JP2010064444A - Inkjet recording device and method for controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inkjet recording device which keeps film boiling phenomenon of ink stabilized and generates no fluctuation of discharge speed, discharge direction and discharge amount of ink even when energy inputted to an inkjet recording head is insufficient. <P>SOLUTION: The inkjet recording device includes a nonejection nozzle detecting means for detecting a nonejection nozzle among ejection nozzles constituting an inkjet recording head, a drive condition detecting means for detecting a drive condition of the inkjet recording head when the nonejection nozzle is detected, and a change means which, when detecting that the drive condition is different from a drive condition stored in the inkjet recording head, rewrites the drive condition stored in the inkjet recording head, and changes a drive energy supplied when driving the inkjet recording head. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an ink jet recording apparatus that forms an image using an ink jet recording head in which bubbles generated in ink are grown and contracted by a heating resistor element, thereby ejecting ink from an ejection port. More specifically, the present invention relates to a processing method for detecting a non-ejection nozzle in an ink jet recording head used in an ink jet recording apparatus.

  An ink jet recording head forms ink droplets by various methods, and records the ink droplets on a recording medium such as recording paper. In particular, an ink jet recording head that uses thermal energy to generate film boiling in ink and eject the ink can easily be manufactured with a high-density liquid path arrangement (discharge port arrangement).

  In other words, through a semiconductor manufacturing process such as etching, vapor deposition, sputtering, etc., by forming a heating resistor element, electrode, liquid channel wall, top plate, etc. formed on the substrate, a high-density liquid channel arrangement (discharge port) Arrangement) can be manufactured easily. Therefore, high-density multi-nozzles can be easily realized and high-resolution and high-quality images can be obtained at high speed.

  In the case of an ink jet system having such a principle and structure, for example, a so-called ink non-ejection state may occur, such as thickening and solidification of ink in the ejection port, paper clogging, or failure of the heating resistor element itself.

In preparation for these, a non-ejection state is detected, and whether the cause is nozzle clogging or heater failure is distinguished. When the former is the cause, the recovery process is executed, and when the latter is the cause, the non-use process using the mask is performed. By these, it is possible to efficiently perform a recovery process, and to prevent a chain failure of the heater (see, for example, Patent Document 1).
JP 2007-320288 A

  However, when the cause of ink non-ejection is a heater failure, the threshold of driving energy required for ink ejection may increase in the ink jet recording head.

  In general, in an ink jet recording apparatus, an appropriate drive condition is obtained and set by multiplying a threshold value of drive energy necessary for ink ejection of the ink jet print head by a margin value k (hereinafter referred to as “k value”) obtained separately. To do. As a result, ink can be stably ejected.

  However, if the energy input to the ink jet recording head is insufficient, the ink film boiling phenomenon tends to become unstable, and the ink droplet ejection speed, direction, and ejection amount vary. As a result, there is a problem that the image quality of the recorded image is deteriorated, such as twisting, shobo, and blurring.

  The present invention provides an ink jet recording apparatus in which the ink film boiling phenomenon is stable even when the input energy to the ink jet recording head is insufficient, and the ink droplet ejection speed and direction and the ejection amount do not change. The purpose is to do.

  The present invention provides an ink jet recording apparatus that records ink by ejecting ink droplets from an ink jet recording head to a recording medium by driving a heating resistor element. Non-ejection nozzle detection means for detecting nozzles, driving condition detection means for detecting driving conditions of the inkjet recording head when non-ejection nozzles are detected among the ejection nozzles constituting the inkjet recording head, and the inkjet Changing means for rewriting the driving condition stored in the ink jet recording head and changing the driving energy supplied when driving the ink jet recording head when it is detected that the driving condition is different from the driving condition stored in the recording head Inkjet recording apparatus having It is.

  According to the present invention, since the drive energy suitable for the ink jet recording head is continuously provided after the detection process of the ink non-ejection nozzle due to the heater failure, it is possible to prevent the ejection failure of the ink droplets, and to always provide a good image quality. There is an effect that it can be provided.

  As a result, there is an effect that the image quality of the recorded image does not deteriorate, such as twist, shobo, and blur.

  The best mode for carrying out the invention is the following embodiment.

[overall structure]
FIG. 1 is a schematic view showing an ink jet recording apparatus 1000 that is Embodiment 1 of the present invention.

  The lead screw 1004 is rotated forward and backward through the driving force transmission gears 1002 and 1003 by forward and reverse rotation of the carriage motor 1001. The carriage CR has a pin (not shown) that engages with the spiral groove of the lead screw 1004 and is reciprocated in the directions of arrows a and b in FIG. 1 according to the direction of rotation of the lead screw 1004. A head cartridge HC is mounted on the carriage CR. The head cartridge HC is composed of an ink jet recording head IH and an ink tank IT.

  The ink jet recording apparatus 1000 is a recording apparatus generally called a serial printer, and repeats main scanning along the directions of arrows a and b of the carriage CR and sub scanning of the recording sheet 1005 as a recording medium. Recording is performed on the entire surface of the recording sheet 1005.

  A suction recovery system unit 1006 is provided on the left end side of the movable region of the carriage CR so as to face each ink discharge port of the recording head IH on the carriage CR. The suction recovery system unit 1006 includes a cap member 1007, a wiper blade 1008, a pump (not shown) for sucking ink from each nozzle through the ink path, and the like. The cap member 1007 caps the face surface of the recording head IH. The wiper blade 1008 wipes the face surface of the recording head IH.

  The suction recovery system unit 1006 executes a suction recovery operation for maintaining a good ink discharge state of the recording head IH.

[Recording head]
FIG. 2 is a diagram illustrating a configuration example of the inkjet recording head IH.

  The ink jet recording head IH has a side shooter type head structure in which the ink discharge direction is perpendicular to the heater surface of the heating element. The first embodiment may be applied to an edge shooter type head whose ink discharge direction is parallel to the heater surface.

  In the side shooter type ink jet recording head IH, a plurality of ink discharge ports 2001 are arranged in a staggered manner on both sides of the ink supply port 2003. In the ink jet recording head IH, an electrothermal transducer 2002 that generates thermal energy for ejecting ink droplets from each ink ejection port 2001 is provided on the substrate 2005 for each ink flow path 2004. . Each electrothermal transducer 2002 is an example of a recording element, and is mainly composed of a heating resistance element, electrode wiring for supplying power to the heating resistance element, and a protective film for protecting these from ink (not shown). ).

  The ink supply port 2003 is generally formed by dicing, sandblasting, anisotropic etching, or the like, and FIG. 2 shows the ink supply port 2003 formed by anisotropic etching with high processing accuracy. When the processing accuracy of the ink supply port 2003 is low, the distance from the end of the ink supply port to the electrothermal transducer 2002 is different in each ink flow path 2004, and the current resistance varies, and the ink discharge ports 2001 are discharged. The ink droplet ejection amount fluctuates, degrading the quality of the recorded image. For this reason, the processing accuracy of the ink supply port 2003 is an important factor.

  As a method for forming the ink discharge port 2001, there is a method in which a film made of polyimide or the like that has been processed and formed in advance by laser processing or the like is bonded onto the substrate 2005. As another method, there is a method in which a resin material or the like is coated on the substrate 2005 and formed by exposure development or plasma etching using a photolithography technique. In view of the recent increase in demand for photo prints, it is expected that the demand for the accuracy of ink droplet landing will increase further in the future. Therefore, from the viewpoint of the processing accuracy of the ink discharge port 2001 and the positional accuracy of the electrothermal transducer 2002, a formation method on the substrate 2005 using a photolithography technique is advantageous.

  In the side shooter type ink jet recording head IH having the above-described configuration, the ink is held in the vicinity of the plurality of ink discharge ports 2001 while forming a meniscus. At this time, the plurality of electrothermal transducers 2002 are selectively driven in accordance with image recording information or the like, whereby the ink on the heat acting surface of the heating resistor element is heated and boiled rapidly. Ink droplets are ejected by vigorous force.

[Undischarge detection unit]
FIG. 3 is a schematic diagram illustrating a nozzle detection configuration 3000 in which ink is not ejected from the inkjet recording head IH.

  The light beam 3001 is a light beam that is narrowly narrowed and output from the light emitting unit 3002, and the ink droplets 3004 and 3005 are ejected from the ejection port while the head 3003 is moving in the main scanning so as to block the optical axis of the light beam 3001. 3xxx is discharged. The light beam 3001 is received by the light receiving unit 3007 and the light intensity is detected. The member 3008 is a member that receives ink ejected for ink droplet detection during the processing.

[Recording head pad section]
FIG. 4 is a diagram showing the configuration of the contact pad electrode portion 4000 of the ink jet recording head.

  The contact pad electrode portion 4000 includes a VH electrode 4001, a GNDH electrode 4002, a VHT electrode 4003, a VDD electrode 4004, a GNDL electrode 4005, and a plurality of signal lines and non-contact pads 4006.

  Here, only the GNDL electrode 4005 is electrically connected to the substrate 2005 made of silicon and has the same potential. Further, conventionally, for the purpose of stabilizing the operation, the gate voltage VHT of the power transistor (n-MOS) for driving the heating resistor element is a power supply pad (= VH electrode) for applying driving energy to the heating resistor element. ) It was taken out from 4001. However, in the first embodiment, the VHT electrode 4003 is provided separately from the VH electrode 4001.

  Next, a leakage current that flows when ink is conducted to the electrothermal converter 2002 due to a heater failure or the like and a voltage is applied to the VH electrode 4001 will be described.

  FIG. 5 is a diagram illustrating a change in leakage current over time.

  When the VH voltage is applied in a state where the heating resistance element is in conduction with the ink that has passed through the protective film and entered, immediately after that, a current of about several tens mA to several hundred mA flows, but gradually decreases with time. Finally, it becomes approximately 0 A (μA order).

  In the first embodiment, current leakage is detected through ink by utilizing such a characteristic of current. That is, ink that has entered through the protective film is electrically connected to the electrothermal transducer 2002. Since the ink is in contact with the substrate 2005 made of silicon through the ink supply port 2003, the ink is electrically connected to the GNDL electrode 4005. Therefore, the two electrodes of the VH electrode 4001 and the GNDL electrode 4005 function as current leak detection electrodes via ink.

[Control system]
6 and 7 are block diagrams showing a control system used in an ink jet recording apparatus equipped with an ink jet recording head.

  In FIG. 6, character and image data to be recorded (hereinafter referred to as “image data”) is input to the reception buffer 6001 of the inkjet recording apparatus 1000 from the host computer. In addition, data for confirming that data is correctly transferred, and data for notifying the operation state of the ink jet recording apparatus 1000 are output from the ink jet recording apparatus 1000 to the host computer. The data in the reception buffer 6001 is transferred to the memory unit 6003 under the management of the control unit (CPU) 6002 and temporarily stored in a RAM (random access memory).

  A mechanical control unit 6004 drives a mechanical unit (mechanical unit) 6005 such as a carriage motor 1001 or a line feed motor in response to a command from the control unit 6002.

  The sensor / SW control unit 6006 sends a signal from the sensor / SW unit 6007 including various sensors and SW (switch) to the control unit 6002. A display element control unit 6008 controls a display element unit 6009 including LEDs of a display panel group, a liquid crystal display element, and the like according to a command from the control unit 6002.

  The recording head control unit 6010 controls driving of the recording head IH according to a command from the control unit 6002, detects temperature information indicating the state of the recording head IH, and the like and transmits them to the control unit 6002.

  Inside the ink jet recording head IH, as described above, an electrothermal transducer 2002 for ejecting ink droplets, an electric circuit for controlling the heater, and a heater that is a Si substrate on which drive elements are integrated A board (element substrate) is arranged. A head temperature detection sensor 7001 for detecting the temperature of the recording head IH is disposed on the heater board. In the first embodiment, the head temperature detection sensor 7001 detects the temperature using the temperature characteristic of the output voltage of the diode. However, the element using the temperature characteristic of the resistance value of the electrical resistor, You may make it use the thing of a system.

  Further, on the recording head IH side, a memory unit 6003 is provided for storing information used by the recording apparatus main body to determine driving energy input when driving each electrothermal transducer 2002 of the head IH. Yes. Information used to determine the drive energy to be input when driving each electrothermal transducer 2002 includes initial suitable drive condition data (drive energy, drive voltage, drive pulse width, etc.), various corrections. Data or head usage history data.

  As the memory unit 6003, in addition to an EEPROM (Electrical Erasable Programmable ROM), a fuse ROM, a rank resistance formed in the same process as the electrothermal converter 2002, or the like may be used. However, when a fuse ROM, rank resistance, or the like is used, it is impossible to rewrite the information in the memory unit 6003. In such a case, when appropriate driving conditions change and information related thereto is stored. For this, the memory on the recording apparatus main body side is used.

  Detection temperature data of the head temperature detection sensor 7001 is input to a head temperature detection circuit 7005 on the recording apparatus main body side via a signal line (flexible wiring).

  On the recording apparatus main body side, the head temperature detection circuit 7005 includes a detection circuit, an A / D conversion circuit, a circuit that converts / corrects A / D conversion data into a format that can be used for control, and the like. The detection circuit receives an output signal from the head temperature detection sensor 7001. The A / D conversion circuit converts the output signal of the detection circuit into digital data. The output here is treated as the head temperature and used for various controls such as PWM control of the head drive pulse (pulse width modulation control with respect to the head temperature).

  The environmental temperature detection sensor 7006 detects the ambient temperature of the recording head IH, and uses, for example, a thermistor provided on a substrate disposed on a carriage HC on which the head IH is mounted. Similar to the head temperature detection circuit 7005, the environmental temperature detection circuit 7007 includes a circuit for detecting the output of the thermistor, an A / D conversion circuit, a correction / conversion circuit, and the like. The output here is treated as an environmental temperature, and is used for performing heat insulation control according to a change in the environmental temperature.

  The head drive control unit 7008 performs electrical heat in the recording head IH based on the head temperature detection value from the head temperature detection circuit 7005, the environmental temperature detection value from the environmental temperature detection circuit 7007, information from the print control unit 7009, and the like. The drive condition of the converter 2002 is determined. Then, a drive signal is generated to perform the above head heat retention control.

  The print control unit 7009 determines which nozzle is actually driven and which ink droplet is ejected at what timing according to the print data from the host computer, the conditions such as the print mode set by the user with the panel and the like. . In accordance with this, control such as determining the drive timing and drive amount of the carriage motor 1001 for driving the carriage CR and the paper feed motor is executed.

  The undischarge nozzle detection sequence determination unit 7013 determines whether or not to perform an undischarge nozzle detection sequence based on the use history of the head included in the memory unit of the recording head IH and the information on the number of drive pulses from the print control unit. To do. Here, if the undischarge nozzle detection sequence is selected, this is transmitted to the print control unit 7009, and various sequence operations are started by signals from here.

  When the sequence operation is started, the discharge failure nozzle detection unit 7003 discharges ink droplets from the discharge port so as to block the optical axis of the light beam that is narrowly narrowed and output from the light emitting unit 3002. The light beam is received by the light receiving unit 3007 and the light intensity is detected.

  When the heater failure detection sequence determination unit 7004 is selected to perform the heater failure detection sequence in accordance with the result of the undischarge nozzle detection sequence determination unit 7013, the fact is transmitted to the print control unit 7009, from which Various sequence operations are started by the signal. The heater failure detection unit 7014 applies a voltage to the contact pad electrode unit 4000 and detects a current leak from the electrothermal transducer 2002 to the ink.

  When the drive energy threshold detection sequence determination unit 7010 is selected to perform the drive energy threshold detection sequence according to the result of the heater failure detection sequence determination unit 7004, the fact is transmitted to the print control unit 7009. Various sequence operations are started by signals from here.

  When the sequence operation is started, the drive energy threshold detection unit 7011 sequentially receives drive energy information that is sequentially decreased from the head drive control unit 7008 and head temperature information from the corresponding head temperature detection circuit 7005. And the threshold value of drive energy is determined based on these information.

  The optimum drive energy detection unit 7012 obtains a suitable drive condition using the threshold value data determined by the drive energy threshold value detection unit 7011, and uses this suitable drive condition to store the head drive control unit 7008 and the memory unit of the recording head IH. Give feedback to 6003. That is, the previous drive condition data recorded in the memory unit 6003 is compared with the newly obtained drive condition data, and if the two are different, the previous data is updated with the current data.

  The control unit 6002 is an example of a non-ejection nozzle detection unit that detects non-ejection nozzles among the ejection nozzles constituting the inkjet recording head. The control unit 6002 is an example of a drive condition detecting unit that detects a drive condition of the inkjet recording head when a non-ejection nozzle is detected among the ejection nozzles constituting the inkjet recording head. The control unit 6002 is an example of a unit that rewrites the driving conditions stored in the inkjet recording head when it detects that the driving conditions are different from the driving conditions stored in the inkjet recording head. Moreover, the control unit 6002 is an example of changing means for changing the driving energy supplied when the ink jet recording head is driven.

  The ink jet recording head driving condition is a condition obtained by supplying a plurality of different driving energies to the ink jet recording head and monitoring the temperature of the ink jet recording head corresponding to each of the driving energy.

  The control unit 6002 is an example of a current leak detection unit that detects a current leak in the order of mA via the ink provided in the ink jet recording head. The control unit 6002 is an example of drive condition detection means for detecting the drive condition of the ink jet recording head when the current leak is detected. When the current leak is detected, the control unit 6002 is an example of a unit that rewrites the driving conditions stored in the ink jet recording head and changes the driving energy supplied when the ink jet recording head is driven.

  Further, a current flowing by applying a potential is measured between an electrode pad having the same potential as the silicon substrate on which the heating resistor element is formed and an electrode pad to which energy for driving the heating resistor element is applied. . As a result, current leakage through the ink provided in the ink jet recording head is obtained.

  The ink jet recording head driving condition is a condition obtained by supplying a plurality of different driving energies to the ink jet recording head and monitoring the temperature of the ink jet recording head corresponding to each of the driving energy.

  When a non-ejection nozzle is detected among the ejection nozzles constituting the inkjet recording head, and a current leak in the order of mA is detected via the ink provided in the inkjet recording head, the inkjet recording head Detect drive conditions. In addition, the drive energy supplied when the ink jet recording head is driven is changed.

  Then, a potential is applied between an electrode pad having the same potential as the silicon substrate on which the heating resistor element is formed and an electrode pad to which energy for driving the heating resistor element is applied, and the flowing current is measured. As a result, current leakage through the ink provided in the ink jet recording head is obtained.

  The ink jet recording head driving condition is a condition obtained by supplying a plurality of different driving energies to the ink jet recording head and monitoring the temperature of the ink jet recording head corresponding to each of the driving energy.

  Next, the operation of the first embodiment will be described.

  FIG. 8 is a flowchart illustrating an operation procedure in the first embodiment.

  First, when a discharge failure detection command is received from the main body, it is checked in S11 whether there is a history of heater failure in the past. If there is no history of heater failure in the past, the optical sensor detects an undischarge nozzle in S12. As a result, if a non-ejection nozzle is detected, in S13, the nozzle is disabled and registered by mask processing or the like. Thereafter, in S14, it is determined whether or not all nozzles have been inspected.

  After all nozzle inspections are completed, if an undischarge nozzle is detected in S15, the discharge threshold is measured.

  In the memory unit 6003 of the recording head IH, as described above, a voltage (K · Vth) obtained by multiplying the ink discharge threshold voltage Vth measured in advance by a predetermined margin value K is stored as a suitable head driving voltage Vop. is doing. Therefore, when driving each electrothermal transducer 2002 of the recording head IH, the head drive control unit 7008 reads a suitable head drive voltage Vop from the memory unit 6003 and determines an actual drive voltage based on the voltage value Vop. To do.

  In the first embodiment, driving energy that sequentially decreases is supplied to each electrothermal transducer 2002 of the recording head IH, and the head temperature corresponding to each driving energy is measured. At this time, in the first embodiment, the head drive voltage V is fixed, and the pulse width Pw of the drive pulse signal applied to the electrothermal transducer 2002 is changed (gradually shortened). The head driving voltage Vop multiplied by the margin value k stored in the memory unit 6003 of the recording head IH is employed as it is as the fixed head driving voltage V. In this case, the voltage is fixed and the pulse width is changed, so that the drive energy changes depending on the pulse width.

  When the drive energy threshold detection sequence is started, the head drive voltage V is fixedly set at (Vop) (S18).

  Next, the measurement start value of the pulse width Pw is determined based on the information stored in the memory unit 6003 of the recording head IH. As this measurement start value, a higher value that ensures ejection of ink droplets is employed.

  When the supply start pulse width Pw is determined (S18a), the recording head is driven for a certain period by a predetermined driving pattern set in advance using the determined pulse width Pw and the head driving voltage V (S19). ). Normally, all the heating resistance elements are driven, but some selected heating resistance elements may be driven as long as the head temperature change can be reliably detected. Here, a predetermined drive pattern and a certain period are determined according to the nozzle to be used, the drive frequency, the number of drive pulses, and the like.

  Immediately after the end of the head drive for a certain period, the head temperature T detected by the head temperature detection sensor 7001 is acquired (S20). The acquired head temperature T is stored in the drive energy threshold detection unit 7011 in a format associated with the pulse width Pw at this time.

  Next, the pulse Pw is reduced by a predetermined value (the resolution with variable pulse width possessed by the head drive circuit), and the recording head is driven again for a certain period by the same drive pattern as the previous time. T is acquired (S22 to S20). The acquired head temperature T is also stored in the drive energy threshold detection unit 7011 in a format associated with the pulse width Pw at this time.

  A series of these processes is repeatedly executed to obtain a threshold pulse width Pth for determining the presence or absence of ink ejection (S23).

  The threshold pulse width Pth can be obtained by detecting the inflection point or the minimum temperature value from the data indicating the correspondence relationship between the stored pulse width Pw and the head temperature T.

  FIG. 11 is a diagram illustrating a correspondence relationship between the head temperature T stored in the drive energy threshold value detection unit 7011 and the pulse width Pw (drive energy E).

  In FIG. 11, the boundary between the B region and the C region is the threshold value Pth of the pulse width Pw. In this case, in the region B, the head temperature T increases as the pulse width Pw becomes smaller. This is considered to be because ejection / non-ejection is mixed due to variations in a plurality of nozzles. .

  In the region C, as the pulse width Pw increases, the surplus energy is supplied to the recording head in addition to the energy necessary for ejecting the ink droplets, so that the head temperature rapidly increases.

  On the other hand, in the area A in FIG. 11, since the ink droplets are not ejected due to insufficient energy, heat is not radiated from the head due to the ink droplets, and the supplied energy contributes exclusively to an increase in the head temperature. Will rise regularly.

  As shown in FIG. 11, the head temperature rise pattern is significantly different between when ink droplets are ejected and when ink droplets are not ejected. Therefore, the drive energy threshold detection unit 7011 can obtain the drive pulse threshold Pth by analyzing the data pattern indicating the correspondence relationship between the stored pulse width Pw and the head temperature T.

  In the case of Example 1, since an appropriate drive voltage Vop is used as it is at the time of measurement, a value obtained by multiplying the calculated pulse width threshold Pth by K2 (because the pulse width has a square root relationship with the voltage) is appropriate. The value Pop is used. Of course, Vop is also a suitable driving voltage in this case.

  The optimum drive energy detection unit 7012 obtains a suitable drive pulse width Pop as described above (S24), and the drive drive width stored in the memory unit 6003 of the recording head IH is obtained from the obtained suitable drive pulse width Pop. The drive pulse width in the condition data is compared (S25). If they are different from each other, feedback is given to the memory unit 6003 and the head drive control unit 7008 of the recording head IH, the stored information in the memory unit 6003 is updated with the new data Pop, and the drive of the head drive control unit 7008 is performed. The condition is changed (S26).

  However, as described above, when a non-rewritable memory element such as a fuse ROM or the rank resistor is used as the memory unit 6003, the memory unit 6003 is not rewritten, and the drive condition of the head drive control unit 7008 Only the setting is changed.

  FIG. 9 is a flowchart showing the operation of the ink jet recording apparatus which is Embodiment 2 of the present invention.

  The configuration of the second embodiment is the same as the configuration of the ink jet recording apparatus 1000 that is the first embodiment.

  First, when a failure heater detection command is received from the main body, a voltage is applied to the VH electrode 4001 in S16. Then, immediately after the voltage is applied with VDD set to 5V and VH set to 11V (S16a), if an ink leak occurs inside the recording head, a leak current flows, so this leak current is measured. In S17, it is determined whether or not the leakage current has been detected. That is, the normal current value is almost zero A (μA order), but if ink leakage occurs, a current of mA order flows, and if this leakage current is detected, the process proceeds to a discharge threshold measurement step in S18. move on. If the leakage current cannot be detected, the discharge failure detection process is terminated.

  As described above, the memory unit 6003 of the recording head IH stores a voltage (K · Vth) obtained by multiplying the ink discharge threshold voltage Vth measured in advance by a predetermined margin value K as an appropriate head driving voltage Vop. ing. Therefore, the head drive control unit 7008 reads the suitable head drive voltage Vop from the memory unit 6003 when driving each electrothermal transducer 2002 of the recording head IH, and based on this voltage value Vop, the actual drive voltage To decide.

  In the second embodiment, the drive energy that sequentially decreases is supplied to each electrothermal transducer 2002 of the recording head IH, and the head temperature corresponding to each drive energy is measured. At this time, in Example 2, the head drive voltage V is fixed, and the pulse width Pw of the drive pulse signal applied to the electrothermal transducer 2002 is changed (gradually shortened).

  As the fixed head driving voltage V, the head driving voltage Vop multiplied by the margin value k stored in the memory unit 6003 of the recording head IH is directly used as the fixed voltage. In this case, since the pulse width is changed with the voltage fixed, the driving energy changes depending on the pulse width.

  When the drive energy threshold detection sequence is started, the head drive voltage V is fixedly set at (Vop) (S18).

  Next, the measurement start value of the pulse width Pw is determined based on the information stored in the memory unit 6003 of the recording head IH. As this measurement start value, a higher value that ensures ejection of ink droplets is employed.

  When the supply start pulse width Pw is determined (S18a), the recording head is driven for a predetermined period by a predetermined driving pattern set in advance using the determined pulse width Pw and the head driving voltage V (S19). ). Normally, all the heating resistance elements are driven, but some selected heating resistance elements may be driven as long as the head temperature change can be reliably detected. Here, a predetermined drive pattern and a certain period are determined according to the nozzle to be used, the drive frequency, the number of drive pulses, and the like.

  Immediately after the end of the head drive for a certain period, the head temperature T detected by the head temperature detection sensor 7001 is acquired (S20). The acquired head temperature T is stored in the drive energy threshold detection unit 7011 in a format associated with the pulse width Pw at this time.

  Next, the pulse Pw is reduced by a predetermined value (the resolution with variable pulse width possessed by the head drive circuit), and the recording head is driven again for a certain period by the same drive pattern as the previous time. T is acquired (S22 to S20). The acquired head temperature T is also stored in the drive energy threshold detection unit 7011 in a format associated with the pulse width Pw at this time. A series of these processes are repeatedly executed to obtain a threshold pulse width Pth for determining the presence or absence of ink ejection (S23).

  The threshold pulse width Pth can be obtained by detecting the inflection point or the minimum temperature value based on the data indicating the correspondence relationship between the stored pulse width Pw and the head temperature T.

  In the case of Example 2, since an appropriate drive voltage Vop is used as it is at the time of measurement, a value obtained by multiplying the calculated pulse width threshold Pth by K2 (because the pulse width has a square root relationship with the voltage) is appropriate. The value Pop is used. In this case, Vop is a suitable driving voltage.

  As described above, the optimum drive energy detection unit 7012 obtains an appropriate drive pulse width Pop (S24), feeds back the memory unit 6003 and the head drive control unit 7008 of the recording head IH, and stores information in the memory unit 6003. Is updated with the new data Pop. At the same time, the drive condition of the head drive controller 7008 is changed (S26).

  However, as described above, when a non-rewritable memory element such as a fuse ROM or the rank resistor is used as the memory unit 6003, the memory unit 6003 is not rewritten, and only the drive condition setting change of the head drive control unit 7008 is performed. I do.

  FIG. 10 is a flowchart showing the operation of the ink jet recording apparatus which is Embodiment 3 of the present invention.

  First, when a discharge failure detection command is received from the main body, it is checked in S11 whether there is a history of heater failure in the past. If there is no history of heater failure in the past, the optical sensor detects an undischarge nozzle in S12. As a result, when a non-ejection nozzle is detected, in S13, the nozzle is disabled and registered by mask processing or the like. Thereafter, in S14, it is determined whether or not all nozzles have been inspected.

  After the inspection is completed for all nozzles, if an undischarge nozzle is detected in S15, a current leak is measured.

  In S16, a voltage is applied to the VH electrode 4001. Then, immediately after the voltage is applied (S16a), if an ink leak has occurred inside the recording head, a leak current flows, and the leak current is measured. In S17, it is determined whether or not the leakage current has been detected. That is, the normal current value is almost zero A (μA order), but if ink leakage occurs, a current of mA order flows. If this leakage current is detected, the process proceeds to a discharge threshold measurement step in S18. . If the leakage current cannot be detected, the discharge failure detection process is terminated.

  In the memory unit 6003 of the recording head IH, as described above, a voltage (K · Vth) obtained by multiplying the ink discharge threshold voltage Vth measured in advance by a predetermined margin value K is stored as an appropriate head driving voltage Vop. ing. Therefore, when driving each electrothermal transducer 2002 of the recording head IH, the head drive control unit 7008 reads a suitable head drive voltage Vop from the memory unit 6003, and based on this voltage value Vop, the actual drive voltage To decide.

  In the third embodiment, driving energy that sequentially decreases is supplied to each electrothermal transducer 2002 of the recording head IH, and the head temperature corresponding to each driving energy is measured. However, at this time, in the third embodiment, the head drive voltage V is fixed, and the pulse width Pw of the drive pulse signal applied to the electrothermal transducer 2002 is changed (gradually shortened).

  As the fixed head driving voltage V, the head driving voltage Vop multiplied by the margin value k stored in the memory unit 6003 of the recording head IH is directly used as the fixed voltage. In this case, since the voltage is fixed and the pulse width is changed, the drive energy changes depending on the pulse width.

  When the drive energy threshold detection sequence is started, the head drive voltage V is fixedly set at (Vop) (S18).

  Next, the measurement start value of the pulse width Pw is determined based on the information stored in the memory unit 6003 of the recording head IH. As this measurement start value, a higher value that ensures ejection of ink droplets is employed.

  When the supply start pulse width Pw is determined (S18a), using the determined pulse width Pw and the head driving voltage V, the recording head is driven for a certain period by a predetermined driving pattern set in advance (S19). ). Normally, all the heating resistance elements are driven. However, if a change in head temperature can be detected reliably, some selected heating resistance elements may be driven. Here, a predetermined drive pattern and a certain period are determined according to the nozzle to be used, the drive frequency, the number of drive pulses, and the like.

  Immediately after the end of the head drive for a certain period, the head temperature T detected by the head temperature detection sensor 7001 is acquired (S20). The acquired head temperature T is stored in the drive energy threshold detection unit 7011 in a format associated with the pulse width Pw at this time.

  Next, the pulse Pw is reduced by a predetermined value (the resolution with variable pulse width that the head drive circuit has), and the recording head is driven again for a certain period in the same drive pattern as the previous time. The temperature T is acquired (S22 to S20). The acquired head temperature T is also stored in the drive energy threshold detection unit 7011 in a format associated with the pulse width Pw at this time.

  These series of processes are repeated and executed to obtain a threshold pulse width Pth for determining the presence or absence of ink ejection (S23).

  A threshold pulse width Pth is obtained by detecting an inflection point, a minimum temperature value, or the like based on data indicating a correspondence relationship between the stored pulse width Pw and the head temperature T.

  In the case of Example 3, since an appropriate drive voltage Vop is used as it is at the time of measurement, a value obtained by multiplying the calculated pulse width threshold Pth by K2 (because the pulse width has a square root relationship with the voltage) is appropriate. The value Pop is used. In this case, Vop is a suitable driving voltage.

  As described above, the optimum drive energy detection unit 7012 obtains an appropriate drive pulse width Pop (S24), feeds back the memory unit 6003 and the head drive control unit 7008 of the recording head IH, and stores information in the memory unit 6003. Is updated with the new data Pop. Further, the drive condition of the head drive controller 7008 is changed (S26).

  However, as described above, when a non-rewritable memory element such as a fuse ROM or the rank resistance is used as the memory unit 6003, only the driving condition of the head drive control unit 7008 is set without rewriting the memory unit 6003. change.

  In the first to third embodiments, in order to prevent the recording apparatus from being contaminated by the ejection of ink droplets, the recording head is placed at a recovery position where a suction recovery system unit 1006 is arranged or a preliminary ejection preliminary ejection position (not shown). It is preferable to arrange 1H.

  In addition, since the head temperature T corresponding to the pulse width Pw is repeatedly acquired, if the recovery process is added every time after the head temperature is acquired, the head temperature T quickly returns to the initial state as compared with the case where it is left unattended. Tact up.

  In the third embodiment, the driving voltage is fixed, the pulse width of the driving pulse signal is changed, and the driving energy supplied to the recording head is changed. Instead, the pulse width is fixed and the driving energy is changed. The voltage may be changed.

  In the third embodiment, the driving pulse width is gradually reduced, but conversely, the driving pulse width may be gradually increased.

Other examples

  Although the embodiments have been described above, the form of the recording apparatus is not limited to the recording apparatus that performs recording by scanning the recording head, and is a full-line type recording having a length corresponding to the maximum width of the recording medium. You may apply to the recording device which records using a head.

1 is a schematic view showing an ink jet recording apparatus 1000 that is Embodiment 1 of the present invention. FIG. It is a figure which shows the structural example of the inkjet recording head IH. FIG. 10 is a schematic diagram illustrating a nozzle detection configuration 3000 in which ink is not ejected from the inkjet recording head IH. It is a figure which shows the structure of the contact pad electrode part 4000 of an inkjet recording head. It is a figure which shows the time change of leak current. It is a block diagram which shows the control system used for the inkjet recording device carrying an inkjet recording head. It is a block diagram which shows the control system used for the inkjet recording device carrying an inkjet recording head. 3 is a flowchart illustrating an operation procedure in the first embodiment. It is a flowchart which shows operation | movement of the inkjet recording device which is Example 2 of this invention. 6 is a flowchart showing an operation in an inkjet recording apparatus that is Embodiment 3 of the present invention. It is a figure which shows the correspondence of the head temperature T stored in the drive energy threshold value detection part 7011, and pulse width Pw (drive energy E).

Explanation of symbols

1000: Inkjet recording apparatus,
IH ... recording head,
IT ... ink tank,
HC ... Head cartridge,
CR ... carriage,
1005 ... Recording sheet,
1006 ... suction recovery system unit,
2001 ... Ink ejection port,
2002 ... electrothermal transducer,
2003 ... Ink supply port,
2004 ... ink flow path,
2005 ... substrate,
3004 ... Ink drops,
4000 ... contact pad electrode part,
4001 ... VH electrode,
4002 ... GNDH electrode,
4003 ... VHT electrode,
4004 ... VDD electrode,
4005 ... GNDL electrode,
4006 ... A plurality of signal lines and non-contact pads,
6002 ... control unit,
6003 ... Memory part,
6004 ... Mechanical control unit,
6008 ... Display element control unit,
6009 ... display element part,
6010: Recording head control unit,
7001... Head temperature detection sensor,
7003 ... Undischarge nozzle detection unit,
7004 ... Heater failure detection sequence determination unit,
7005 ... Head temperature detection circuit,
7006 ... Environmental temperature detection sensor,
7007 ... Environmental temperature detection circuit,
7008 ... Head drive control unit,
7009 ... Print control unit,
7010 ... Drive energy threshold value detection sequence determination unit,
7011 ... Drive energy threshold value detection unit,
7012 ... Optimal drive energy detector,
7013 ... Undischarge nozzle detection sequence determination unit,
7014: Heater failure detection unit.

Claims (9)

In an inkjet recording apparatus for recording by discharging ink droplets from an inkjet recording head to a recording medium by driving a heating resistor element,
Non-ejection nozzle detection means for detecting non-ejection nozzles among the ejection nozzles constituting the inkjet recording head;
Drive condition detection means for detecting a drive condition of the inkjet recording head when a non-ejection nozzle is detected among the ejection nozzles constituting the inkjet recording head;
When it is detected that the driving conditions stored in the inkjet recording head are different, the driving conditions stored in the inkjet recording head are rewritten, and the driving energy supplied when the inkjet recording head is driven is changed. Change means;
An ink jet recording apparatus comprising: In claim 1,
The driving condition of the ink jet recording head is a condition obtained by supplying a plurality of different driving energies to the ink jet recording head and monitoring the temperature of the ink jet recording head corresponding to each of the driving energy. An inkjet recording apparatus. In an inkjet recording apparatus for recording by discharging ink droplets from an inkjet recording head to a recording medium by driving a heating resistor element,
Current leakage detection means for detecting current leakage in the order of mA via ink provided in the ink jet recording head;
Driving condition detecting means for detecting the driving condition of the ink jet recording head when the current leak is detected;
Means for rewriting the driving conditions stored in the ink jet recording head when the current leak is detected, and changing the driving energy supplied when the ink jet recording head is driven;
An ink jet recording apparatus comprising: In claim 3,
Measure the current flowing by applying a potential between an electrode pad having the same potential as the silicon substrate on which the heating resistor element is formed and an electrode pad to which energy for driving the heating resistor element is applied. To obtain an electric current leak through the ink provided in the ink jet recording head. In claim 3 or claim 4,
The driving condition of the ink jet recording head is a condition obtained by supplying a plurality of different driving energies to the ink jet recording head and monitoring the temperature of the ink jet recording head corresponding to each of the driving energy. An inkjet recording apparatus. In an inkjet recording apparatus for recording by discharging ink droplets from an inkjet recording head to a recording medium by driving a heating resistor element,
Non-ejection nozzle detection means for detecting non-ejection nozzles among the ejection nozzles constituting the inkjet recording head;
Current leakage detection means for detecting current leakage in the order of mA via ink provided in the ink jet recording head;
In the case where a non-ejection nozzle is detected among the ejection nozzles constituting the inkjet recording head and a current leak in the order of mA is detected through the ink provided in the inkjet recording head, the inkjet recording head Change means for detecting the drive condition and changing the drive energy supplied when the inkjet recording head is driven;
An ink jet recording apparatus comprising: In claim 6,
By applying a potential between an electrode pad having the same potential as the silicon substrate on which the heating resistor element is formed and an electrode pad for applying energy for driving the heating resistor element, and measuring the flowing current An ink jet recording apparatus for obtaining a current leak through ink provided in the ink jet recording head. In claim 6 or claim 7,
The driving condition of the ink jet recording head is a condition obtained by supplying a plurality of different driving energies to the ink jet recording head and monitoring the temperature of the ink jet recording head corresponding to each of the driving energy. Inkjet recording apparatus. In a control method of an ink jet recording apparatus that records by discharging ink droplets from an ink jet recording head to a recording medium by driving a heating resistor element,
A non-ejection nozzle detecting step of detecting a non-ejection nozzle among the ejection nozzles constituting the inkjet recording head;
A drive condition detection step of detecting a drive condition of the inkjet recording head when a non-ejection nozzle is detected among the ejection nozzles constituting the inkjet recording head;
When it is detected that the driving conditions stored in the inkjet recording head are different, the driving conditions stored in the inkjet recording head are rewritten, and the driving energy supplied when the inkjet recording head is driven is changed. Change process;
A method for controlling an ink jet recording apparatus, comprising:

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