JPH1034955A - Ink jet recording apparatus and ink state detecting mechanism of ink jet recording apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly reliable ink jet recording apparatus capable of reliably detecting the presence or absence of ink that can be printed out with a simple configuration and preventing recording head destruction and loss of recording data. . SOLUTION: A first detection electrode 8 disposed in a common liquid chamber 3 of an ink jet recording apparatus that discharges ink from a nozzle of a print head tip 3 into a common liquid chamber 3 for recording.
And a second detection electrode 13 disposed in the ink flow path 2 from the ink tank 6 to the common liquid chamber 3, and detects an electric resistance or a capacitance between the detection electrodes 8 and 13. And the ink state can be detected.

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 for supplying ink to a recording head from an ink tank and discharging ink from a nozzle at the tip of the recording head to a recording material to perform recording. The present invention relates to a state detection mechanism, and particularly to a mechanism for detecting the presence or absence of ink in an ink flow path and a common liquid chamber.

[0002]

2. Description of the Related Art The presence or absence of ink in a common liquid chamber of a recording head of an ink-jet recording apparatus is an important problem relating to whether or not recording is possible. Conventionally, the detection of the presence or absence of the ink has been performed by the following method.

The remaining amount of ink in the ink tank is detected,
There is a way to warn of low ink. However, with this method of detecting the remaining amount of ink in the ink tank, it is not possible to detect the presence or absence of ink in the common liquid chamber of the recording head portion, and it is not known whether or not there is actually no ink to be printed. There was a drawback that could not be dealt with in that case.

Another method is to detect the presence or absence of ink in a common liquid chamber of a recording head. For example, in a thermal ink jet recording apparatus, when there is no ink in a common liquid chamber, heat generated by a heater is used. Since abnormal temperature rise in the common liquid chamber occurs, there is a method of detecting the abnormal temperature rise by a temperature measuring element provided on the heater board substrate of the recording head (Japanese Patent Application No. 04-099).
No. 269).

There has also been proposed a method in which a light-emitting and light-receiving element is provided in a common liquid chamber, and a determination is made using the fact that the amount of light emitted from the light-emitting element reaching the light-receiving element varies depending on the presence or absence of ink.

Further, as another method, a method is known in which an actually ejected ink droplet is detected by an optical sensor to determine the presence / absence of ink and the presence / absence of ejection.

[0007]

However, in the above-described method of detecting an abnormal temperature rise during idle heat, it is necessary to raise the temperature of the recording head for detection, and for this purpose, an ejection operation must be performed. However, there is a problem that it takes time for detection. Further, a large amount of heat is required to raise the temperature of the common liquid chamber, and when there is ink in the common liquid chamber, wasteful ink consumption is caused and the running cost of the apparatus itself is adversely affected.

In the conventional method of providing an optical sensor in the common liquid chamber, the number of manufacturing steps of the printer head is increased, and the cost is increased. In particular, such a high cost is a serious problem in a machine of a printer head exchange type. Further, in the optical sensor system, the optical characteristics are greatly different depending on the color of the ink, which hinders the detection, so that a good detection cannot be performed.

Further, the method of detecting the ejected ink droplets by the 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 has to be moved to a predetermined position for detection, and the ejection operation has to be further performed, which takes time, and causes a substantial reduction in printing speed.

If the printer is left unprinted for a long period of time, bubbles may be generated in the ink flow path from the ink tank to the common liquid chamber. In such a state, even if ink is present in the common liquid chamber at the time of reprinting, ink is not supplied into the liquid chamber as soon as printing is continued.

[0011]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems, and the space and cost burdens of a recording head and a recording apparatus main body are as small as possible. It is an object of the present invention to provide a mechanism for detecting the presence / absence of ink in a state where ink consumption is small and printing can be performed accurately and easily.

The present invention has, for example, the following constitution as one means for achieving the above object.

That is, an ink state detecting mechanism of an ink jet recording apparatus for supplying ink from an ink tank into a common liquid chamber in a recording head and discharging the ink in the common liquid chamber from a nozzle at the tip of the recording head for recording. A first detection electrode disposed in at least one of the common liquid chambers and a second detection electrode disposed in an ink flow path from at least one ink tank to the common liquid chamber. And wherein the ink state between the first detection electrode and the second detection electrode can be detected.

Alternatively, there is provided an ink state detecting mechanism of an ink jet recording apparatus which supplies ink from an ink tank into a common liquid chamber in a recording head and discharges the ink in the common liquid chamber from a nozzle at the tip of the recording head to perform recording. A first detection electrode provided in at least one of the common liquid chambers, and a second detection electrode provided in at least one ink tank. The ink state between the second detection electrodes can be detected.

Alternatively, there is provided an ink state detecting mechanism of an ink jet recording apparatus which supplies ink from an ink tank into a common liquid chamber in a recording head and discharges the ink in the common liquid chamber from a nozzle at the tip of the recording head for recording. hand,
A first detection electrode disposed in at least one of the common liquid chambers; and a second detection electrode disposed in an ink flow path from at least one ink tank to the common liquid chamber and in the ink tank. And an electrode, wherein an ink state between the first detection electrode and the second detection electrode can be detected.

Further, for example, the apparatus further comprises first detecting means for detecting a resistance value between the first detecting electrode and the second detecting electrode to detect a state of ink between the quantity electrodes. And Alternatively, the first detection means detects an ink state by applying an AC voltage to the first detection electrode and the second detection electrode.

Still further, for example, the apparatus further comprises a second detecting means for detecting a capacitance between the first detection electrode and the second detection electrode and detecting a state of ink between the two electrodes. Features.

Further, for example, a heater board substrate is provided in a common liquid chamber of the ink jet recording apparatus, a heating resistor is provided on the heater board substrate, and a voltage is applied to the heating resistor. What is claimed is: 1. An ink jet recording apparatus for recording by heating an ink on said heat generating resistor to form a foam by causing the ink to foam, thereby ejecting ink droplets from a nozzle at a tip of a recording head. A thin film made of an ink-resistant material and having cavitation resistance and conductivity is formed on the uppermost layer of the substrate, and the thin film is used as a first detection electrode in the common liquid chamber. For example, a thin film formed on the uppermost layer of the heater board substrate is a Ta thin film, and the Ta thin film is a first detection electrode.

Further, for example, the second detection electrode is provided near a joint between the ink tank and the recording head. Alternatively, the second electrode has a filter function for removing dust and the like in the ink at the junction between the recording head and the ink tank.

Further, for example, the ink jet recording apparatus is
A single recording head has a plurality of common liquid chambers, and the first detection electrode in each common liquid chamber is a common electrode. Then, the first detection electrode is set to a discharge state other than when the ink state is detected, a warning is displayed when the detection means detects the absence of ink, and the ink state is detected during the printing operation, When the detecting means detects that there is no ink, the recording operation is stopped and the ejection stabilizing operation of the head is performed.

Further, for example, when the detecting means detects the absence of ink, the warning is displayed, and after the ejection stabilizing operation of the head is automatically performed, the presence or absence of ink is detected again. Features.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. Before describing the detailed mechanism, the external force of the ink jet printer of this embodiment will be described.

<Schematic Description of Apparatus Main Body> FIG. 1 shows an ink jet printer IJ which is a typical embodiment of the present invention.
It is an external appearance perspective view showing the outline of composition of RA. In FIG. 1, a carriage HC that engages with a spiral groove 5004 of a lead screw 5005 that rotates via driving force transmission gears 5011 and 5009 in conjunction with forward and reverse rotation of a 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. Reference numeral 5002 denotes a paper pressing plate, which presses the paper against the platen 5000 in the moving direction of the carriage. 5007,5008
Is a home position detecting means for confirming the presence of the carriage lever 5006 in this region and switching the rotation direction of the motor 5013.
Reference numeral 5016 denotes a member that supports a cap member 5022 that caps the front surface of the recording head. Reference numeral 5015 denotes suction means that suctions the inside of the cap, and performs suction recovery of the recording head through an opening 5023 in the cap.

Reference numeral 5017 denotes a cleaning blade.
Reference numeral 19 denotes a member which allows the blade to move in the front-rear direction, and 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. Also, 50
Reference numeral 12 denotes a lever for starting suction for recovery of suction, which moves with the movement of the cam 5020 engaging with the carriage, and the driving force from the drive motor is controlled by a known transmission means such as clutch switching or the like. .

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. 2 is a block diagram showing a configuration of a control circuit of the inkjet printer IJRA. In the figure showing a control circuit, 1700 is an interface for inputting a recording signal, 1
701, an MPU; 1702, a program ROM for storing a control program executed by the MPU 1701;
Is a dynamic RAM for storing various data (such as the recording signal and recording data supplied to the head).

Reference numeral 1704 denotes a gate array which controls supply of print data to the print head 1708, and also controls data transfer between the interface 1700, the MPU 1701, and the RAM 1703. 1710 is a recording head 170
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 discharging ink, 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.
High definition 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 corresponding to the recorded information and providing a rapid temperature rise exceeding the film boiling to an electrothermal transducer arranged corresponding to the sheet or the liquid path in which 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.

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 a combination of a plurality of recording heads as disclosed in the above specification. This may be either a configuration satisfying the above requirements or a configuration as a single recording head formed integrally.

In addition, the print head is exchangeable with a print head of a chip type, which can be electrically connected to the main body of the apparatus or supplied with ink from the main body of the apparatus, or is integrated with the print 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 recording head, preliminary auxiliary means, and the like provided as components of the recording 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 a recording mode of only a mainstream color such as black, and may be a recording head integrally formed or a combination of a plurality of 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, any ink that solidifies at room temperature or lower, or one that softens or liquefies at room temperature may be used. Alternatively, in the ink jet system, 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. It is sufficient if the ink is sometimes in a liquid state.

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,
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 thermal energy may be liquefied by the application of the thermal energy according to the recording signal, and the thermal energy may be discharged, such as the one in which the liquid ink is ejected, and the one in which the ink is already solidified when it reaches the recording medium. The present invention is also applicable to a case where an ink having a property of being liquefied for the first time by the application of an ink. In such a case, the ink is disclosed in
As described in JP-A-56847 or JP-A-60-71260, a form in which the liquid sheet or the solid 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.

In addition, as a form of the recording apparatus according to the present invention, in addition to one provided as an image output terminal of an information processing apparatus such as a computer as an integrated or separate apparatus, a copying apparatus combined with a reader or the like, It may take the form of a facsimile machine having functions.

Next, ink is supplied from the ink tank into the common liquid chamber in the recording head 1708, and the ink in the common liquid chamber is ejected from the nozzle at the leading end of the recording head. An ink state detection mechanism at the time of recording will be described.

FIGS. 3 to 6 are views for explaining an ink state detecting mechanism according to a first example of the embodiment of the present invention. FIG. 3 is a side cross-sectional view of a print head of the thermal inkjet apparatus used in this example in the configuration shown in FIG.
FIG. 4 is a plan view of the heater board substrate in the head.

3 and 4, reference numeral 1 denotes a common liquid chamber;
Denotes an ink flow path, and 3 denotes a nozzle. Reference numeral 6 denotes an ink tank, and 7 denotes a top plate for forming a common liquid chamber and a flow path. The ink is supplied from the ink tank 6 to the nozzle 3 through the ink flow path 2 and the common liquid chamber 1.

Reference numeral 4 denotes a heater board substrate, which heats and foams the ink by passing an electric current through a heating resistor 5 disposed near the tip of the nozzle 3. Due to this bubbling phenomenon, the pressure in the nozzle changes, and an ink droplet is ejected, thereby performing recording on a recording medium. Reference numeral 8 denotes a first ink detection electrode in the common liquid chamber, which is on the surface of the heater board substrate 4 and is in contact with the ink.

The first ink detecting electrode 8 also has a function of protecting the discharge heater and the # 1 wiring from physical corrosion due to ink corrosion and cavitation as a protective layer of the heater board. Further, the ink detection electrode 8 is in a state of being electrically connected to one of the terminals 12 of the head through the bonding wire 9 and the wiring 11a in the PCB 10.

Reference numeral 13 denotes a second ink detecting electrode, which is provided in the ink flow path 2. The second ink detection electrode 13 is connected to the PCB 10 via a wiring 14, and is connected to the head terminal 1 via a wiring 11 b in the PCB 10.
2 is electrically connected to one of the two.

FIG. 5 shows a heater board substrate 4 according to this embodiment.
FIG. In FIG. 5, 8 is a first ink detection electrode, 15 is a silicon substrate, 16 is an insulating material,
The first insulating layer 5 made of, for example, SiO2 or the like is a heating resistor made of, for example, Ta2N. Reference numeral 17 denotes a wiring pattern for supplying a current to the heat generating resistor 5, and generally uses $ 1 or the like.

Reference numeral 18 denotes an insulating material, for example, SiO 2 or Si 2
This is a second insulating layer made of N3 or the like.

In the present embodiment having the above-described structure, as described above, the first ink detecting electrode 8 is used as a discharge heater or the like due to corrosion of ink as a protective layer of the heater board or physical external force due to cavitation. Although the structure also has a function of protecting the l wiring, this is because the Al wiring 17 and the heating resistor 5 are protected from erosion of the ink and cavitation generated at the time of defoaming after the foaming of the ink.
Is a portion that needs to be protected. Conventionally, it is a portion that has high corrosion resistance to ink and has ductility such as metal Ta.

In the present embodiment, in order not to impair the function, a material having a sufficient role as a protective layer of the heater board such as the metal Ta as an insulating material and having electrical conductivity is used. An important feature of the embodiment is that the electrode layer made of SiO2 or Si2N3 described above can be used as an electrode for ink detection by using this portion.

As described above, when the protective layer on the heater board substrate 4 is used as the first ink detecting electrode in the liquid chamber, it is possible to form a film simultaneously with other films on the heater board substrate 4.

As a result, it is possible to simplify the process of manufacturing and assembling the head for forming the electrode in the common liquid chamber, to improve the productivity, and to prevent the cost of the head from being increased. For the wiring from the electrode for ink detection to the outside of the head, the method using a bonding wire, which is the same method as the signal line for sending a signal from the outside of the head to drive the heating resistor, is used as it is. Can,
No special steps or methods are required.

Next, the principle of detecting the presence or absence of ink in the present embodiment having the above configuration will be described.

When performing the value processing of the presence or absence of ink, first, a voltage is applied to the terminals 12a and 12b of the head from a power supply (not shown). Thereby, the wiring 11 in the PCB 10
A voltage is applied between the first ink detection electrode 8 in the common liquid chamber 1 and the second ink detection electrode 13 in the ink flow path via a and b. By measuring the current flowing between the head terminals 12a and 12b by the above-described detection circuit 1720 in the printer main body, the resistance value between the ink detection electrodes can be known.

When ink is present in the common liquid chamber 1 and the ink flow path 2, a current flows between the electrodes 8 and 13 via the ink. On the other hand, if there is no ink in the common liquid chamber 1 or the ink flow path 2, or if ink is cut off in a part between the electrodes due to bubbles or the like, an air layer will be interposed between the electrodes. Then, the resistance between the electrodes increases, and the current stops flowing.

That is, when there is no ink in the common liquid chamber 1, a small detection current can be obtained. For this reason, the detection circuit 1720 may convert the detected current value from analog to digital once, and then determine whether the detected current value is equal to or greater than a predetermined threshold value. This judgment is made, for example, by M
The determination can be made by the PU 1701, whereby the presence or absence of ink in the common liquid chamber 1 and the ink flow path can be known.

In this embodiment, only the presence / absence of ink has been described. However, this configuration can detect not only the presence / absence of ink but also the state of ink. For example, even when ink is present in the ink flow path and a detection current flows, when bubbles are generated in the flow path, the resistance value between the electrodes is detected higher than in a normal state. The detected resistance value follows the size and amount of the bubble. In this way, it is possible to detect not only the presence / absence of ink but also the state of ink in the same configuration.

In the above-described method of measuring the presence or absence of the ink, the time required for the detection is sufficient if the time for the current to flow through the ink is sufficient. There is no time consuming detection. Further, since it is not necessary to move the recording head to a predetermined position for detection as in the conventional ink droplet optical detection method, the detection can be performed without substantially lowering the 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 the detection voltage only at the time of detecting the presence / absence of ink in the common liquid chamber, and to perform discharge between the electrodes after the detection.

The recording operation in the present embodiment having the above configuration will be described below with reference to the flowchart of FIG.

When there is no input of print data, the print head performs a capping process for preventing nozzles from sticking by ink as shown in step S1 of FIG.
In step S2, the arrival of recording data is monitored, and if there is no recording data, the capping processing state in step S1 is maintained.

When the recording data is input, the process proceeds from step S2 to step S3, in which the recording head is scanned in a certain direction of the recording medium to start the recording operation. Subsequently, at step S4, at the start of the recording, the detection circuit 1720 applies a voltage between the two electrodes to measure a resistance value between the first electrode and the second electrode, and determines whether the resistance value is equal to or less than a predetermined threshold value. Is detected as described above. As a result, if it is determined in step S5 that there is no ink, the process proceeds to step S6, where the recording operation is stopped and the recording head is made to wait at the capping position. In step S7, a warning display of an ink error is displayed on a display (not shown). As a result, the user is notified that there is no ink, and the recording operation is stopped by, for example, performing the capping process in step S1.

On the other hand, if it is determined in step S5 that there is ink, the flow advances from step S5 to step S10 to execute a normal printing operation. And step S11
To check if a certain time has passed. Here, if the predetermined time has elapsed, the process returns to step S4, shifts to the process of detecting the presence or absence of ink, and performs a periodic ink detection operation at a predetermined timing during recording.

If it is determined in step S11 that the predetermined time has not elapsed, the flow advances to step S12 to check whether or not all the recording operations have been completed. If the recording operation has not been completed, the process returns to step S10, and the recording operation is continued. When all the recording operations are completed, the recording operation is stopped, and the process proceeds to, for example, the capping operation in step S1.

As described above, according to the embodiment of the present invention, the steps for forming the electrodes are reduced by forming the first electrodes simultaneously with the formation of the heater board substrate in the common liquid chamber of the ink jet recording apparatus. To improve head productivity and reduce head costs.
It is possible to detect the presence / absence of ink in the print head that requires less time for detection.

Further, by combining with the discharge stabilizing operation and the warning display function, it is possible to improve the reliability of the printer body, prevent the recording head from being damaged and the recording data from being lost, and improve the reliability as an ink jet recording apparatus. Can be improved.

(Second Embodiment) Hereinafter, a second example of the embodiment of the present invention according to the present invention will be described. The first mentioned above
In the embodiment, the first electrode is provided in the common liquid chamber 1,
Although the second ink detection electrode is provided in the ink flow path 2, the present invention is not limited to the above configuration example, and the second ink detection electrode is provided in the ink tank 6. You may. A second embodiment configured as described above will be described below.

FIG. 7 is a side sectional view of a print head of a thermal ink jet apparatus according to a second embodiment of the present invention. 7, the same components as those in the first embodiment shown in FIG. 3 described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 7, the second ink detecting electrode is provided not in the ink flow path but in the ink tank 6. Reference numeral 73 denotes a second ink detecting electrode according to the second embodiment, and a detection circuit 17 of the printer main body is connected to the outside of the ink tank 6 from the electrode 73 by a wiring 19.
20 and a power supply.

In the first embodiment described above, since the second ink detecting electrode is provided in the ink flow path 2,
The size and position can be very limited within the ink flow path. In particular, the size of the electrode greatly affects the detection sensitivity. Further, it is possible to determine the presence / absence of ink only in the ink between the common liquid chamber 1 and the second ink detection electrode portion in the ink flow path, and to determine the presence of ink on the upstream side from the second electrode to the ink tank. The presence or absence of ink cannot be detected.

In the second embodiment, with respect to such a problem, by providing the second electrode in the ink tank 6, the size can be relatively freely set in the ink tank. By arranging the ink in the ink tank and the head immediately adjacent to the junction point, the ink in the common liquid chamber 1 and the entire ink in the ink tank flow path 2 can be more reliably detected.

As described above, according to the second embodiment, in addition to the functions and effects of the above-described first embodiment, the entire ink in the common liquid chamber and the ink tank flow path can be more reliably removed. An effect that can be detected is obtained.

(Third Embodiment) Hereinafter, a third embodiment of the present invention according to the present invention will be described. The solution of the problem in the first embodiment is not limited to the configuration example of the second embodiment described above, and the second ink detecting electrode may be provided at the junction between the ink tank and the head. Good. The third embodiment configured as described above will be described below.

FIG. 8 is a side sectional view of a print head of a thermal ink jet apparatus according to a third embodiment of the present invention. 8, the same components as those in the first embodiment shown in FIG. 3 described above are denoted by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 8, reference numeral 20 denotes a filter on the head side at the junction between the ink tank and the head. The filter 20 has a function of preventing dust or the like mixed in the tank when the tank is attached or detached or the like from being mixed into the head and affecting the ejection characteristics. Usually, a mesh of stainless steel or the like is used.

In the third embodiment, attention is paid here, and such a conductive material is used for the filter 20, and the conductive filter 20 is used as the second ink detecting electrode. A wire is connected from the filter 20 to the head terminal 19 via the wire 14, and is connected to a detection circuit 1720 of the printer main body and a power supply.

In the configuration of the third embodiment, since the configuration is as described above, the presence or absence of ink in the entire ink flow path can be detected. In addition, since the entire filter can be used as an electrode, the electrode area can have an area equivalent to the cross section of the flow path.
It can be larger than when it is built in the flow path,
The detection accuracy is further improved. Further, in the above-described first and second embodiments, a material and a process for newly forming the second ink detecting electrode in the head or the tank are required. However, in the third embodiment, In this case, since the filter provided conventionally can be used as it is, the cost can be reduced.

(Fourth Embodiment) In the above-described embodiment, the case where only one common liquid chamber is provided in the recording head has been described, but a plurality of separated common liquid chambers are provided in one recording head. There is a recording head, which is usually used for color inkjet. A fourth example of the embodiment of the present invention according to the present invention in which only one common liquid chamber is provided in the recording head will be described below with reference to FIG.

FIG. 9 is a front view of a heater board substrate of a recording head according to the fourth embodiment. The fourth shown in FIG.
In this embodiment, different colors of ink are supplied into the respective common liquid chambers of the recording head. In the example of FIG. 9, four colors of ink (black, yellow,
(Magenta, cyan) for a recording head having four common liquid chambers. However, the present invention is not limited to the above four examples, and the color type, type, and the number of common liquid chambers of the ink common to each of the common liquid chambers having an h difference or more are not particularly limited.

Reference numeral 4 denotes a heater board.
Reference numeral 4 denotes a common liquid chamber for each ink. Since the heater board 4 is common to the four colors, the ink detection electrodes in the common liquid chamber are
The color can be common. As described in the first to third embodiments, the second electrode is provided in each color ink channel, ink tank, or filter. By switching the second detection electrode, it is possible to detect which color ink has run out. Conventionally, such a head having a plurality of liquid chambers separated in one recording head requires a pair of detection electrodes for each color. However, according to this embodiment, the first electrode can be shared. In addition, the number of detection electrodes can be reduced, and the cost can be reduced.

(Fifth Embodiment) In the first embodiment, when there is no ink in the common liquid chamber, recording is not performed, capping is performed, and an ink error is displayed. However, the user must then perform some kind of recovery suction operation or replace the tank. Therefore, after detecting the absence of ink, the main body automatically performs predetermined suction recovery. 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. Otherwise, printing is restarted again.

These operations can improve the reliability and operability of the printer main body.

(Sixth Embodiment) In an ink jet recording apparatus, there is usually no ink in the common liquid chamber when there is no ink in the common liquid chamber and when there is ink in the ink tank. It is conceivable that there is no ink in both tanks, but this determination cannot be made in the first embodiment. Therefore, after detecting the ink presence / absence in the common liquid chamber and detecting the absence of ink, the predetermined suction recovery operation is performed once or plural times, and then the presence / 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 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.

(Seventh Embodiment) In the ink jet recording apparatus, if the ink jet recording apparatus is not used for a certain period, bubbles may be generated in the common liquid chamber and the flow path from the ink tank. Assuming such a case, when the printer has not been used for a certain period or more, the volume from the common liquid chamber of the head to the ink tank is sucked immediately before the subsequent use of the printer. However, in such a case, the ink is not always depleted depending on the environment where the printer body is left. In such a case, there is no ink in the common liquid chamber after being left as it is, there are cases where there is no ink in the common liquid chamber and there is ink in the ink tank, and where there is no ink in both the common liquid chamber and the ink tank. In the first embodiment, this determination cannot be made. Therefore, after detecting the presence / absence of ink in the common liquid chamber, the presence / 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 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.

(Eighth Embodiment) In the above embodiment, current flows from the electrode to the ink for ink detection. However, a considerable amount of electrolysis occurs on the electrode surface, and the deterioration of the ink detection electrode is reduced. Can happen. 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 electrolysis with the ink may be a reversible reaction. Therefore, an AC voltage is applied to the ink detection electrode. When the polarity of the electrode at the time of electrolysis changes, a chemical reaction opposite to the previous reaction is caused to prevent deterioration of the electrode. By applying the AC voltage to the electrodes as described above, deterioration of the electrodes can be prevented, and the reliability of detection can be increased.

(Ninth Embodiment) 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.

That is, the capacitance between the ink detection electrodes 8 and 13 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, if the detection circuit 1720 is changed to a circuit for measuring the electric resistance value between the two electrodes and a circuit for measuring the capacitance between the two electrodes, the capacitance between the electrodes can be measured by measuring the capacitance between the electrodes. Can be detected.

(Other Embodiments) Even if the present invention is applied to a system constituted by a plurality of devices (for example, a host computer, an interface device, a reader, a printer, etc.), an apparatus (one device) For example, the present invention may be applied to a copying machine, a facsimile machine, and the like.

Further, an object of the present invention is to provide a storage 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 (or CPU) of the system or apparatus.
And MPU) read and execute 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.

Examples of the storage medium for supplying the program code include a floppy disk, hard disk, optical disk, magneto-optical disk, CD-ROM, and CD.
-R, a magnetic tape, a nonvolatile memory card, a ROM, or the like can be used.

When the computer executes the readout program code, not only the functions of the above-described embodiment are realized, but also the OS (Operating System) running on the computer based on the instruction of the program code. ) 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 a memory provided in a function expansion board inserted into the computer or a function expansion unit connected to the computer, based on the instructions of the program code, It goes without saying that the CPU included in the function expansion board or the function expansion unit performs part or all of the actual processing, and the processing realizes the functions of the above-described embodiments.

[0096]

As described above, according to the present invention, the presence / absence of ink that can be printed out by an ink jet recording apparatus can be reliably detected with a simple configuration. Furthermore, by combining with the discharge stabilization operation and the warning display function,
It is possible to improve the reliability of the printing apparatus main body, prevent printhead destruction and print data loss, and improve the reliability of the ink jet printing apparatus.

Further, by sharing the detection electrode for detecting the presence or absence of ink with a member having another function, it is possible to greatly reduce the manufacturing cost of the apparatus by simplifying the configuration.

[Brief description of the drawings]

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

FIG. 2 is a block diagram illustrating a configuration of a control circuit of the inkjet printer IJRA according to the present embodiment.

FIG. 3 is a side sectional view of a print head of a thermal inkjet device used in an example of an embodiment of the present invention.

FIG. 4 is a plan view of a heater board substrate in the print head shown in FIG.

FIG. 5 is a diagram showing a cross section of the heater board substrate of the present embodiment.

FIG. 6 is a flowchart illustrating a recording operation according to the embodiment.

FIG. 7 is a side sectional view of a print head of a thermal inkjet apparatus according to a second example of the embodiment of the present invention.

FIG. 8 is a side sectional view of a print head of a thermal inkjet apparatus according to a third embodiment of the present invention.

FIG. 9 is a front view of a heater board substrate of a print head of a thermal ink jet apparatus according to a fourth embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Common liquid chamber 2 Ink flow path 3 Nozzle 4 Heater board substrate 5 Heating resistor 6 Ink tank 7 Top plate 8 First ink tank presence / absence detection electrode 9 Bonding wire 10 PCB 11 PCB internal wiring 12 Head terminals 13, 73 Second ink tank detecting electrode 14 Wiring 15 Silicon substrate 16 First insulating layer 18 Second insulating layer 20 Second ink detecting electrode also serving as filter

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

Claims (21)

[Claims] An ink state detecting mechanism for an ink jet recording apparatus for supplying ink from an ink tank into a common liquid chamber in a recording head and discharging the ink in the common liquid chamber from a nozzle at the tip of the recording head for recording. A first detection electrode provided in at least one common liquid chamber; and a second detection electrode provided in an ink flow path from at least one ink tank to the common liquid chamber. An ink state detection mechanism for an ink jet recording apparatus, wherein an ink state between the first detection electrode and the second detection electrode can be detected. 2. An ink state detecting mechanism of an ink jet recording apparatus for supplying ink from an ink tank into a common liquid chamber in a recording head and discharging the ink in the common liquid chamber from a nozzle at the tip of the recording head to perform recording. A first detection electrode provided in at least one of the common liquid chambers; and a second detection electrode provided in at least one ink tank. An ink state detection mechanism for an ink jet recording apparatus, wherein an ink state between the second detection electrodes can be detected. 3. An ink state detecting mechanism of an ink jet recording apparatus for supplying ink from an ink tank into a common liquid chamber in a recording head and discharging the ink in the common liquid chamber from a nozzle at a tip end of the recording head for recording. A first detection electrode disposed in at least one of the common liquid chambers; and a second detection electrode disposed in an ink flow path from at least one ink tank to the common liquid chamber and in the ink tank. An ink state detection mechanism for an ink jet recording apparatus, comprising: a detection electrode; and an ink state between the first detection electrode and the second detection electrode. 4. The apparatus according to claim 1, further comprising a first detection unit that detects a resistance value between the first detection electrode and the second detection electrode to detect a state of ink between the quantity electrodes. An ink state detection mechanism for an ink jet recording apparatus according to any one of claims 1 to 3. 5. The ink-jet apparatus according to claim 4, wherein said first detection means detects an ink state by applying an AC voltage to said first detection electrode and said second detection electrode. An ink state detection mechanism of the recording device. 6. The apparatus according to claim 1, further comprising a second detection unit configured to detect a capacitance between the first detection electrode and the second detection electrode to detect a state of ink between the two electrodes. 4. An ink state detecting mechanism for an ink jet recording apparatus according to claim 1, wherein: 7. A heater board substrate is disposed in a common liquid chamber of the ink jet recording apparatus, a heating resistor is disposed on the heater board substrate, and a voltage is applied to the heating resistor to generate the heating resistor. An ink jet recording apparatus that performs recording by heating an ink on a body to foam and change a physical volume to discharge ink droplets from a nozzle at a tip of a recording head, wherein the uppermost layer of a heater board substrate in the recording head is provided. 7. A thin film having a cavitation resistance and conductivity made of an ink-resistant material is formed thereon, and said thin film is used as a first detection electrode in a common liquid chamber. An ink state detection mechanism for the ink jet recording apparatus according to any one of the above. 8. The ink state detection of an ink jet recording apparatus according to claim 7, wherein the thin film formed on the uppermost layer of the heater board substrate is a Ta thin film and the Ta thin film is the first detection electrode. mechanism. 9. The ink jet recording according to claim 1, wherein the second detection electrode is provided near a joint between the ink tank and a recording head. The ink status detection mechanism of the device. 10. The ink state of the ink jet recording apparatus according to claim 9, wherein the second electrode has a filter function for removing dust and the like in the ink at the junction between the recording head and the ink tank. Detection mechanism. 11. The ink-jet recording apparatus according to claim 1, wherein a plurality of common liquid chambers are provided in one recording head, and the first detection electrode in each common liquid chamber is a common electrode. 11. The ink state detection mechanism of the ink jet recording apparatus according to any one of 10. 12. The ink state detection mechanism according to claim 1, wherein the first detection electrode is set to a discharge state except when the ink state is detected. 13. The ink state detecting mechanism according to claim 4, wherein a warning is displayed when said detecting means detects that there is no ink. 14. The printing apparatus according to claim 1, wherein said detecting means detects an ink state during a printing operation.
An ink state detection mechanism for an ink jet recording apparatus according to claim 13. 15. The ink state detecting mechanism of an ink jet recording apparatus according to claim 14, wherein the recording operation is stopped when said detecting means detects the absence of ink. 16. The ink state detecting mechanism of an ink jet recording apparatus according to claim 14, wherein when the detecting means detects that there is no ink, the ejection stabilizing operation of the head is performed. 17. When the detecting means detects that there is no ink, the warning is displayed, the ejection stabilizing operation of the head is automatically performed, and then the presence or absence of ink is detected again. An ink state detection mechanism for an ink jet recording apparatus according to claim 16. 18. The recording head has at least two common liquid chambers, and displays a warning when the detection means detects that there is no ink in at least one of the plurality of common liquid chambers. 7. An ink state detecting mechanism for an ink jet recording apparatus according to claim 4, wherein 19. The ink state detecting mechanism of an ink jet recording apparatus according to claim 18, wherein said detecting means detects an ink state during a printing operation and stops the recording operation when detecting the absence of ink. . 20. The ink state detecting mechanism of an ink jet recording apparatus according to claim 18, wherein when the detecting means detects that there is no ink, the ejection stabilizing operation of the head is performed. 21. An ink jet recording apparatus comprising the ink state detection mechanism according to any one of claims 1 to 20.