by changing the pattern of the lithography mask, and can be performed without adding an additional process.) Further, an insulating film 18 is formed on the surface of the protective layer 16. The role of the insulating film 18 is to prevent current from leaking from the ink in the liquid chamber 1 to the protective layer 16 to prevent the detection sensitivity from deteriorating and becoming unstable.

As described above, in the present embodiment, the protective layer 16 is etched, separated into the protective layer 16 and the electrode 8, and the protective layer 1 is removed.
6 is covered with the insulating layer 18 to prevent a wetting current and to achieve stable detection. Further, compared to the second embodiment, the detection electrode is formed without the need for the step of forming the protective layer 17 for the electrode. it can.

However, when the electrode 16 is formed by etching 16, the portion between the protective layer 16 and the electrode 8 is etched with an ink-resistant material. Al wiring 1 for
3 may be corroded, thereby lowering the reliability of ink ejection. Therefore, the position of the electrode was
It must be arranged at a position where there is no wiring 13.

Although the protective layer 16 is made of metal such as Ta in the present embodiment, the material is not particularly limited, and any material having conductivity and satisfying the role of the protective layer may be used. Further, the protective layer 16 shows the case where the ink corrosion-resistant layer also serves as the cavitation-resistant layer. However, the present invention is not limited to this, and a plurality of layers having different functions may be provided.

(Fourth Embodiment) In the third embodiment, it is necessary to form an insulating film 18 on the protective layer 16 after etching for forming electrodes, and a pattern is formed by photolithography for forming detection electrodes. After etching,
The insulating film 18 is formed by performing the vacuum deposition process again. As shown in the third embodiment, the pattern formation of the electrode itself does not increase the number of steps, but the manufacturing process becomes somewhat complicated due to the subsequent formation of the insulating film. Thus, in this embodiment, the insulating film 18 is not deposited and the insulating film 18 is not deposited.
The method for forming the will be described.

In the cross section of the heater board substrate shown in FIG. 6, as shown in the second and third embodiments, the protective layer 1
6. Ta is used as the material of the detection electrode 8, and the process of forming a vacuum on the heater board substrate is performed up to the separation formation of the detection electrode 8, and the insulating film 18 is not formed on the protective layer 16. Here, when electrolysis is performed using Ta as an anode,
Ta ₂ O ₅ is deposited as an anodic oxide film on the surface, and exhibits insulating properties.

For example, as one of the manufacturing methods, there is a method using a heater board whose plan view is shown in FIG. After the formation of the detection electrodes 8a and 8b, a top plate (not shown) is assembled to form a liquid chamber. Thereafter, the liquid chamber is filled with an electrolytic solution. Reference numeral 21 denotes an anodic oxide film forming wiring for applying a voltage to use the protective layer 16 as an anode. Through a wiring 21 from a power source (not shown), electrolysis is performed using the protective film 16 made of Ta as an anode and an electrode (not shown) provided in an electrolyte as a cathode.
An insulating film 18 of Ta ₂ O ₅ is formed thereon. The insulating film 18 formed in this manner can be formed only in a portion that comes into contact with the ink in the liquid chamber, and it is not necessary to perform pattern etching for leaving only a necessary portion after forming the insulating film, as in the case of vacuum deposition. There is an advantage that the manufacturing process can be prevented from becoming complicated, and the insulating film 18 can be formed only in a naturally necessary part.

Although the insulating property of the insulating film 18 is greatly affected by the magnitude and time of the applied voltage in the electrolysis, in the experiment by the inventor, sufficient insulating property for the detection experiment was obtained at an applied voltage of 35 V and an applied time of 90 sec. Was. By further increasing the applied voltage and time, a more stable insulating film can be obtained. These oxidation conditions vary greatly depending on the film configuration of the heater board substrate, the electrolytic solution, the wiring resistance, and the like, and the values listed here are merely examples.

Here, a printing ink commonly used as an electrolytic solution was used. In the final stage of the normal head manufacturing process, ink is injected after completion to perform a printing test.
Since the ink is a kind of electrolyte that shows alkaline, if the ink in this step is used for forming an anodic oxide film, the trouble of injecting the electrolyte into the liquid chamber is omitted, and the productivity is further improved. Can be. At this time, the electrolysis of the ink exerts some influence on the heater board substrate, and there is a possibility that the print quality may be deteriorated. However, in the experiment by the inventor, no particularly significant effect was observed.

As described above, the anodic oxide film is formed by electrolysis after the electrodes are formed, and the insulating property is obtained. Thus, the vapor deposition step for forming the insulating film can be omitted, and the productivity can be improved.

(Fifth Embodiment) In each of the above-described embodiments, the case where only one liquid chamber is provided in the recording head has been described. However, a recording head having a plurality of separated liquid chambers within one recording head. And are usually used in a color ink jet recording apparatus. FIG. 8 shows a plan view of the heater board substrate of the present embodiment. In such a recording head, inks of different colors are supplied into each liquid chamber. In this embodiment, the case of a recording head having three liquid chambers on the same heater board substrate for three color inks (yellow, magenta, and cyan) is shown. The color, type, and number of liquid chambers of the ink are not particularly limited.

801 a and 801 b are electrodes for detecting the presence or absence of ink in the liquid chamber 101, 802 a and 802 b are electrodes for detecting the presence or absence of ink in the liquid chamber 102, and 803 a and 803 b are liquid chambers 1
Reference numeral 03 denotes an electrode for detecting the presence or absence of ink, and a pair of electrodes is provided in each liquid chamber. 1101a and 1101b are bonding wires for applying a voltage to the ink presence / absence detection electrodes 801a and 801b, respectively. Similarly 11
02a and 1102b are ink presence / absence detection electrodes 802a and
Reference numeral 802b denotes bonding wires 1103a and 1103b for applying a voltage to the electrodes 803a and 803b for detecting the presence or absence of ink. By applying a voltage from a power source (not shown) to the ink detecting electrodes in each liquid chamber, the presence or absence of ink in each liquid chamber is detected, and it is possible to determine which liquid chamber has no ink.

(Sixth Embodiment) In the fifth embodiment, which of the plurality of liquid chambers contains no ink is detected and the user is notified. In a head having a liquid chamber, the suction recovery operation is often performed for each head. Therefore, when the ink in at least one of the liquid chambers runs out and the suction recovery operation is performed, all of the liquid chambers in the head are sucked. It should be understood that there is no particular need to limit which liquid chamber is out of ink. Therefore, a method of connecting the wirings from the respective liquid chambers in series in the fifth embodiment outside the head can be considered, but this method increases the number of wirings more than necessary and increases the cost.

Another embodiment will be described. FIG. 9 shows a plan view of the heater board substrate. Electrode layer 5
Is formed between the liquid chambers 101 and 102 as shown in the electrode region 20a in the figure. Portions 801b and 802a located in the liquid chamber of the electrode region 20a serve as electrodes for detecting the presence or absence of ink in the liquid chambers 101 and 102, respectively.
The portion outside the liquid chamber plays a role of wiring for electrically connecting the electrodes. Similarly, the electrode region 20 is also provided between the liquid chambers 102 and 103.
A pattern is formed as shown in FIG.
3a is connected in series.

By applying a voltage between the bonding wires 1101a and 1103b connected to the ink presence / absence detecting electrodes 801a and 803b at both ends of the liquid chambers 101 and 103, a current flows in series between the liquid chambers. . If there is no ink in at least one of the liquid chambers 101 to 103, the value of the flowing current decreases.

When it is detected that there is no ink in at least one liquid chamber, an ink error display is performed or a recovery operation of the entire head is performed. With such an operation, the reliability of the printer itself can be improved.

With the above arrangement, there is no need to provide any wiring outside the heater board substrate to connect the ink presence / absence detection electrodes of each liquid chamber, and the wiring between the liquid chambers is formed by the ink detection electrodes. Therefore, the number of steps can be reduced, the productivity can be improved, and the cost can be prevented from increasing.

(Seventh Embodiment) In the first embodiment, when there is no ink in the liquid chamber, recording is not performed, capping is performed, and an ink error is displayed. But,
After that, the user has to perform some kind of recovery suction operation or tank replacement. Therefore, when the absence of ink is detected, a predetermined suction recovery is automatically performed by the apparatus main body. After the suction recovery, the presence / absence of ink is detected again. When the absence of ink is detected again, an ink error is displayed and printing is stopped. In other cases, printing is restarted.

By these operations, the reliability and operability of the printer main body can be improved.

(Eighth Embodiment) In an ink jet recording apparatus, there is usually no ink in the liquid chamber when there is no ink in the liquid chamber and when there is ink in the ink tank. It is conceivable that there is no ink in the first embodiment, but this determination cannot be made in the first embodiment. Therefore, if the presence or absence of ink is detected by detecting the presence or absence of ink in the liquid chamber, a predetermined suction recovery operation is performed once or a plurality of times, and then the presence or absence of ink is detected again. At this time, when the absence of ink is detected again, it can be determined that there is no ink in the ink tank. That is, by combining the ink presence / absence detection and the recovery operation, the remaining amount of ink in the ink tank can be detected, and the usability as an ink jet recording apparatus can be improved.

(Ninth Embodiment) In the above embodiment,
Current flows from the electrode to the ink for ink detection,
Not a small amount of electrolysis occurs on the electrode surface, which may cause deterioration of the ink detection electrode. The detection current changes due to the deterioration of the ink detection electrode, which causes unstable detection. Here, depending on the material of the electrode, the ink and the electrolysis may be a reversible reaction. Thus, when an AC voltage is applied to the electrode for ink detection, the polarity of the electrode at the time of electrolysis changes, thereby causing a chemical reaction opposite to the previous reaction and preventing the electrode from deteriorating. By applying an AC voltage to the electrodes in this manner, electrode deterioration can be prevented, and detection reliability can be increased.

(Embodiment 10) In each of the embodiments described above, the presence or absence of ink is detected by measuring the electrical resistance between both electrodes. However, the present invention is not limited to the above example, and there is a method of measuring the capacitance between both electrodes with a similar configuration.

For example, referring to FIG.
The capacitance between 9a and 19b greatly differs depending on the presence or absence of ink. The capacitance between the electrodes is large when there is ink, and small when there is no ink. Therefore, the detection circuit 17
20 is changed to a circuit for measuring the electric resistance between both electrodes,
If a circuit for measuring the capacitance between both electrodes is used, the presence or absence of ink between the electrodes can be detected by measuring the capacitance between the electrodes.

(Supplementary Example) An example of an ink jet printer embodying the present invention will be described below.

<Schematic Description of Apparatus Main Body> FIG. 10 shows an ink jet printer I according to a representative embodiment of the present invention.
It is an external appearance perspective view which shows the outline of a structure of JRA. In FIG. 10, the carriage HC that engages with the spiral groove 5004 of the lead screw 5005 that rotates via the driving force transmission gears 5011 and 5009 in conjunction with the forward and reverse rotation of the drive motor 5013 has pins (not shown). Then, it is reciprocated in the directions of arrows a and b. An ink jet cartridge IJC is mounted on the carriage HC. 500
Reference numeral 2 denotes a paper pressing plate, which presses the paper against the platen 5000 in the moving direction of the carriage. 5007, 50
Reference numeral 08 denotes a home position detecting means for confirming the presence of the carriage lever 5006 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. Reference numeral 5015 denotes suction means for sucking the inside of the cap.
, The suction recovery of the recording head is performed. Reference numeral 5017 denotes a cleaning blade. Reference numeral 5019 denotes a member which 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 5012 denotes a lever for starting suction for suction recovery.
It moves with the movement of 20, and the driving force from the drive motor is controlled by known transmission means such as clutch switching.

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 a timing, any of the examples can be applied.

<Description of Control Structure> Next, a control structure for executing the recording control of the above-described apparatus will be described.

FIG. 11 shows an ink jet printer IJRA.
FIG. 3 is a block diagram showing a configuration of a control circuit of FIG. In the figure showing a control circuit, 1700 is an interface for inputting a recording signal, 1701 is an MPU, 1702 is an MPU 17
01 for storing a control program to be executed by the program 01
An OM 1703 is a dynamic RAM for storing various data (such as the print signal and print data supplied to the head). A gate array 1704 controls supply of print data to the print head 1708.
Interface 1700, MPU 1701, RAM 17
Also, data transfer control during 03 is performed. Reference numeral 1710 denotes a carrier motor for transporting the recording head 1708, and reference numeral 1709 denotes a transport motor for transporting the recording paper. Reference numeral 1705 denotes a head driver for driving the head, and reference numerals 1706 and 1707 denote motor drivers for driving the transport motor 1709 and the carrier motor 1710, respectively.

Reference numeral 1720 denotes a detection circuit for detecting the presence or absence of ink in the recording head, which will be described in detail later. Details of the operation of this detection circuit will be described later.

The operation of the above control configuration will be described. When a recording signal enters the interface 1700, the gate array 17
04 and the MPU 1701 converts the recording signal into recording data for printing. Then, the motor driver 17
06 and 1707 are driven, and the head driver 1
The recording head is driven according to the recording data sent to 705, and printing is performed.

The present invention includes a means (for example, an electrothermal converter or a laser beam) for generating thermal energy as energy used for performing ink ejection, particularly in an ink jet recording system. The printing apparatus of the type that causes a change in the state of the ink has been described.
Higher detail can be achieved.

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 that gives a rapid temperature rise exceeding the film boiling corresponding to the recorded information, to the electrothermal transducer disposed corresponding to the sheet or liquid path in which This is effective because heat energy is generated in the electrothermal transducer, causing film boiling on the heat-acting surface of the recording head, and as a result, bubbles in the liquid (ink) corresponding to this drive signal on a one-to-one basis can be formed. It is. The liquid (ink) flows through the ejection opening due to the growth and contraction of this bubble.
To form at least one droplet. When this drive signal is formed into a pulse shape, the growth and shrinkage of the bubbles are immediately and appropriately performed, so that the liquid (ink) having particularly excellent responsiveness is obtained.
Discharge can be achieved, which is more preferable.

As the pulse-shaped driving signal, those described in US Pat. Nos. 4,463,359 and 4,345,262 are suitable. In addition,
US Patent No. 4 of the invention relating to the rate of temperature rise of the heat acting surface
If the conditions described in the specification of Japanese Patent No. 313124 are adopted, more excellent recording can be performed.

As the configuration of the recording head, in addition 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 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, an exchangeable chip-type recording head, which is electrically mounted to the apparatus main body and can supply ink from the apparatus main body when attached to the apparatus main body, or integrated with the recording head itself. Alternatively, a cartridge type recording head provided with an ink tank may be used.

It is preferable to add recovery means for the printhead, preliminary auxiliary means, and the like provided as components of the printing apparatus of the present invention since the effects of the present invention can be further stabilized. . If these are specifically mentioned, 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, and printing Performing a preliminary ejection mode for performing another ejection is also effective for performing 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, but 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 embodiment of the present invention described above, the ink is described as a liquid. However, an ink that solidifies at room temperature or lower, or an ink that softens or liquefies at room temperature may be used. Alternatively, in the ink jet method, the temperature of the ink itself is generally 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. May be a liquid.

In addition, in order to positively prevent the temperature rise due to thermal energy as energy for changing the state of the ink from the solid state to the liquid state, the temperature can be positively prevented.
Alternatively, in order to prevent evaporation of the ink, ink that 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, as described in JP-A-54-56847 or JP-A-60-71260, the ink is held in a liquid state or a solid state in the concave portion or through hole of the porous sheet. It is good also as a form which opposes an electrothermal transducer. In the present invention, the most effective one for each of the above-mentioned inks is to execute the above-mentioned film boiling method.

In addition to the above, the recording apparatus according to the present invention may be provided not only as an image output terminal of an information processing apparatus such as a computer but also integrally or separately, a copying apparatus combined with a reader or the like, and a transmission / reception apparatus. It may take the form of a facsimile machine having functions.

[0069]

As described above, according to the present invention, the presence or absence of the ink detection electrode formed simultaneously with the formation of the heater board substrate in the liquid chamber provided in the recording head of the ink-jet recording apparatus is improved. Can provide a low-cost ink chamber presence / absence detection mechanism that can instantaneously and accurately detect the presence / absence of ink in the ink jet recording. There is an effect that the reliability of the device can be improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a structure of a liquid chamber in a recording head.

FIG. 2 is a sectional view of a main part of a liquid chamber heater board substrate according to the first embodiment of the present invention.

FIG. 3 is a plan view of the heater board substrate of the first embodiment.

FIG. 4 is an explanatory cross-sectional view of a recording head including a liquid chamber ink presence / absence detecting mechanism of the first embodiment, as viewed from a side surface direction.

FIG. 5 is an explanatory sectional view of a heater board substrate according to a second embodiment of the present invention.

FIG. 6 is an explanatory sectional view of a heater board substrate according to a third embodiment of the present invention.

FIG. 7 is a plan view for explaining a heater board substrate according to a fourth embodiment of the present invention.

FIG. 8 is a plan view showing a main part of a recording head according to a fifth embodiment of the present invention.

FIG. 9 is a plan view illustrating a main part of a recording head according to a sixth embodiment of the present invention.

FIG. 10 is an inkjet printer I embodying the present invention.
It is an external appearance perspective view which shows the outline of a structure of JRA.

FIG. 11 is a block diagram illustrating a configuration of a control circuit of the inkjet printer IJRA.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Liquid chamber 2 Ink supply pipe 3 Nozzle 4 Heater board substrate 5 Electrode layer 6 Heating resistor 7 Ink tank 8a, 8b Ink presence / absence detection electrode 9 Si substrate 10 Insulation layer 11 Bonding wire 13 Al wiring 14 Insulation / protection layer 15 Top Plate portion 16 Protective layer 17 Insulating layer 18 Insulating film 19 Bonding wire 19, 19a, 19b Terminal 20 PCB 21 Wiring 5000 Platen 5002 Paper press plate 5004 Spiral groove 5005 Lead screw 5006, 5012 Lever 5007, 5008 Photocoupler 5009, 5011 Driving force Transmission gear 5013 Drive motor 5015 Suction means 5016 Support member 5017 Cleaning blade 5018 Body support plate 5019 Member 5020 Cam 5022 Cap member 5023 Opening in cap 1700 A Interface 1701 MPU 1702 ROM 1703 RAM 1704 a gate array 1705 a head driver 1706 and 1707 a motor driver 1708 recording head 1709 conveyance motor 1710 carrier motor 1720 detecting circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nao Yaegashi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Kenjiro Watanabe 3-30-2 Shimomaruko, Ota-ku, Tokyo Non Corporation

Claims (15)

[Claims] 1. An ink jet recording apparatus, which supplies ink from an ink tank to at least one or more liquid chambers in a recording head and discharges the ink in the liquid chambers from nozzles at the tip of the recording head to perform recording. An ink presence / absence detection mechanism for detecting presence / absence of ink in a room, wherein at least two or more ink presence / absence detection electrodes are provided on a heater board substrate in the liquid chamber, respectively. . 2. An ink supply unit supplies ink from an ink tank to at least one or more liquid chambers in a recording head, and applies a voltage to a heating resistor at a front end of a heater board substrate in each of the liquid chambers. A liquid that detects the presence or absence of ink in a liquid chamber of an ink jet recording apparatus that performs recording by discharging ink from a nozzle at the tip of a recording head by utilizing physical volume change caused by heating and foaming of ink on the body. An ink presence / absence detection mechanism in a liquid chamber, wherein at least two or more electrodes for ink presence / absence detection are provided on the heater board substrate, respectively. 3. The liquid chamber ink presence / absence detection mechanism according to claim 2, wherein the ink presence / absence detection electrode is formed as a thin film on the heater board substrate. 4. An ink-corrosion-resistant layer having ink resistance and conductivity and the ink presence / absence detection electrode are separately formed on the heater board substrate to form a thin film, and the surface of the ink-corrosion-resistant layer is electrically insulated. 3. The mechanism for detecting the presence or absence of ink in a liquid chamber according to claim 2, wherein a thin film having a property is formed. 5. The ink presence / absence detection in the liquid chamber according to claim 4, wherein the material of the ink corrosion resistant layer and the electrode for detecting the presence / absence of ink is Ta, and the material of the thin film having electrical insulation is Ta oxide. mechanism. 6. The liquid chamber ink presence / absence detection mechanism according to claim 1, further comprising a pair of the ink presence / absence detection electrodes in each of the at least one or more liquid chambers. 7. The liquid chamber ink presence / absence detection mechanism according to claim 6, wherein the ink presence / absence detection electrodes are connected in series between adjacent liquid chambers. 8. The liquid chamber ink presence / absence detection mechanism according to claim 7, wherein the connection of the ink presence / absence detection electrode between the adjacent liquid chambers is made by the same material member as the ink presence / absence detection electrode. . 9. The ink detecting device according to claim 1, wherein the electrodes for detecting the presence or absence of ink are in a mutually discharged state except when detecting the presence or absence of ink.
The ink presence / absence detection mechanism according to any one of the above items. 10. The liquid chamber ink presence / absence detection mechanism according to claim 1, wherein the ink presence / absence detection power supply applied between the ink presence / absence detection electrodes is an AC power supply. 11. The presence / absence of ink in a liquid chamber according to claim 1, wherein the presence / absence of ink is detected by measuring a capacitance between the electrodes for detecting presence / absence of ink. Detection mechanism. 12. An ink jet recording apparatus equipped with the liquid chamber ink presence / absence detection mechanism according to claim 1. 13. A control for displaying at least one or more of the liquid chambers, displaying a warning, stopping a recording operation, and performing at least one or more operations of a head ejection stabilizing operation. 13. The ink jet recording apparatus according to claim 12, comprising means. 14. An ink jet recording apparatus according to claim 12, further comprising control means for detecting the presence or absence of ink in said at least one liquid chamber during a printing operation. 15. When detecting that there is no ink in at least one of the liquid chambers, a warning is displayed, and after performing a head ejection stabilizing operation, the presence or absence of ink in the liquid chambers is detected again. The inkjet recording apparatus according to claim 12, further comprising a control unit.