JP2013082080A - Image recording apparatus - Google Patents

Abstract

When a recording element such as a nozzle for ejecting ink has deteriorated, the use of the recording element is stopped before the recording element fails.
A resistance value of a heater resistance provided for each of a plurality of nozzles that eject ink is measured, and it is determined whether the heater resistance is deteriorated from a predetermined state based on the resistance value. Is deteriorated from a predetermined state, the application of voltage to the heater resistance is prohibited.
[Selection] Figure 2

Description

  The present invention relates to an image recording apparatus that records an image on a recording material, for example, an image recording apparatus such as a color printer.

  2. Description of the Related Art Conventionally, an ink jet type image recording apparatus that performs image recording on recording paper by ejecting ink from nozzles as recording elements of a recording head is known.

  OA equipment such as personal computers, copiers, word processors, etc. are becoming more and more colored with higher functionality, and various color ink jet recording devices are provided as one of the image forming (recording) devices in these devices. Has been.

  A typical ink jet recording apparatus includes a carriage having a recording head and an ink tank, a transport mechanism for transporting recording paper, and control means for controlling these operations. A carriage equipped with a recording head that discharges ink droplets from a plurality of ejection openings is serially scanned in a direction (hereinafter also referred to as a main scanning direction) orthogonal to a recording paper transport direction (hereinafter also referred to as a sub-scanning direction). During this time, ink is ejected onto the recording paper. On the other hand, the recording paper is intermittently conveyed by an amount related to the recording width between the scans, and a plurality of scans and paper conveyance are performed to record all image areas.

  When performing color recording, a plurality of recording heads are provided according to the colors of a plurality of types of ink, and a color image is formed by overlapping ink droplets ejected from these recording heads or landing in close proximity. Record.

  As described above, there is an increasing demand for inkjet recording apparatuses in a wide range of industrial fields as relatively simple and excellent recording means, and there is a demand for higher printing speeds and provision of higher-quality images. It has been.

  In general, the recording head has a structure in which a heater resistance and a transistor switch for receiving an external electric control signal are connected in series, and a predetermined recording head driving voltage is applied to the heater resistance as a bias voltage. As applied. In this state, an electric control signal for determining whether or not ink is ejected from the recording head is given from the outside, and the transistor switch is turned on to energize. When the transistor switch is turned on and energized, a current flows through the heater resistance, and the ink in the vicinity of the heater resistance is boiled to form an image by ejecting ink from the ink ejection holes (nozzles) toward the recording paper. It has become.

  Although there is a manufacturing variation in the resistance value of the heater resistance described above, a technique for stabilizing ink ejection characteristics is disclosed in Patent Document 1, for example. In the technique disclosed in Patent Document 1, the heater resistance value of each nozzle in the recording head is measured at the time of shipping inspection, and information is stored in the memory in the head. Then, based on the stored information, the main body changes the control for each nozzle, and performs the optimum control for the measured heater resistance value.

  Here, a circuit failure such as disconnection of the head or a short circuit may occur for some reason, resulting in an ejection failure. If there is a nozzle that does not eject ink, when the recording head is driven in the main scanning direction with respect to the recording medium, streaky noise occurs in the recording medium at the position of the nozzle that does not eject ink along the main scanning direction. As a result, the recording quality is significantly reduced.

  Patent Document 2 discloses a method for detecting ejection failure of a nozzle as means for preventing the deterioration of recording quality. In addition to this, Patent Document 3 discloses a method of performing recording using an adjacent recording element instead of a recording element that has caused ejection failure. Further, Patent Document 4 discloses a method of performing printing with a multi-pass printing and printing at a location where a nozzle having a defective ejection should be printed by different printing elements of different scans, as described above. Means have been proposed that compensate for nozzle ejection defects and suppress the degradation of print quality.

  As another means, head driving (short pulse driving) capable of predicting current consumption is performed by the head driving means, the head current consumption at that time is detected by the head current detecting means, and the predicted current value is detected by the control / predicting means. A method for judging a head failure by comparing current values is disclosed in Patent Document 5.

JP 2006-168021 A JP-A-11-188853 JP 2001-315318 A JP 2000-2111167 A JP 2006-218744 A

  There is a known problem that the presence of a malfunctioning nozzle as described above damages the surrounding non-malfunctioning nozzles and shortens the service life. To solve this problem, use the nozzle before it malfunctions. Need to stop.

  However, the techniques described in Patent Documents 2 to 5 have a problem in that the use of the nozzles cannot be stopped before the failure, resulting in a failed nozzle and an increase in the life of the recording head itself. .

  The present invention has been made in view of the problems of the conventional techniques as described above, and when a recording element such as a nozzle for ejecting ink has deteriorated, before the recording element breaks down. An object of the present invention is to provide an image processing apparatus capable of stopping use of a recording element.

In order to achieve the above object, the present invention provides:
A heating resistor is provided for each of the plurality of recording elements that eject ink, and the plurality of recording elements are heated by selectively applying a voltage to the heating resistor under the control of an image generating unit. An image recording apparatus that performs recording by selectively discharging ink to a recording material from
Measuring means for measuring the resistance value of the heating resistor;
Based on the resistance value of the heating resistor measured by the measuring means, it is determined whether or not the heating resistor is deteriorated from a predetermined state, and the heating resistor is deteriorated from the predetermined state. And determining means for prohibiting the image generating means from applying a voltage to the heating resistor.

  As described above, in the present invention, the resistance value of the heating resistor provided for each of the plurality of recording elements that eject ink is measured, and the heating resistor is deteriorated from a predetermined state based on the resistance value. When the heating resistor is deteriorated from a predetermined state, the recording element such as a nozzle for discharging ink is deteriorated because the voltage application to the heating resistor is prohibited. The recording element can be stopped before the recording element fails.

1 is a perspective view showing a schematic configuration mainly of a recording unit of an ink jet recording apparatus which is an embodiment of an image recording apparatus of the present invention. 1 is a block diagram showing a basic configuration of Embodiment 1 of an image recording apparatus of the present invention. FIG. 3 is a circuit diagram showing an internal structure of the recording head shown in FIG. 2. 3 is a flowchart for explaining a procedure for determining the life of a nozzle in the ink jet recording apparatus shown in FIG. 2. It is a block diagram which shows the basic composition of Example 2 of the image recording device of this invention. 6 is a flowchart for explaining a procedure for determining the life of a nozzle in the ink jet recording apparatus shown in FIG. 5.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view mainly showing a schematic configuration of a recording unit of an ink jet recording apparatus as an embodiment of the image recording apparatus of the present invention.

  As shown in FIG. 1, the ink jet recording apparatus according to this embodiment performs recording on recording paper 209 as a recording material by detachably mounting an ink cartridge 201 and a head cartridge 202 containing recording element arrays on a carriage 203. Is.

  The ink cartridge 201 individually stores inks of four colors of black (Bk), cyan (C), magenta (M), and yellow (Y), and configures the respective storage chambers integrally. . The head cartridge 202 is used in the form of one unit in which a total of eight recording element arrays corresponding to each ink stored in the ink cartridge 201 are stored for each color. That is, the head cartridge 202 has two recording element arrays for ejecting the respective Bk, C, M, and Y inks for each color, for a total of eight recording elements. The carriage 203 can move in the x direction in the drawing along the guide shaft 210 by being slidably engaged with the guide shaft 210.

  An encoder scale 204 is provided on the surface facing the carriage 203, and slits are provided at intervals of 150 lpi. The encoder scale 204 is irradiated with light emitted from an encoder sensor (not shown), and A-phase and B-phase signals based on the transmitted light are output according to the scanning position of the carriage 203. The B phase signal has a phase relationship that is 90 degrees behind the A phase signal.

  The recording paper 209 is fed to an area facing the carriage 203 while being sandwiched between a pair of paper feed rollers 207 and 208. The recording paper 209 is sandwiched between the paper feed roller 205 and the auxiliary roller 206 and is conveyed in the y direction in the figure.

Example 1
FIG. 2 is a block diagram showing the basic configuration of the image recording apparatus according to the first embodiment of the present invention.

  As shown in FIG. 2, the image recording apparatus according to the present embodiment includes an image generation IC 101 serving as an image generation unit, a recording head 104, an on-carriage IC 109, a voltage source selection circuit 107, a first voltage source 105, and a first voltage source 105. 2 voltage sources 106.

  The image generation IC 101 is provided in the main body of the inkjet recording apparatus, receives image data sent from a host, and processes the received image data into drive data for ejecting ink from the recording head 104. Then, the processed drive data is transmitted to the recording head 104 together with a driving timing signal for giving the timing at which the recording head 104 ejects ink. Inside the image generation IC 101, a recording data generation circuit 102 and a recording timing generation circuit 103 are provided. The print data generation circuit 102 processes the image data into drive data for ejecting ink from the print head 104 and transmits the drive data to the print head 104. The recording timing generation circuit 103 generates a drive timing signal that gives the timing at which the recording head 104 ejects ink, and transmits it to the recording head 104. The drive timing signal generated by the recording timing generation circuit 103 is also transmitted to the A / D conversion circuit 110 in the on-carriage IC 109. This will be described later when the A / D conversion circuit 110 is described.

  The recording head 104 selectively ejects ink from a plurality of nozzles serving as recording elements based on the drive data and drive timing transmitted from the image generation IC 101 to form an image on the recording paper 209. Each of the plurality of nozzles is provided with a heater resistor serving as a heating resistor, and a voltage is selectively applied to the heater resistor under the control of the image generation IC 101 to heat the heater resistor and eject ink. To do. Further, the recording head 104 includes a nonvolatile storage device (not shown) such as a ROM therein, and stores the heater resistance values of the plurality of nozzles in the recording head 104 measured at the time of shipping inspection. .

  FIG. 3 is a circuit diagram showing the internal structure of the recording head 104 shown in FIG.

  As shown in FIG. 3, the recording head 104 shown in FIG. 2 is provided with a heater resistor 301 for each of a plurality of nozzles. Further, each of the heater resistors 301 is connected to a current switch control transistor (MOSFET) 302 for performing switch control of energization / non-energization of the current flowing through the heater resistor 301. Further, an AND gate 303 is connected to the gate terminal of the current switch control transistor 302, and a drive data signal and a drive timing signal transmitted from the image generation IC 101 are input. Then, an input signal corresponding to a desired nozzle that ejects ink is asserted based on a drive data signal transmitted from the image generation IC 101, and a drive timing signal is asserted at a desired timing when ink is ejected. The output of the gate 303 is asserted, and a voltage is selectively applied to the gate terminal of the current switch control transistor 302.

  The voltage source 105 is a voltage source of 21.5 V and serves as a voltage source when performing a normal printing operation. The voltage source 106 is a voltage source of 5 V, and serves as a voltage source when performing a life determination indicating a deterioration state of a heater resistance provided in a nozzle in the recording head 104.

  The voltage source selection circuit 107 selects a voltage source to be supplied to the recording head 104 from either the voltage source 105 or the voltage source 106 by switching an internal circuit. When recording on the recording paper 209, the voltage from the voltage source 105 is applied to the heater resistor 301, and when measuring the resistance value of the heater resistor 301, the voltage from the voltage source 106 is applied to the heater resistor 301. The voltage source supplied to the recording head 104 is switched by an internal circuit. The voltage source selection circuit 107 may be switched by the image generation IC 101 or an on-carriage IC 109 described later.

  A resistor 108 is connected between the voltage source 105, the voltage source selection circuit 107, and the A / D conversion circuit 110. When a voltage from the voltage source 106 is applied to the recording head 104 by the voltage source selection circuit 107 and a current is passed through only one heater resistor 301 by a drive data signal and a drive timing signal transmitted from the image generation IC 101. A voltage value obtained by dividing 5 V by the resistor 108 and the heater resistor 301 is applied to the A / D conversion circuit 110. As a result, the resistance value of the heater resistor 301 is measured, and the voltage source 106, the resistor 108, and the voltage source selection circuit 107 constitute the measuring means in the present invention.

  The on-carriage IC 109 reads the measured resistance value of the heater resistor 301 and determines the life of the corresponding nozzle. In the on-carriage IC 109, an A / D conversion circuit 110, a heater resistance life determination circuit 111 serving as a determination unit, and an LUT 112 are provided. The A / D conversion circuit 110 converts an input analog voltage value into a digital value by using a drive timing signal generated by the recording timing generation circuit 103 for ejecting ink by the recording head 104 as a trigger. The transmitted data is transmitted to the heater resistance life determination circuit 111. By performing A / D conversion at this timing, it is possible to take in an analog voltage value obtained by dividing 5 V by the resistor 108 and the heater resistor 301 to be measured. The LUT 112 holds a table in which values output from the A / D conversion circuit 110 are associated with heater resistance values. When the heater resistance life determination circuit 111 receives data from the A / D conversion circuit 110, the heater resistance life determination circuit 111 refers to the LUT 112 and derives the resistance value of the heater resistance provided in the target nozzle. Then, the derived resistance value is compared with the resistance value of the heater resistance provided in the nozzle measured at the time of shipping inspection, and the derived resistance value is a predetermined range from the resistance value measured at the time of shipping inspection. It is determined whether or not the heater resistance is deteriorated from a predetermined state by confirming whether or not the fluctuation is 10% or more. When the derived resistance value fluctuates 10% or more than the resistance value measured at the time of the shipping inspection, it is determined that the heater resistance is deteriorated from a predetermined state, and the recording data generation circuit 102 is determined. Transmission of drive data for the nozzle provided with the heater resistance is stopped. As a result, the heater resistance is deteriorated from a predetermined state and the subsequent use of the nozzle determined to have a life is prohibited.

  Here, the reason why the voltage source supplied to the recording head 104 is set to 5 V when determining the life of the nozzle will be described.

  When performing normal printing, a voltage of 21.5 V is applied for about 1 microsecond, and the heater resistor 301 is heated suddenly to cause the ink in the vicinity of the heater resistor 301 to boil and eject the ink. However, if a voltage is continuously applied to the heater resistor 301 for a long time, the heater resistor 301 may be damaged, or in the worst case, the heater resistor 301 may be disconnected.

  On the other hand, in order to measure the resistance value of the heater resistor 301, a time of about several tens of microseconds is required in consideration of the time until the voltage input to the A / D conversion circuit 110 is stabilized after the voltage is applied. It is said.

  For this reason, when measuring the life of the nozzle, the voltage source is set to 5 V so that the heater resistor 301 is not damaged even if it is energized for several tens of microseconds. In the present embodiment, the voltage source for measuring the lifetime is 5 V, but any other voltage value may be used as long as it does not damage the heater resistor 301.

  The procedure for determining the life of the nozzle in the ink jet recording apparatus configured as described above will be described below.

  FIG. 4 is a flowchart for explaining the procedure for determining the life of the nozzles in the ink jet recording apparatus shown in FIG.

  When measurement for determining the life of the nozzle is started (step 501), first, the voltage source selection circuit 107 is switched, and the voltage source supplied to the recording head 104 is set to the voltage source 106 of 5V (step 502).

  Next, drive data for energizing only the nozzle provided with the heater resistor 301 for measuring the resistance value is transmitted from the image generation IC 101 to the recording head 104 (step 503). As a result, a voltage value obtained by dividing 5 V by the resistor 108 and the heater resistor 301 is applied to the A / D conversion circuit 110.

  The A / D conversion circuit 110 converts the applied analog voltage value into a digital value using the drive timing signal generated by the recording timing generation circuit 103 as a trigger, and the converted data is converted into a heater resistance life determination circuit 111. (Step 504).

  In the heater resistance life determination circuit 111, the resistance value of the heater resistance 301 provided in the nozzle of interest is derived with reference to the LUT 112 (step 505).

  Then, in the heater resistance life determination circuit 111, it is determined whether or not the resistance value derived in step 505 varies by 10% or more than the resistance value measured at the time of the shipping inspection (step 506).

  If the resistance value derived in step 505 has fluctuated by 10% or more, it is determined that the heater resistance 301 is deteriorated from a predetermined state, and the heater resistance 301 is provided for the recording data generation circuit 102. The transmission of drive data for the selected nozzle is stopped. Thereby, the heater resistance is deteriorated from a predetermined state and the use of the nozzle determined to have a lifetime is prohibited (step 507).

  Then, it is determined whether or not the measurement of the resistance value of the heater resistor 301 has been completed for all the nozzles (step 508). If the measurement has been completed, the voltage source selection circuit 107 is switched and supplied to the recording head 104. The voltage source is a 21.5 V voltage source 105 (step 509).

  Then, the measurement is finished.

  If the resistance value has not fluctuated by 10% or more, the process proceeds to step 508 without performing the process in step 507, and the measurement of the resistance value of the heater resistor 301 has not been completed for all nozzles. In this case, the process returns to step 503 to measure the resistance value of the heater resistance provided in the nozzle that has not been measured yet.

  As described above, in this embodiment, it is possible to determine the life of the nozzle at a predetermined timing during the operation of the actual machine, and it is possible to stop the use of the nozzle before failure.

  In this embodiment, when the resistance value of the heater resistor 301 fluctuates by 10% or more than the resistance value measured at the time of shipping inspection, the use of the nozzle is prohibited. The ratio is arbitrary, and it may be 5% or 20% as long as it is before the nozzle breaks down. Further, the timing for performing the measurement is not particularly limited because there is no element that defines the timing, and may be arbitrary, and may be every predetermined number of printed sheets or every predetermined time.

(Example 2)
FIG. 5 is a block diagram showing the basic configuration of Embodiment 2 of the image recording apparatus of the present invention.

  As shown in FIG. 4, the image recording apparatus according to the present embodiment includes an image generation IC 401 serving as an image generation unit, a recording head 404, an on-carriage IC 409, a voltage source selection circuit 407, a first voltage source 405, and a first voltage source 405. 2 voltage sources 406.

  An image generation IC 401 is provided in the main body of the ink jet recording apparatus, receives image data sent from a host, and processes the received image data into drive data for ejecting ink from the recording head 404. Then, the processed driving data is transmitted to the recording head 404 together with a driving timing signal for giving the timing at which the recording head 404 ejects ink. Inside the image generation IC 401, a recording data generation circuit 402 and a recording timing generation circuit 403 are provided. The print data generation circuit 402 processes the image data into drive data for ejecting ink from the print head 404 and transmits the drive data to the print head 404. The recording timing generation circuit 403 generates a drive timing signal that gives the timing at which the recording head 404 ejects ink, and transmits the drive timing signal to the recording head 404. The drive timing signal generated by the recording timing generation circuit 403 is also transmitted to the A / D conversion circuit 410 in the on-carriage IC 409. This will be described later when the A / D conversion circuit 410 is described.

  The recording head 404 selectively ejects ink from a plurality of nozzles serving as recording elements based on the drive data and drive timing transmitted from the image generation IC 401 to form an image on the recording paper 209. Each of the plurality of nozzles is provided with a heater resistor serving as a heating resistor, and a voltage is selectively applied to the heater resistor under the control of the image generation IC 401 to heat the heater resistor and eject ink. To do. The recording head 404 includes a nonvolatile storage device (not shown) such as a ROM therein, and stores the heater resistance values of the plurality of nozzles in the recording head 404 measured at the time of shipping inspection. . The internal structure of the recording head 404 is the same as that shown in FIG.

  The voltage source 405 is a voltage source of 21.5 V and serves as a voltage source when performing a normal printing operation. The voltage source 406 is a voltage source of 5 V, and serves as a voltage source for performing life determination indicating a deterioration state of a heater resistance provided in a nozzle in the recording head 404.

  The voltage source selection circuit 407 selects a voltage source to be supplied to the recording head 404 from either the voltage source 405 or the voltage source 406 by switching an internal circuit. When recording on the recording paper 209, the voltage from the voltage source 405 is applied to the heater resistance, and when measuring the resistance value of the heater resistance, the recording head is configured so that the voltage from the voltage source 406 is applied to the heater resistance. The voltage source supplied to 404 is switched by an internal circuit. The voltage source selection circuit 107 may be switched by the image generation IC 401 or an on-carriage IC 409 described later.

  A resistor 408 is connected between the voltage source 405, the voltage source selection circuit 407 and the A / D conversion circuit 410. When a voltage from the voltage source 406 is applied to the recording head 404 by the voltage source selection circuit 407 and a current is passed through only one heater resistor by a drive data signal and a drive timing signal transmitted from the image generation IC 401, A voltage value obtained by dividing 5 V by the resistor 408 and the heater resistor is applied to the A / D conversion circuit 410. As a result, the resistance value of the heater resistance is measured, and the voltage source 406, the resistor 408, and the voltage source selection circuit 407 constitute the measuring means in the present invention.

  The on-carriage IC 409 reads the measured resistance value of the heater resistance and determines the life of the corresponding nozzle. Inside the on-carriage IC 409, an A / D conversion circuit 410, a heater resistance life determination circuit 411 as a determination unit, an LUT 412, a RAM 413 as a storage unit, and a bus 414 are provided. The A / D conversion circuit 110 converts the input analog voltage value into a digital value by using the drive timing signal generated by the recording timing generation circuit 103 for ejecting ink by the recording head 404 as a trigger. The stored data is stored in the RAM 413. By performing A / D conversion at this timing, an analog voltage value obtained by dividing 5 V by the resistance 408 and the heater resistance to be measured can be captured. The LUT 412 holds a table in which values output from the A / D conversion circuit 410 are associated with heater resistance values. The heater resistance life determination circuit 411 reads the resistance value of the heater resistance measured up to the previous three times in a predetermined cycle from the RAM 413 for the nozzle of interest, and refers to the LUT 412 to derive the resistance value of the heater resistance for each. Then, by confirming whether or not the difference between the minimum value and the maximum value of the derived resistance value is 10% or more of the past resistance value among the three times, the variation amount of the resistance value of the heater resistance is It is determined whether it is larger than a predetermined value. It is determined whether or not the heater resistance is deteriorated from a predetermined state. If the difference between the minimum value and the maximum value of the derived resistance value is 10% or more of the past resistance value among the three times, and the variation of the resistance value of the heater resistance is larger than a predetermined value, the heater resistance Is determined to be deteriorated from a predetermined state, and transmission of drive data for the nozzle provided with the heater resistance to the print data generation circuit 402 is stopped. As a result, the heater resistance is deteriorated from a predetermined state and the subsequent use of the nozzle determined to have a life is prohibited.

  The RAM 413 stores the data output from the A / D conversion circuit 410. Thereby, the RAM 413 stores a plurality of resistance values measured at a predetermined cycle for each heater resistance. The capacity of the RAM 413 is determined by the total number of nozzles, the bit length output by the A / D conversion circuit 410, and the number of past measurement data to be stored.

  The bus 414 connects the A / D conversion circuit 410, the heater resistance life determination circuit 411, and the RAM 413.

  The procedure for determining the life of the nozzle in the ink jet recording apparatus configured as described above will be described below.

  FIG. 6 is a flowchart for explaining the procedure for determining the life of the nozzles in the ink jet recording apparatus shown in FIG.

  When measurement for determining the life of the nozzle is started (step 601), first, the voltage source selection circuit 407 is switched, and the voltage source supplied to the recording head 404 is set to a voltage source 406 of 5V (step 602).

  Next, drive data for energizing only the nozzle provided with the heater resistance for measuring the resistance value is transmitted from the image generation IC 401 to the recording head 404 (step 603). As a result, a voltage value obtained by dividing 5 V by the resistor 408 and the heater resistor is applied to the A / D conversion circuit 410.

  Next, the A / D conversion circuit 410 converts the applied analog voltage value into a digital value using the drive timing signal generated by the recording timing generation circuit 403 as a trigger (step 604).

  Then, the data converted into the digital value is stored in the RAM 413 (step 605).

  Thereafter, the heater resistance life determination circuit 411 determines whether or not the past three measurement data exist in the RAM 413 (step 606), and returns to step 603 if the past three measurement data does not exist.

  On the other hand, if there are measurement data for the past three times in the RAM 413, the heater resistance life determination circuit 411 reads the data for the past three times from the RAM 413 (step 607).

  Next, the heater resistance life determination circuit 411 refers to the LUT 412 and derives the resistance value of the heater resistance provided in the nozzle for each of the three data read from the RAM 413 (step 608).

  Then, in the heater resistance life determination circuit 411, it is determined whether or not the difference between the minimum value and the maximum value of the resistance value derived in step 608 is 10% or more of the past resistance value among the three times. . If the difference between the minimum and maximum resistance values derived in step 608 is 10% or more of the past resistance value among the three times, the heater resistance has deteriorated from a predetermined state. Then, it is determined that the life of the nozzle is reached (step 609), and transmission of drive data for the nozzle provided with the heater resistance is stopped with respect to the print data generation circuit 402 (step 610).

  Then, it is determined whether or not the measurement of the resistance value of the heater resistance has been completed for all the nozzles (step 611). If the measurement has been completed, the voltage supplied to the recording head 404 is switched by switching the voltage source selection circuit 407. The source is a 21.5 V voltage source 405 (step 612).

  Then, the measurement is finished.

  If the difference between the minimum and maximum resistance values derived in step 608 is not 10% or more of the past resistance value among the three times, the process in step 611 is not performed. If the measurement of the resistance value of the heater resistance is not completed for all the nozzles, the process returns to step 603 to measure the resistance value of the heater resistance provided in the nozzle that has not been measured yet. .

  As described above, in this embodiment, it is possible to determine the life of the nozzle at a predetermined timing during the operation of the actual machine, and it is possible to stop the use of the nozzle before failure.

  In this embodiment, when the difference between the minimum and maximum resistance values measured in the past three times is 10% or more of the past resistance value, the use of the nozzle is prohibited thereafter. I have to. However, how many times the resistance value is referred to in the past is arbitrary, and the resistance value to be compared with the difference between the minimum and maximum resistance values measured in the past is In addition, it is arbitrary what percentage of the resistance value to be referred to is the difference between the minimum value and the maximum value measured in the past. The timing for performing the measurement is not particularly limited because there is no element that defines the timing, and may be arbitrary, and may be every predetermined number of printed sheets or every elapse of a predetermined time.

  In addition, in an ink jet recording apparatus, generally, a defect detecting unit that detects an ink ejection defect in a nozzle is provided. Therefore, in the first and second embodiments described above, for the nozzles provided with the heater resistance determined to be deteriorated from the predetermined state by the heater resistance life determination circuits 111 and 411, the ink resistance is determined after the determination. By adopting a configuration that does not detect ejection failure, it is possible to reduce the time required for the entire ejection failure detection operation.

101, 401 Image generation IC
102, 402 Recording data generation circuit 103, 403 Recording timing generation circuit 104, 404 Recording head 105, 106, 405, 406 Voltage source 107, 407 Voltage source selection circuit 108, 408 Resistance 109, 409 On-carriage IC
110,410 A / D conversion circuit 111,411 Heater resistance life judgment circuit 112,412 LUT
201 Ink cartridge 202 Head cartridge 203 Carriage 204 Encoder scale 205 Paper feed roller 206 Auxiliary roller 207, 208 Paper feed roller 209 Recording paper 210 Guide shaft 301 Heater resistance 302 Current switch control transistor 303 AND gate 413 RAM
414 bus

Claims (5)

A heating resistor is provided for each of the plurality of recording elements that eject ink, and the plurality of recording elements are heated by selectively applying a voltage to the heating resistor under the control of an image generating unit. An image recording apparatus that performs recording by selectively discharging ink to a recording material from
Measuring means for measuring the resistance value of the heating resistor;
Based on the resistance value of the heating resistor measured by the measuring means, it is determined whether or not the heating resistor is deteriorated from a predetermined state, and the heating resistor is deteriorated from the predetermined state. An image recording apparatus comprising: a determination unit that prohibits the image generation unit from applying a voltage to the heating resistor. The image recording apparatus according to claim 1,
A voltage source for selectively applying a voltage to the heating resistor under the control of the image generating means;
The voltage source includes a first voltage source, and a second voltage source that applies a voltage lower than the first voltage source to the heating resistor.
When recording on a recording material, the voltage from the first voltage source is applied to the heating resistor, and when measuring the resistance value of the heating resistor, the voltage from the second voltage source is applied. An image recording apparatus comprising voltage source selection means for switching a voltage selectively applied to the heating resistor under the control of the image generating means so as to be applied to the heating resistor. The image recording apparatus according to claim 1,
The determination unit is an image recording apparatus that determines that the heating resistor is deteriorated from the predetermined state when the resistance value of the heating resistor is out of a predetermined range. The image recording apparatus according to claim 1,
Storage means for storing a plurality of resistance values measured at a predetermined cycle by the measurement means for each one of the heating resistors;
The determination unit is an image recording apparatus that determines that the heating resistor is deteriorated from the predetermined state when a variation amount of the plurality of resistance values stored in the storage unit is larger than a predetermined value. The image recording apparatus according to claim 1,
A defect detection means for detecting an ink ejection defect in the recording element;
The defect detection means does not detect an ink ejection defect after the determination for a recording element provided with a heating resistor that is determined to be deteriorated from the predetermined state by the determination means. Image recording device.

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